91 results about "Space vector modulation" patented technology

The invention is suitable for the technical field of flexible power distribution of a power system, and discloses a modular multilevel converter multi-objective optimization method, system and device based on model predictive control and space vector modulation, and a medium. Obtaining an output current reference value and a circulating current reference value; obtaining a reference voltage vector based on the output voltage reference value, and screening out a plurality of groups of redundant voltage vector sequences through a space vector diagram; performing performance evaluation through rolling optimization by combining each redundant voltage vector sequence with a multi-target cost function to obtain an optimal voltage vector sequence; and on the basis of the optimal voltage vector sequence and the corresponding duty ratio, a switching signal for driving each sub-module switching device of the MMC is generated, and multi-target cooperative control is realized. The three targets of reference output current tracking, circulating current suppression and sub-module capacitor voltage balance are met, and the dynamic response capability, efficiency and reliability of MMC system operation are comprehensively improved.

The invention discloses a flux linkage tracking full-speed-domain high-precision predictive current control method for a permanent magnet synchronous motor, and the method comprises the steps: sampling a phase current signal, a position signal and a speed signal of the permanent magnet synchronous motor, and obtaining a dq sampling current through coordinate transformation; calculating a predicted current according to the established tracking discrete model; the sinusoidal variation characteristic and the dynamic transient characteristic of the resistance voltage drop are accurately considered in the current prediction and reference voltage calculation stage, and the resistance voltage drop is accurately represented through accurate feed-forward compensation of predicted current and reference voltage; a driving signal of the inverter is obtained through coordinate transformation and space vector modulation, and full-speed-domain high-precision fast-response current prediction control over the permanent magnet motor is achieved. According to the method, the current flow steady state control error caused by the model error is reduced, the current control precision and the dynamic response performance of the permanent magnet synchronous motor in the full-speed domain are effectively improved, and a high-precision model basis is provided for high-precision position-free control and parameter online identification.

The invention relates to the technical field of motor control, and particularly provides a control method and system suitable for a one-way running motor of a two-wheeled electric vehicle. The method aims to solve the problems of unstable motor operation and insufficient reliability caused by torque pulsation in the prior art. The method comprises the following steps: executing off-line identification of motor parameters to obtain initialized parameters; multi-source operation state signals are collected, and a vehicle working condition judgment result is obtained through fusion analysis; performing fault diagnosis and grading evaluation to form a fault-tolerant instruction; dynamic dead zone compensation and self-adaptive overmodulation are implemented by combining the parameters and the working conditions, and an optimization control instruction is output; generating a PWM driving signal through space vector modulation; and responding to the fault-tolerant instruction, and fusing a sensorless algorithm and a health sensor signal to realize degraded operation. According to the invention, the smoothness and efficiency of motor operation and the fault-tolerant capability of the system are effectively improved.

The invention relates to the technical field of voice recognition and intelligent household electrical appliance control, in particular to an induction cooker control method based on voice recognition, which comprises the following steps: synchronously acquiring a voice signal and a lip motion signal, and generating multi-modal sensing data through timestamp alignment; performing cross-modal anti-noise processing on the data, and outputting a fusion feature tensor fusing acoustic and visual features; semantic analysis and danger instruction recognition are executed, and a risk filtering control instruction containing temperature / fire parameters is generated; calling a thermodynamic dynamic model to calculate a power control parameter based on the instruction parameter; converting a power parameter into a space vector modulation waveform to drive a load circuit, and synchronously collecting the pot bottom temperature; and triggering an anti-noise process and thermodynamic model parameter updating according to the deviation between the actual temperature and the target temperature. Noise interference is reduced through multi-modal signal cross validation, dangerous instructions are intercepted in combination with knowledge graph constraints, the noise suppression capability and the temperature control precision are continuously optimized, and the safety and reliability of voice control in a complex environment are improved.

The invention relates to the technical field of generator control, and discloses an intelligent vehicle-mounted high-power self-generating control method and system. The method comprises the following steps: acquiring operating parameters of a generator set, performing high-precision digital processing, realizing constant-rotating-speed control through cooperation of multiple controllers based on a rotating-speed fluctuation characteristic value, performing power factor correction through coordinate transformation and active rectification to obtain a direct-current bus voltage, performing precise voltage stabilization by adopting a multi-phase interleaving converter, and outputting the direct-current bus voltage. And finally, outputting a high-quality three-phase alternating-current power supply through space vector modulation and closed-loop feedback control. The technical problems in the prior art that the power supply quality control capability is insufficient, the intelligent level is low, the environmental adaptability is poor, the load adaptability is limited, and the maneuverability is limited are solved.

