Method for identifying initial position of rotor of permanent magnet synchronous motor of non-position sensor

A method for identifying an initial position of a rotor of a permanent magnet synchronous motor of a non-position sensor belongs to the motor control field, and aims at solving the problems of the traditional method for identifying the initial position of magnetic poles of the rotor such as position change of the rotor, low identification precision or complex algorithm. The method comprises the following steps: maintaining the rotor under a static state during the identification process of the initial position of the rotor, injecting a high-frequency voltage signal to a stator winding, carrying out rotational coordinate conversion on three-phase stator current, and acquiring position information of the magnetic poles of the rotor by current components at q axis to obtain an initial judgment value of the magnetic pole position of the rotor; and then injecting two impulse voltage vectors in opposite directions to the stator winding, judging the polarity of the magnetic poles by comparing ...

Voltage orienting frequency conversion controller for open loop non-speed sensor

The invention relates to a voltage orientation frequency-vary controller of an opening-ring no-speed sensor, and a controlling technology of a sensing motor, which overcomes the problems of the poor loaded capacity and the light loaded oscillation of a motor caused by the influences of the factors of the voltage decrease of a stator resistor, rotating difference frequencies, dead areas, and the like in the low-speed running of the traditional constant-voltage frequency-ratio control. The voltage orientation frequency-vary controller is composed of the following units, i.e. a current sensor, avector coordinate changing unit, a PI adjustor, a calculating unit of voltage boosting amount, a sliding-frequency calculating unit, a frequency adder, a first operation unit, a second operation unit, a third operation unit, a fourth operation unit, a fifth operation unit, a sixth operation unit and a SVPWM unit. The PI adjustor is used for controlling the no-power current, and the problem of thelight-loaded ...

Novel fundamental wave positive sequence active current detection method

The invention discloses a novel fundamental wave positive sequence active current detection method, and relates to the field of electric energy quality control. The novel fundamental wave positive sequence active current detection method solves the problems that the detection error is large due to the fact that an existing detection method is applied in an asymmetric system, meanwhile, the dynamic detection speed is low due to the fact that a low-pass filter is adopted in the existing detection method for detection, and calculation is complex due to the fact that alpha beta and dq coordinates are adopted in the existing detection method for conversion. The method comprises the steps of conducting fan-in vector conversion on a three-phase asymmetrical current and a three-phase asymmetric voltage in a power grid, obtaining a fan-in current and a fan-in voltage, extracting a fundamental wave positive sequence current and a fundamental wave positive sequence voltage from the fan-in current ...

Train fault overhaul terminal system based on mobile terminal

The invention relates to a train fault overhaul terminal system based on a mobile terminal. The train fault overhaul terminal system comprises an identity authentication module, a system initialization module, a fault picture processing module, a form editing and submitting module and a form checking and feedback module, wherein the identity authentication module is used for carrying out legality authentication on the identity of a user of the train fault overhaul terminal system; the system initialization module is connected with the identity authentication module and is used for obtaining and initializing system permission which the user possesses when the user of the train fault overhaul terminal system passes identity authentication; the fault picture processing module is used for reading and marking train fault pictures obtained in advance; the form editing and submitting module is used for correlating information related with the fault pictures with the pictures, editing the information ...

Vector control device for induction motor

The invention discloses a vector control device for an induction motor and relates to a vector control device without speed sensor for the induction motor. The invention solves the problem of the vector control method of the conventional induction motor that a system is unstable in a low-speed power generation state and has a bigger rotating speed observation error under a low-speed condition because a rotating speed adaptive rate cannot guarantee the stability of an algorithm. In the invention, the speed of the motor can be observed by adding the exciting current error between the actual value and observed value of an exciting current and the product of a q axis stator magnetic chain observed value and a variable gain (M) into the general product of the observed current bias and the observed rotor magnetic chain and through a PI regulator; and thus, the speed of the motor can be controlled. The device reduces the low-speed performance of the system considerably and solves the unstable ...

