阅读说明：本技术 一种基于电参量重构的电机输出扭矩估算方法 (Motor output torque estimation method based on electrical parameter reconstruction ) 是由 黄银国 李潇 聂晶晶 郑叶龙 赵美蓉 于 2020-05-20 设计创作，主要内容包括：一种基于电参量重构的电机输出扭矩估算方法,包括分别通过直流电压传感器和直流电流传感器采集与电机相连的三相整流-逆变系统直流母线上的电压信号和电流信号,通过电动机的矢量控制产生PWM信号来控制逆变器三相桥臂的开关状态,跟据三相桥臂开关状态重构出三相整流-逆变系统输出端三相交流电压信号和电流信号,根据重构出的三相交流电压信号和电流信号,进行三相逆变系统的有功功率计算,再通过重构出的有功功率和电动机的转速来进行电动机扭矩的计算。本发明通过交流侧重构来得到三相电压电流,避免了使用多个交流传感器,降低了系统复杂度,减小了系统误差,且适合集成化,简单易行,可以应用到工业现场。(A motor output torque estimation method based on electric parameter reconstruction includes collecting voltage signals and current signals on a direct current bus of a three-phase rectification-inversion system connected with a motor through a direct current voltage sensor and a direct current sensor respectively, generating PWM signals through vector control of the motor to control the on-off state of a three-phase bridge arm of the inverter, reconstructing three-phase alternating current voltage signals and current signals at the output end of the three-phase rectification-inversion system according to the on-off state of the three-phase bridge arm, calculating active power of the three-phase inversion system according to the reconstructed three-phase alternating current voltage signals and current signals, and calculating motor torque according to the reconstructed active power and the rotating speed of the motor. According to the invention, three-phase voltage and current are obtained through alternating current side reconstruction, so that the use of a plurality of alternating current sensors is avoided, the system complexity is reduced, the system error is reduced, and the method is suitable for integration, simple and feasible and can be applied to industrial fields.)

1. A motor output torque estimation method based on electric parameter reconstruction is characterized by comprising the steps of collecting voltage signals and current signals on a direct current bus of a three-phase rectification-inversion system connected with a motor through a direct current voltage sensor and a direct current sensor respectively, generating PWM (pulse width modulation) signals through vector control of the motor to control the switching state of a three-phase bridge arm of the inverter, reconstructing three-phase alternating current voltage signals and current signals at the output end of the three-phase rectification-inversion system according to the switching state of the three-phase bridge arm, calculating active power of the three-phase inversion system according to the reconstructed three-phase alternating current voltage signals and current signals, and calculating motor torque according to the reconstructed active power and the rotating speed of the motor.

2. The method for estimating the output torque of the motor based on the electrical parameter reconstruction as claimed in claim 1, wherein the reconstruction of the three-phase alternating voltage signal at the output end of the three-phase rectification-inversion system according to the switching state of the three-phase bridge arm is performed according to the following formula:

wherein, T₁、T₂、T₃Respectively representing a period T_sInstantaneous phase voltage duty ratio given by three power tubes of the inner upper half bridge is given; v_dRepresenting the voltage on the dc bus; u shape_an、U_bn、U_cnThe reconstructed phase a, phase B and phase C voltages are shown.

3. The method for estimating the output torque of the motor based on the electrical parameter reconstruction as claimed in claim 1, wherein the reconstruction of the three-phase alternating current signal at the output end of the three-phase rectification-inversion system according to the switching states of the three-phase bridge arms is performed according to the corresponding relationship between the direct current side current and the alternating current side current of the inverter under different switching states of the three-phase bridge arms of the inverter:

(1) when the bridge arm switch state is 100, the direct current bus current corresponds to + A phase current + i_a(ii) a When the bridge arm switch state is 101, the direct current bus current corresponds to the phase-B current (-i)_b) (ii) a When the bridge arm switch state is 001, the direct current bus current corresponds to + C phase current (+ i)_c) (ii) a When the bridge arm switch state is 011, the direct current bus current corresponds to the phase-A current (-i)_a) (ii) a When the bridge arm switch state is 010, the direct current bus current corresponds to + B phase current (+ i)_b) (ii) a When the bridge arm switch state is 110, the DC bus current pairShould be-C phase current (-i)_c) (ii) a When the bridge arm switch states are 000 and 111, the direct current bus current does not correspond to any phase current;

(2) first, any two-phase current is obtained according to i_a+i_b+i_cAnd obtaining a third phase current when the three-phase current is 0, namely reconstructing a three-phase alternating current signal.

4. The method for estimating the output torque of the motor based on the electrical parameter reconstruction as claimed in claim 1, wherein the active power calculation of the three-phase inverter system is to calculate the active power P output to the motor according to the reconstructed three-phase ac voltage signal and current signal and the phase difference therebetween, and the formula is as follows:

wherein the content of the first and second substances,

5. A method of estimating output torque of an electric machine based on electrical quantity reconstruction as claimed in claim 1 wherein said calculating of motor torque comprises:

(1) the calculation formula of the motor rotating speed N is obtained by the encoding number m of the encoder arranged on the motor shaft and the detection of the pulse number N output by the encoder per second as follows:

(2) according to the rotating speed n of the motor and the reconstructed active power P, the motor torque T is obtained by adopting the following formula:

Technical Field

The invention relates to a motor output torque. In particular to a motor output torque estimation method based on electrical parameter reconstruction.