The invention provides an SVG current adjustment method and system of a photovoltaic power station, and belongs to the technical field of SVG current adjustment. The method comprises the following steps: acquiring a current signal and a voltage signal based on a transformer deployed by SVG; calculating the current deviation, and analyzing the voltage fluctuation condition based on the collected voltage signal to predict the operation state of the power grid; selecting an SVG current adjustment strategy according to the calculated current deviation and the predicted power grid operation state; generating a corresponding adjustment instruction by using the selected SVG current adjustment strategy; and according to the adjustment instruction, controlling the switching action of a power device of the SVG so as to adjust the output current of the SVG. According to the invention, through various SVG current adjustment strategies, the method can adapt to working conditions and current deviation so as to ensure the stability and accuracy of SVG output current; through feedforward decoupling control and a space vector modulation technology, rapid and stable execution of an instruction is ensured, power consumption is reduced, and service life attenuation of equipment is inhibited.

The invention belongs to the technical field of motor driving control, and discloses a space vector modulation strategy method for a permanent magnet synchronous motor, which comprises the following steps of: searching a region division and vector arrangement table by using regions in which Vlp and V are positioned to obtain an optimal vector sequence, and arranging vectors based on a principle of eliminating a peak of a CMV and minimizing switching operation times; and finally, calculating the duty ratio of a plurality of effective voltage vectors used for synthesizing the next period according to the amplitude-second balance principle. Compared with a control strategy that only one effective vector or two adjacent effective vectors are used in each control period, the virtual vector synthesized by the method is the same as the reference vector, and common-mode voltage spikes can be eliminated by the method; compared with NSPWM and AZPWM, the method has the advantages that area division and vector sorting are reasonably arranged, so that the switching action times are minimized, the switching loss is reduced, and the inverter efficiency is improved.

The invention discloses a three-phase three-wire three-level hybrid modulation switching method and device and a medium, and the method comprises the following steps: obtaining a three-phase sinusoidal modulation wave, and superposing a primary common-mode voltage to obtain a continuous first modulation wave; if the continuous space vector control is executed, comparing the first modulated wave with a carrier wave to form a first duty ratio signal; if the intermittent space vector control is executed, superposing the first modulation wave and a secondary common mode voltage based on a unified coefficient to obtain an intermittent second modulation wave; and according to a specific mode of intermittent space vector modulation, assigning a value to the unified coefficient to obtain a corresponding target intermittent space vector modulation wave. The device and the medium are both used for implementing the method. The method has the beneficial effects that the degree of freedom of the algorithm can be maximized through a PWM unification and coefficient modulation strategy; compared with a traditional mode, the complexity of an algorithm can be effectively reduced, and the reliability of overall code execution can be improved.

The invention discloses a current-limiting control method based on a network-forming static var generator. The current-limiting control method comprises the following steps: inputting an external direct-current voltage, stabilizing the voltage by a capacitor, and then outputting the voltage to an inverter bridge; the inverter bridge generates controllable alternating current through space vector modulation; the inductive filter filters high-frequency harmonic output end voltage; the terminal voltage amplitude and phase are monitored in real time, and current-limiting control is triggered based on the phase deviation between the voltage and the virtual internal potential when the voltage of the power grid drops; the terminal voltage interacts with ideal power grid voltage at a common coupling point through power grid impedance to generate PCC voltage; pCC voltage and output current are detected, and instantaneous power is calculated; the power signal is filtered and de-noised and then a modulation instruction is generated by the current-limiting controller and is fed back to the inverter bridge to form a closed loop. The reactive power supporting voltage is injected preferentially, the voltage drop amplitude is remarkably reduced, the inertia damping supporting capacity of the system is enhanced, power grid fault recovery is accelerated, and meanwhile the voltage instability problem caused by a traditional current limiting strategy is avoided.