Modularized multi-level bridge arm capacitor voltage balance control method based on alternating-current side current compensation

The invention provides a modularized multi-level bridge arm capacitor voltage balance control method based on alternating-current side current compensation and belongs to the field of bridge arm capacitor voltage balance control of converters. In order to solve the problem that bridge arm capacitor voltage balance control of an existing converter is difficult to perform, upper bridge arm capacitor voltage errors and lower bridge arm capacitor voltage errors of all phases of the converter are in a closed loop, the result is used for adjusting the set alternating-current side current, compensated current reference quantity is controlled, and the alternating-current side current offset is used for suppressing unbalance between the upper bridge arm capacitor voltage and the lower bridge arm capacitor voltage. The upper bridge arm capacitor voltage and the lower bridge arm capacitor voltage of each phase are subjected to statistics, the bridge arm capacitor voltage difference of each phase is ...

Voltage orienting frequency conversion controller for open loop non-speed sensor

The invention relates to a voltage orientation frequency-vary controller of an opening-ring no-speed sensor, and a controlling technology of a sensing motor, which overcomes the problems of the poor loaded capacity and the light loaded oscillation of a motor caused by the influences of the factors of the voltage decrease of a stator resistor, rotating difference frequencies, dead areas, and the like in the low-speed running of the traditional constant-voltage frequency-ratio control. The voltage orientation frequency-vary controller is composed of the following units, i.e. a current sensor, a vector coordinate changing unit, a PI adjustor, a calculating unit of voltage boosting amount, a sliding-frequency calculating unit, a frequency adder, a first operation unit, a second operation unit, a third operation unit, a fourth operation unit, a fifth operation unit, a sixth operation unit and a SVPWM unit. The PI adjustor is used for controlling the no-power current, and the problem of the light-loaded ...

Method and device for controlling energy balance between bridge arms of modularized multi-level converter

The invention provides a method and device for controlling the energy balance between bridge arms of a modularized multi-level converter and relates to the field of control over the energy balance between the bridge arms of modularized multi-level converters. The method and device for controlling the energy balance between the bridge arms of the modularized multi-level converter solve the problem that energy imbalance between the bridge arms of the modularized multi-level converter causes unstable operation of the modularized multi-level converter. According to the method for controlling the energy balance between the bridge arms of the modularized multi-level converter, an alternating-current component is added to a bridge arm circulation, so that a channel of energy exchange between the upper bridge arm and the lower bridge arm is formed, and on the premise that the alternating-current output voltage of the modularized multi-level converter is not influenced, energy balance of the upper ...

Malfunction detection method of incremental encoder

The invention relates to a malfunction detection method of an incremental encoder, which belongs to the malfunction detection field of the encoder, and solves the problems of the prior art that the non-wire-break malfunction of the incremental encoder cannot be detected. An electric pulse signal A and an electric pulse signal B of the incremental encoder, phase difference of which is 90 degrees, are exclusive or to obtain a synchronic clock signal Clock, circuit output states Q2 and Q1 of two JK triggers FF2 and FF1 which are triggered by two rising edges are determined according to the stateof the electric pulse signals A and B at the rising edge time of every two adjacent periods of the Clock, and the malfunction of the incremental encoder is judged according to the output state Q2 andQ1. The method also comprises the detection of a Z pulse signal of the incremental encoder: a Z pulse signal is adopted to preset a cascaded counter so as to count the pulse number which is outputtedby the ...

Method for automatically hoisting torque of universal frequency converter base on active current component

A method for a universal frequency converter to automatically improve torque based on an active current component relates to the frequency converter control technique, and aims to overcome the defects that the calculation method of the starting torque of the universal frequency converter and the load capacity of a low frequency band are complicated, and the magnetic circuit of a stator is easy to be full, thereby causing overcompensation. The method is realized by the following steps: obtaining referenced output voltage E1<*> and a rotation angle Theta1 of a voltage vector according to current running frequency; obtaining active current id according to the rotation angle Theta1 of the voltage vector and the output current iU and iW of an inverter obtained through sampling, thereby further obtaining the compensation amount Vb of a voltage amplitude value; and generating a modulation signal control frequency converter through an SVPWM signal generator according to regulation voltage obtained ...

Hydraulic damping device suitable for measurement-while-drilling instrument

The invention relates to the technical field of design and manufacturing of vibration dampers of underground measurement-while-drilling instruments, in particular to a hydraulic vibration damping device suitable for the measurement-while-drilling instruments, which adopts the principle that disc springs absorb kinetic energy after being compressed to change impact on the measurement-while-drilling instruments in an underground violent vibration environment into stable vibration, so that the measurement-while-drilling instruments are prevented from being damaged. The internal guide shaft can ensure the directional service of the measurement-while-drilling instrument, and by adopting the hydraulic damping device, the service life of the measurement-while-drilling instrument can be greatly prolonged, the measurement precision of the measurement-while-drilling instrument can be greatly improved, the failure rate of a product is greatly reduced, the maintenance cost of the product is effectively ...

H-bridge cascading STATCOM dead-beat control method based on discrete state observer and discrete sliding-mode observer

The invention discloses an H-bridge cascading STATCOM dead-beat control method based on a discrete state observer and a discrete sliding-mode observer, and relates to the H-bridge cascading STATCOM control technology. The H-bridge cascading STATCOM dead-beat control method aims to solve the problem that an existing dead-beat control method must be matched with a good reference current prediction method and a common prediction method needs to be dependent on an accurate mathematical model, so that the existing dead-beat control method is seriously limited in actual application. According to the H-bridge cascading STATCOM dead-beat control method, the discrete state observer is constructed according to a simple mathematical model of an H-bridge cascading STATCOM, and a reference instruction current at a k+1 moment is obtained by means of calculation at a k moment by adopting the prediction function of the discrete state observer, so that dead-beat control is realized in a true sense; the ...

Novel modular multi-level converter topology

The invention provides a novel modular multi-level converter topology, and relates to a modular multi-level converter. The novel modular multi-level converter topology aims to solve the problems that an existing traditional modular multi-level converter is high in capacitor voltage fluctuation amplitude, high in capacitor capacity, low in power density and large in required module number. According to the modular multi-level converter, a connecting mode of an upper power sub-module and a lower power sub-module of the traditional modular multi-level converter is modified, a middle power module is added, the advantages of the traditional modular multi-level converter are kept, and partial defects of a traditional topology are overcome. When the same number of levels is output, the number of modules required by a novel topology is less, and therefore the cost is lowered easily. When load is the same, the capacitor voltage of the novel topology is less in fluctuation, the capacity of a capacitor ...

Output impedance obtaining method and device based on asynchronous generator and rectifier system and readable storage medium

The invention relates to the technical field of ship DC micro-grids, and provides an asynchronous generator and rectifier system-based output impedance acquisition method, which comprises the following steps of: establishing an asynchronous generator mathematical model; establishing an average switching continuity model of the rectifier and the filter; establishing a small signal model of the asynchronous generator and the rectifier; establishing a closed-loop control loop small signal model based on a mode of adopting a vector to control an asynchronous generator; and obtaining a rectifier DC side output impedance expression based on the closed-loop control loop small signal model. Therefore, the output impedance of the asynchronous generator and the rectifier can be accurately obtained, impedance stability analysis can be conveniently carried out on the ship direct-current micro-grid adopting the asynchronous generator, and the stability of the ship direct-current micro-grid is improved ...

Method for inter-phase balance control over direct current side capacitor voltage of cascade h-bridge STATCOM based on modulating wave translation

The invention relates to the field of power systems, in particular to a method for inter-phase balance control over the direct current side capacitor voltage of a cascade h-bridge STATCOM based on modulating wave translation. The method solves the problems that an existing method for balance control over direct current side capacitor voltage of the cascade h-bridge STATCOM is complex in control process, poor in anti-interference performance, low in control accuracy and large in loss of power units, and a system is short in service life. The method comprises the steps that firstly, charging and discharging conditions of capacitors in power units are judged according to the polarity of voltages and currents output by the power units; then the adjusting direction of the duty ratio is given out according to relative end voltages of the capacitors in the power units, and the voltages of the capacitors in the power units tend to be consistent; the inter-phase balance control over the direct current ...