The invention relates to a space vector modulation method based on a single-phase parallel current source inverter, and the method comprises the following steps: 1, constructing a single-phase parallel current source inverter circuit, and dividing all current vectors of the single-phase parallel current source inverter according to different amplitudes of output current Iw; 2, analyzing the influence of the small-current vector redundant switching state on the direct current, and constructing a small-current vector switching state selection strategy; 3, analyzing the influence of the zero-current vector redundant switching state on the direct current, and constructing a zero-current vector switching state selection strategy; and step 4, in each sampling period, synthesizing a reference current vector Iref by two static current vectors which are closest to each other according to an ampere-second balance principle, collecting a power grid voltage us and direct currents i1-i4 at the same time, and selecting a redundant switch state according to the strategies in the step 2 and the step 3 to realize the current balance of the direct current bridge arm. According to the invention, the waveform quality of the grid-connected current can be improved.

This invention relates to the field of inverter technology, and particularly to a heterogeneous power device hybrid inverter and its space vector modulation method. The heterogeneous power device hybrid inverter provided in this invention includes a first constant current source, a second constant current source, a main power inverter module, a secondary power inverter module, and a capacitive reactance module. The first constant current source is connected to the main power inverter module to provide current to the main power inverter module. The main power inverter module includes multiple silicon-based insulated-gate bipolar transistors (SBMTs) as main switching transistors, and the main power inverter module is connected to the capacitive reactance module. The second constant current source is connected to the secondary power inverter module to provide current to the secondary power inverter module. The secondary power inverter module includes multiple silicon carbide-based metal-oxide-semiconductor field-effect transistors (MOSFETs) as secondary switching transistors, and the secondary power inverter module is connected to the capacitive reactance module. The heterogeneous power device hybrid inverter and its space vector modulation method provided by this invention can balance high inverter frequency and low switching losses.

The application discloses a permanent magnet synchronous motor model prediction torque control method based on a hybrid mode optimization. The method first constructs a reference voltage vector through a torque error target function and a discretization prediction model of the permanent magnet synchronous motor, and then designs a hybrid mode optimization algorithm. The algorithm first designs a double-vector mode optimization on the sector boundary of a voltage space vector diagram, and then designs a three-vector optimization mode based on a discrete space vector modulation inside the sector. The optimal synthesized voltage vector obtained by the hybrid mode optimization algorithm is transmitted to a voltage error target function to realize the switching of the two modes, so that the control execution mode and the optimal synthesized voltage vector are determined. The control method disclosed by the application has high freedom to adjust the amplitude and position of the synthesized voltage vector, and thus has high steady-state performance of the control system and fast torque dynamic response in the full speed range.

The invention provides a down-sampling repetitive controller applied to a three-phase four-leg inverter, and the controller comprises an ADC sampling unit which is used for sampling an output phase voltage and an inductive current of the three-phase four-leg inverter at a switching frequency F (S), and converting the output phase voltage and the inductive current into an alpha beta 0 reference system through Clark transformation; the repetitive control unit is used for subtracting the output phase voltage and the inductive current after the Clark transformation from a reference voltage and a reference current to obtain an error voltage signal and an error current signal, applying the error voltage signal and the error current signal to an RC (Resistance-Capacitance) circuit, and performing down-sampling according to a preset proportion; and performing state feedback control on the output of the RC circuit so as to generate a three-dimensional space vector modulation component to act on the three-phase four-leg inverter. The method has the advantages that (1) a closed-loop system pole is arranged by using a state feedback strategy to stabilize the system, so that LPF does not need to be introduced; and (2) designing an integer phase lead compensator.

The invention relates to a model prediction control method and device for dynamically adjusting a prediction range. The method comprises the following steps: performing one-beat delay compensation on a motor system according to sampled data, and adjusting a prediction range of the one-beat delay compensation according to an actual switching frequency of the motor system at the current moment and a preset target switching frequency; calculating a reference voltage vector of the motor system based on a current dead-beat control principle, and performing space vector modulation on the reference voltage vector based on a volt-second balance principle to obtain a plurality of candidate voltage vector sequences; and selecting the candidate voltage vector sequence with the minimum harmonic current effective value as an optimal voltage vector sequence, and controlling the action of the motor system at the future moment according to the optimal voltage vector sequence. According to the method provided by the invention, the current harmonic is relatively small by adjusting the prediction range, limiting the switching frequency and screening the voltage vector sequence, so that the steady-state performance of the motor system is improved.