Converter-based DC micro-grid system stability analysis method

The invention relates to the technical field of direct-current micro-grid systems, in particular to a direct-current micro-grid system stability analysis method based on a converter. The method specifically comprises the following steps: acquiring a reference voltage Vref, a load current iload and a direct-current power grid side voltage Vdc corresponding to each converter in a direct-current micro-grid system; establishing an ARX model, inputting the reference voltage Vref and the load current iload as input data and the direct current power grid side voltage Vdc as output data into the ARX model, and performing system identification to obtain a transfer function of each converter; and calculating the transfer function of the DC micro-grid system according to the transfer function of each converter, and analyzing the stability of the system through pole distribution. According to the method, under the condition that commercial converters widely exist in the industrial field, the stability ...

Cascading static synchronous reactive compensator topology with energy exchange unit and control method thereof

The invention discloses a cascading static synchronous reactive compensator topology with an energy exchange unit and a control method thereof, and relates to the power unit capacitor voltage balance control technology of a cascaded reactive compensation device. The cascading static synchronous reactive compensator topology with the energy exchange unit and the control method thereof aim at solving the problems existing in the method adopted by an existing star connection cascade converter for the capacitor voltage unbalance among phases that the output current of the converter changes and breaks the control reliability and extracting of positive and negative sequence components has lowpass filtering and influences the dynamic performance of the cascading static synchronous compensator. The cascading static synchronous reactive compensator topology comprises N-1 power modules which adopt the star connection, and the N is a positive integer; the N power module adopts the energy exchange ...

Exposed drive full online leak sealing hydraulic oil tank

The invention relates to an exposed drive full online leak sealing hydraulic oil tank, belonging to the hydraulic auxiliary device. The cover board of the tank of the invention is provided with an oil filling port and at least one threaded hole, wherein an adapter is installed at the threaded hole; the adapter is connected with a gas bag through a rubber tube assembly; and the oil filling port is provided with an oil-filling end cover. The invention utilizes the volume change inside the gas bag to satisfy that the hydraulic system can absorb or return oil smoothly; the hydraulic oil tank is completely separated from the atmosphere, thus the problem that the exposed hydraulic drive oil tank is easy to pollute is thoroughly solved, the exposed hydraulic drive (control) full online leak sealing hydraulic oil tank can be realized which does not perform external auxiliary pressurizing, makes full use of the advantages of the hydraulic closed system and the hydraulic exposed system, thoroughly ...

Motor vibration suppression method based on imaginary power current compensation

Disclosed is a motor oscillation restraining method based on reactive current compensation, which relates to the intermediate frequency oscillation restraining method during an universal frequency converter adjusting the speed of the motor. The method overcomes the defect that the prior art relies on the motor parameter too much and is not suitable for the universal frequency converter. The method is realized by the following steps: obtain the three-phase current signal output by an inverter bridge through three current sensors; perform coordinate transformation on the three-phase current signal to calculate the reactive current under the rotating coordinate system; filter the reactive current; carry out subtracting, proportioning and differential operation on the filtered reactive current and a reference current by a subtracter and a PD adjuster to obtain a voltage adjusting value; the voltage adjusting value is then input into a voltage signal feedback device for performing subtraction ...

Microgrid short-circuit fault protection method and device based on current change rate difference value

The invention relates to the technical field of tug direct-current power grid relay protection, and provides a micro-grid short-circuit fault protection method based on a current change rate difference value, and the method comprises the steps: continuously collecting current data; setting two sliding windows to record current historical information; fitting current data of the first sliding window according to a fitting formula; the current change rate of the first sliding window is calculated through a fitting formula; obtaining the actuating quantity of longitudinal differential protection according to the current change rate; calculating the sum of the maximum value of the differential current and the mean value of the absolute values of the currents at the two ends of the cable according to the current data of the second sliding window; the braking amount of longitudinal differential protection is obtained according to the sum of the maximum value of the differential current and the ...

U-shaped plastic thin plate molding method used for thin display

The invention discloses a U-shaped plastic thin plate molding method used for a thin display. The method comprises the following steps: preparing a plate, a first mould, a second mould and a positioning piece, wherein the positioning piece is arranged between the first mould and the second mould; placing the plate on the positioning piece; heating the plate; stitching the first mould and the second mould, and bending the plate to be in a U shape; cooling the plate; separating the first mould from the second mould; and detaching the plate from the first mould.

Method for pre-charging of sub-module capacitor of modularized multi-level converter

The invention provides a method for pre-charging of a sub-module capacitor of a modularized multi-level converter and belongs to the field of flexible voltage source converter based high voltage direct current and power electronics. The method for pre-charging of the sub-module capacitor of the modularized multi-level converter solves the problem that an existing method for pre-charging of the sub-module capacitor is prone to causing an overcurrent fault. According to the method for pre-charging of the sub-module capacitor of the modularized multi-level converter, the direct-current-side output voltage of the modularized multi-level converter is controlled to be always equal to a half of the direct-current power voltage, so that the charging current of a bridge arm keeps stable all the time, and therefore the occurrence of the overcurrent fault is avoided in the charging process; the modularized multi-level converter reaches the highest speed in every stage, so that the overall starting ...

Motor vibration suppression method based on reactive current compensation

Malfunction detection method of incremental encoder

The invention relates to a malfunction detection method of an incremental encoder, which belongs to the malfunction detection field of the encoder, and solves the problems of the prior art that the non-wire-break malfunction of the incremental encoder cannot be detected. An electric pulse signal A and an electric pulse signal B of the incremental encoder, phase difference of which is 90 degrees, are exclusive or to obtain a synchronic clock signal Clock, circuit output states Q2 and Q1 of two JK triggers FF2 and FF1 which are triggered by two rising edges are determined according to the state of the electric pulse signals A and B at the rising edge time of every two adjacent periods of the Clock, and the malfunction of the incremental encoder is judged according to the output state Q2 and Q1. The method also comprises the detection of a Z pulse signal of the incremental encoder: a Z pulse signal is adopted to preset a cascaded counter so as to count the pulse number which is outputted by ...

IGBT stuck-open fault diagnosis method for three-phase inverter bridge of frequency converter

An IGBT (insulated-gate bipolar transistor) stuck-open fault diagnosis method for a three-phase inverter bridge of a frequency converter belongs to the technical field of IGBT fault diagnosis of three-phase inverter bridges and solves problem that misdiagnosis is caused in instant load or instant unload when stuck-open fault of IGBTs of an inverter bridge is determined through the Park vector method. The method comprises the following steps: firstly, three phase currents ia, ib and ic of a motor stator used for speed regulation and controlled by the frequency converter are collected; secondly, the three phase currents ia, ib and ic are transformed through discrete Fourier transform to obtain cosine component aj, k and sine component bj, k of direct current component amplitude and fundamental component amplitude of the three phase currents ia, ib and ic; thirdly, the direct current component amplitude is normalized through the fundamental component amplitude to obtain a direct current component ...

IGBT stuck-open fault diagnosis method for three-phase inverter bridge of frequency converter

Intelligent bearing device of ship propulsion shafting based on CPS

The invention discloses a CPS-based ship propulsion shafting intelligent bearing device, and relates to the technical field of ship propulsion shafting, the CPS-based ship propulsion shafting intelligent bearing device comprises a blade, one end of the blade is connected with a propulsion shafting intelligent bearing device, and the propulsion shafting intelligent bearing device is in interactive control connection through an intelligent bearing system control module; the intelligent bearing device of the propulsion shafting comprises a radial intelligent bearing and an axial intelligent bearing, wherein the axial intelligent bearing comprises a magnetic suspension shaft, a rotor, an intelligent stator, a stator winding and an air gap sensor. According to the CPS-based intelligent bearing device for the ship propulsion shafting, the intelligent bearing system collects physical information of an air gap between the stator and the rotor, meanwhile, ship operation environment information is ...

In mold decoration process

The invention discloses an in mold decoration process, comprising the following steps: a plastic film printed with patterns, a first female die, a first male die and a second male die are prepared and the plastic film is arranged on the first female die; the first male die and the first female die are assembled to carry out high-pressure hot forming to form a pit on the plastic film; the first male die and the first female die are separated, without taking the plastic film out of the first female die; a plastic is ejected and formed on the pit on the plastic film to form a semi-finished plastic shell after the second male die and the first female die are assembled; the semi-finished plastic shell is taken down after the first male die and the first female die are separated; and the semi-finished plastic shell is cropped into a finished plastic shell through the cropping process to improve the precision and accelerate the process.