This invention proposes an innovative model predictive control-based current control method and system for permanent magnet synchronous motors (PMSMs), aiming to address the problems of slow dynamic response and low control accuracy in traditional control methods when facing parameter variations and external disturbances. By constructing an accurate mathematical model, this invention not only improves the dynamic response speed and control accuracy of the motor but also significantly reduces torque ripple, thereby enhancing the stability and reliability of motor operation. Furthermore, the introduction of intelligent algorithms such as neural networks or fuzzy logic, as well as adaptive control algorithms, further enhances the system's adaptability and robustness. The application of space vector modulation technology optimizes the current waveform, further reducing torque ripple and improving the smoothness of motor operation. The control method of this invention is suitable for industrial applications with extremely high requirements for dynamic performance and control accuracy, demonstrating its broad application potential in the field of modern industrial motor control.

A method (100) for operating an inverter (1) wherein the inverter selectively connects three AC phases (U, V, W) of an inductive load (4) to the positive or negative terminal of a DC voltage (2) provided at the input terminal (1a) of the inverter (1) by manipulating switching elements (3a-3f) arranged in three half-bridges (5a-5c), wherein the switching state (110) of the switching elements (3a-3f) is changed by rotating space vector modulation, wherein, additionally, when the space vectors (6a-6f) having the same switching state of the corresponding switching elements (3a, 3d; 3b, 3e; 3c, 3f) of at least one half-bridge (5a-5c) are modulated, such half-bridges (5a-5c) remain completely off (120).

A power converter and a circuit arrangement. The power converter has a series circuit, including first and second intermediate circuit capacitors, connected in parallel to first and second half-bridges. A first terminal of a first center switch is connected to a center point of the first half-bridge and is configured to provide a first phase. A first terminal of a second center switch is connected to a center point of the second half-bridge of the power converter and is configured to provide a second phase. A second terminal of the first center switch and of the second center switch are connected and configured to provide a third phase. An evaluation unit is configured to actuate the first and second half-bridges, the first center switch, and the second center switch based on a space vector modulation and to adjust a voltage ratio between the first and second intermediate circuit capacitors.

The invention provides a fault-tolerant control method for an open-circuit fault of a single switch tube of a five-phase permanent magnet synchronous motor. The method comprises the following steps: deducing each phase voltage according to a fault position and reconstructing a space voltage vector; then a virtual voltage vector is generated by applying a discrete space vector modulation technology so as to expand a candidate vector set, and optimization is carried out through sector division; a third harmonic current is reduced by setting a specific segmented given current; and finally, by constructing a voltage error value function, a current prediction step in traditional model prediction is omitted, and an optimal voltage vector is directly selected to generate a PWM signal. According to the method, the torque ripple and the current harmonic can be effectively suppressed without modifying a motor mathematical model and a reduced-order transformation matrix, and the method has high dynamic performance and good universality.

The invention discloses a state-of-charge balance control method and device and a medium, and the method comprises the steps: carrying out the calculation of the target three-phase adjustment power through the working voltage and working current of each phase in a direct-hanging type energy storage system, and the current charging and discharging power, carrying out the fundamental wave zero-sequence voltage conversion based on the target three-phase adjustment power, and carrying out the balance control of the state-of-charge. And the target zero-sequence voltage is injected into the three-phase modulation voltage after space vector modulation, so that real-time balance control over the three-phase charge state under the unbalanced working condition of the power grid is achieved, the control effect is improved, the zero-sequence voltage injection range is increased, and the control precision is improved. And the control speed for realizing the equilibrium state is improved.

The invention discloses a grid-connected inverter electric energy quality optimization control method for power grid voltage sag, which comprises the following steps: performing parameter preprocessing on a pre-established mathematical model of a grid-connected inverter to obtain preprocessing parameters under a two-phase static coordinate system; calculating a positive sequence voltage component and a negative sequence voltage component, and calculating an initial current reference instruction under various electric energy quality optimization modes according to an instantaneous power theory; performing dynamic correction and amplitude limiting on the initial current reference instruction based on the voltage drop depth and the low voltage ride through requirement, and generating a final current reference instruction for model prediction control; predicting a system state of a next sampling period based on the mathematical model and the preprocessing parameters, and constructing a value function by taking tracking of a final current reference instruction as a control target based on the system state; and solving an optimal inverter valve side voltage control quantity through the value function, and applying the control quantity to space vector modulation so as to drive the grid-connected inverter.