Method for detecting initial position of magnetic pole of rotor of built-in permanent magnetic synchronous motor

The invention provides a method for detecting the initial position of a magnetic pole of a rotor of a built-in permanent magnetic synchronous motor, belongs to the field of motor control, and solves the problems of over-complicated processing, easy occurrence of polarity misjudging, poor practicality and the like existing in the conventional method based on high-frequency signal injection for detecting the initial position of the rotor. The method comprises the following steps: constantly maintaining the stationary state of the rotor; injecting a rotating high-frequency voltage signal into a stator winding; detecting three-phase stator current and converting the three-phase stator current into two-phase static coordinates; acquiring an error signal capable of reflecting position information of the magnetic pole of the rotor through signal processing; adjusting the error signal by using a PI tracker so as to acquire an initial judging value of the position of the magnetic pole of the rotor ...

Method for compensating starting torque of weighting sensor-free elevator traction permanent magnet synchronous motor

The invention discloses a method for compensating the starting torque of a weighting sensor-free elevator traction permanent magnet synchronous motor, and belongs to the field of motors and elevator tractor control. The method solves the problems that the reliability of an elevator system is reduced and cost is increased because the balance of the elevator system before running is kept by a method for acquiring load weight information of the elevator through a weighing sensor. The method comprises the following steps of: initializing pulse number of an incremental photoelectric encoder, and performing pulse counting on positive and reverse rotation of a motor by adopting the incremental photoelectric encoder; comparing the pulse number of the current sampling period with the pulse number of the previous sampling period to acquire a compassion result Delta P; judging the rotating direction of the permanent magnet synchronous motor according to the Delta P; and compensating the starting torque ...

Multi-section punching and shearing die

The invention discloses a multi-section punching and shearing die applied to a die inside decoration shooting technique. The multi-section punching and shearing die comprises a male die, a female die, a lateral punching and shearing mechanism and a position-guiding device. The male die is provided with a projection on which a tridimensional thin valve jacket is arranged, and the male die is provided with at least one male die blade; the female die is positioned above the male die and is provided with a die cavity, when the male die is matched with the female die, the projection and the die cavity can clamp the tridimensional thin valve jacket; the lateral punching and shearing mechanism is provided with at least one punching and shearing blade which is relatively arranged on the lateral surface of the projection and on a slide block; when the punching and shearing blade moves towards the corresponding male die blade, the tridimensional thin valve jacket can be cut by the punching and shearing ...

Method for automatically hoisting torque of universal frequency converter base on active current component

A method for a universal frequency converter to automatically improve torque based on an active current component relates to the frequency converter control technique, and aims to overcome the defects that the calculation method of the starting torque of the universal frequency converter and the load capacity of a low frequency band are complicated, and the magnetic circuit of a stator is easy tobe full, thereby causing overcompensation. The method is realized by the following steps: obtaining referenced output voltage E1<*> and a rotation angle Theta1 of a voltage vector according to current running frequency; obtaining active current id according to the rotation angle Theta1 of the voltage vector and the output current iU and iW of an inverter obtained through sampling, thereby furtherobtaining the compensation amount Vb of a voltage amplitude value; and generating a modulation signal control frequency converter through an SVPWM signal generator according to regulation voltage obtained ...

Method for detecting initial position of magnetic pole of rotor of built-in permanent magnetic synchronous motor

The invention provides a method for detecting the initial position of a magnetic pole of a rotor of a built-in permanent magnetic synchronous motor, belongs to the field of motor control, and solves the problems of over-complicated processing, easy occurrence of polarity misjudging, poor practicality and the like existing in the conventional method based on high-frequency signal injection for detecting the initial position of the rotor. The method comprises the following steps: constantly maintaining the stationary state of the rotor; injecting a rotating high-frequency voltage signal into a stator winding; detecting three-phase stator current and converting the three-phase stator current into two-phase static coordinates; acquiring an error signal capable of reflecting position information of the magnetic pole of the rotor through signal processing; adjusting the error signal by using a PI tracker so as to acquire an initial judging value of the position of the magnetic pole of the rotor ...