A control system for a multiphase brushless motor without a position sensor, incorporating drive control electronics, comprising: a switching means, provided with two-state switches for varying the electrical voltage applied to each of the phases; a means for detecting overloading of the motor; and a means for determining an operating point, allowing at least two operating points to be applied, the control electronics being arranged to use space vector modulation or vector modulation to generate a sinusoidal waveform from a DC voltage, and the control electronics being arranged to modify the operating point at least once if an overload is detected by the overload detection means.

The invention relates to a high-efficiency energy router protection and control method based on an ANPC topological structure. The method comprises the following steps: acquiring operation condition data, constraint parameter data and midpoint voltage ripple data corresponding to the rail transit system; zero-payload zero-momentum coding is carried out on space vector modulation output under ANPC, and a three-level self-conservation sequence and a time mark cache index are generated; performing congruence interlacing reconstruction on the power echo according to the index to obtain equivalent super-sampling echo matrix data; performing conformal scattering chromatography on the matrix data, and outputting distance branch reflection distribution data and positioning coordinate initial value data; performing persistent coherence type judgment on the reflection distribution data to obtain abnormal form data; and fusing the initial value data of the positioning coordinates and the abnormal form data to develop a zero-regret game planning linkage strategy, and generating position action protection data to control the energy router. By adopting the method, the protection and control toughness of the energy router can be effectively ensured.

The application relates to the technical field of electromechanical control, and discloses a torque ripple suppression method and system for an electric drive axle based on active disturbance rejection control. The method comprises the following steps: obtaining three-phase currents, a motor speed and a target torque value of the electric drive axle; transforming the three-phase currents to obtain a cross-axis current feedback of the electric drive axle; performing frequency band separation on the cross-axis current feedback by taking a mechanical cutoff frequency corresponding to the motor speed and an electrical harmonic frequency as filter parameters to obtain disturbance observation values; performing weighted summation on compensation values of the mechanical disturbance observation values and compensation values of the electrical harmonic observation values to obtain a comprehensive feedforward compensation value; scaling a motor torque constant based on the target torque value to obtain a cross-axis current reference value; and performing space vector modulation on the comprehensive feedforward compensation value and the cross-axis current reference value to obtain a switching control sequence of the electric drive axle. The application can improve the precision of torque ripple suppression for an electric drive axle based on active disturbance rejection control.

The invention discloses a high-power three-level switching power supply and a control method, and relates to the technical field of power electronic conversion and control. The power supply comprises a control core unit, an acquisition monitoring unit and a three-level power conversion unit which adopts a diode clamping topological structure and comprises a silicon carbide device. And the control core calculates the feedback signal to generate a reference voltage vector based on an active-disturbance-rejection control algorithm in combination with a power feed-forward strategy, generates a driving signal by adopting a four-section space vector modulation strategy, and controls the on-off of a switching tube to adjust power output. The invention has the advantages of high power density, fast dynamic response, low output ripple, easy integrated control and the like.

The application discloses a kind of self-adaptive damping multi-resonance suppression methods of large-scale off-grid light hydrogen storage system, comprising:1.Sampling bridge arm side inductance current, error signal is obtained by subtracting given signal from bridge arm side inductance current;2.Error signal is obtained after sliding mode control;3.Output signal is obtained after damping adjustment unit;4.According to the difference of multi-machine parallel working condition, the adaptive adjustment of damping is carried out;5.The modulated signal is sent into space vector modulation unit, and the pulse driving signal of each switching device is output.The application can solve the multi-resonance problem of grid-connected inverter current loop, ensure the stable operation of system while improving dynamic response, and has important theoretical significance and practical value.

The invention relates to the technical field of energy storage control, in particular to an energy storage converter and a control method, and the method comprises the following steps: extracting a voltage gradient trend, identifying response delay change, matching a control state label, issuing a space vector modulation command, and obtaining a control scheme. According to the method, voltage trend identification is realized through pairing judgment of a voltage gradient proportion and a fluctuation tolerance range, a dynamic adjustment change trend is identified through a weekly forward delay differential proportion, quantitative evaluation of an adjustment response degree is realized, a path control state matching mechanism is established according to trend identification and response change parameters, and a path control state matching mechanism is established. The over-modulation risk is effectively recognized and judged and marked, space vector instruction adjustment is driven through a mark label, dynamic correction regulation and control of the voltage control path of the energy storage system are achieved, the recognition capacity of the voltage disturbance state is improved, and the energy storage output stability and the adjustment path reasonability are guaranteed. And the control strategy adaptability of the energy storage converter in an unsteady state scene is enhanced.

The invention discloses a self-adaptive predictive control method for a synchronous reluctance motor system with a sine wave filter, and belongs to the field of motor control. The method comprises the following steps: sampling information of a synchronous reluctance motor system with a sine wave filter at a k moment, and establishing a fixed parameter prediction model of the system by adopting a first-order Runge-Kutta discrete method; establishing a self-adaptive prediction model of the system, constructing a self-adaptive parameter estimation function, and solving a self-adaptive parameter estimation law according to a minimum value principle; filtering inductive current least-beat prediction control is carried out on the self-adaptive prediction model, and an obtained self-adaptive prediction control instruction is input into a band elimination filter to realize resonance suppression; and performing synchronous rotation inverse transformation on the self-adaptive prediction control instruction, and then sending the self-adaptive prediction control instruction to a space vector modulation generation pulse to act on an inverter switching tube so as to realize self-adaptive prediction control. Compared with a traditional predictive control method, the method is easy to implement and has high robustness and stability for model parameter mismatch.

The invention relates to a method for regulating and / or controlling an electric machine by extended synchronous modulation based on space vector modulation, wherein the following input variables are used: - a set (Σ) of switching durations (Σ1, ..., Σx) that appear within a subsequent sampling interval, - a current angular error (ΣError,Now) and a subsequent angular error (ΣError,Next), - a minimum switching angle (Σmin), wherein an online calculation of switching angles (Σ1) and a flow trajectory (Σab) is performed, wherein pulse patterns (suvw(Σel)) are calculated online as a function of a modulation level (m).

This invention discloses a method for equalizing capacitor voltage in an MMC submodule based on space vector modulation. Firstly, in... α ' β The invention implements spatial vector modulation (MMC) in a coordinate system, locates the sector triangle containing the reference vector, calculates the action time of the three vertex vectors of the sector triangle that synthesize the reference vector, and determines the corresponding switching state sequence between the three vertex vectors of the sector triangle based on a five-segment algorithm. Then, based on the calculated number of submodules to be engaged in each phase's upper and lower arms, the direction of the arm current, and the maximum, minimum, second maximum, and second minimum capacitor voltage values ​​in the engaged and disengaged submodule groups, the specific engaged or disengaged submodules are determined. The capacitor voltage equalization control method proposed in this invention is simple to implement, unaffected by the number of arm submodules, avoids capacitor voltage sequencing, and ensures precise synchronization between spatial vector modulation and capacitor voltage equalization control.

The invention relates to the technical field of motor control, in particular to a low-speed large-torque control method and system for an industrial robot joint motor, and the method comprises the steps: collecting the voltage of a DC bus, each phase of current of a stator, and the position and rotating speed of a rotor, and carrying out the coordinate transformation of each phase of current of the stator according to the position of the rotor; obtaining d-axis current and q-axis current of the synchronous rotating coordinate system; solving a stator flux linkage estimation value and an electromagnetic torque estimation value according to the d-axis current, the q-axis current and preset motor parameters, and generating a torque error and a flux linkage error; the torque error passes through a torque regulator to obtain a load angle instruction, and the flux linkage error and the rotating speed pass through a flux linkage regulator to obtain a voltage vector amplitude instruction and a voltage vector angle instruction; generating a d-axis voltage instruction and a q-axis voltage instruction; constructing an inverter nonlinear voltage disturbance estimation model, defining d-axis disturbance voltage and q-axis disturbance voltage as disturbance voltage states, and merging the disturbance voltage states into an extended Kalman filtering state space model; executing extended Kalman filtering prediction and correction to obtain a d-axis disturbance voltage estimated value and a q-axis disturbance voltage estimated value; forming a voltage compensation amount and superposing the voltage compensation amount to obtain a compensation voltage instruction; driving pulses are generated through inverse coordinate transformation and space vector modulation, and low-speed large-torque online compensation is achieved. According to the invention, the problems that the output pole voltage of the joint motor of the industrial robot has unexpected distortion and further shows control nonlinearity and the distortion voltage is difficult to directly sense and measure can be solved.