Background

The load simulation test system is a system for performing dynamic simulation on an actual load, wherein the electrodynamic type load simulation test system has the advantages of large energy volume ratio, possible feedback, fast dynamic response, high reliability and the like, the test platform has universality, and a control strategy of the test platform can be applied to load simulation of any target, and the test platform is a research hotspot at home and abroad.

The electric load simulation test system uses the motor as a device for exchanging energy between mechanical energy and electric energy. The target equipment is loaded in the form of expression of torque, and then the simulation of the actual load is realized, and the actual load is a torque servo control system. In the load simulation test system, the processing and control of the motor torque are important parts. At present, the torque of the motor is mainly controlled in two ways, one is a direct torque control way, and the other is a traditional vector control way. In direct torque control, since the difference between the calculated torque value and the torque command will directly participate in the formation of the command, it can be seen that accurately calculating the torque value is a basic requirement for achieving good control thereof. In the conventional vector control, although the calculated value of the torque does not participate in the control algorithm, in order to improve the torque ripple phenomenon, the calculated value of the torque can be fed back, and the subsequent current command is compensated according to the difference value between the calculated value of the torque and the torque command, so that the closed-loop control of the torque is formed, and therefore, the real-time estimation of the motor torque is very important.

Disclosure of Invention

The invention aims to solve the technical problem of providing a motor output torque estimation method based on electrical parameter reconstruction, which can reduce the complexity of a system and reduce system errors.

The technical scheme adopted by the invention is as follows: a motor output torque estimation method based on electric parameter reconstruction includes collecting voltage signals and current signals on a direct current bus of a three-phase rectification-inversion system connected with a motor through a direct current voltage sensor and a direct current sensor respectively, generating PWM signals through vector control of the motor to control the on-off state of a three-phase bridge arm of the inverter, reconstructing three-phase alternating current voltage signals and current signals at the output end of the three-phase rectification-inversion system according to the on-off state of the three-phase bridge arm, calculating active power of the three-phase inversion system according to the reconstructed three-phase alternating current voltage signals and current signals, and calculating motor torque according to the reconstructed active power and the rotating speed of the motor.

The three-phase alternating voltage signal of the output end of the three-phase rectification-inversion system is reconstructed according to the switching state of the three-phase bridge arm according to the following formula:

wherein, T₁、T₂、T₃Respectively representing a period T_sInstantaneous phase voltage duty ratio given by three power tubes of the inner upper half bridge is given; v_dRepresenting the voltage on the dc bus; u shape_an、U_bn、U_cnThe reconstructed phase a, phase B and phase C voltages are shown.

The reconstruction of the three-phase alternating current signal of the output end of the three-phase rectification-inversion system according to the switching states of the three-phase bridge arms is obtained according to the corresponding relation between the direct current side current and the alternating current side current of the inverter under different switching states of the three-phase bridge arms of the inverter:

(1) when the bridge arm switch state is 100, the direct current bus current corresponds to + A phase current + i_a(ii) a When the bridge arm switch state is 101, the direct current bus current corresponds to the phase-B current (-i)_b) (ii) a When the bridge arm switch state is 001, the direct current bus current corresponds to + C phase current (+ i)_c) (ii) a When the bridge arm switch state is 011, the direct current bus current corresponds to the phase-A current (-i)_a) (ii) a When the bridge arm switch state is 010, the direct current bus current corresponds to + B phase current (+ i)_b) (ii) a When the bridge arm switch state is 110, the direct current bus current corresponds to the-C phase current (-i)_c) (ii) a When the bridge arm switch states are 000 and 111, the direct current bus current does not correspond to any phase current;

(2) first, any two-phase current is obtained according to i_a+i_b+i_cObtaining the third phase current when the third phase current is 0, namely reconstructing threeAn alternating current signal.

The active power calculation of the three-phase inverter system is to calculate the active power P output to the motor according to the reconstructed three-phase alternating voltage signal and current signal and the phase difference between the two signals, and the formula is as follows:

wherein the content of the first and second substances,

for reconstructing the three-phase voltage-current phase difference of the output terminal, I_nAnd U_nRespectively are a three-phase alternating current signal and a voltage signal which are reconstructed.

The calculating of the motor torque comprises the following steps:

(1) the calculation formula of the motor rotating speed N is obtained by the encoding number m of the encoder arranged on the motor shaft and the detection of the pulse number N output by the encoder per second as follows:

(2) according to the rotating speed n of the motor and the reconstructed active power P, the motor torque T is obtained by adopting the following formula:

the invention discloses a motor output torque estimation method based on electric parameter reconstruction, which realizes the calculation of the mechanical torque of a motor on the basis of performing active power calculation by adopting the reconstruction of the voltage and the current of the alternating current side of an inverter. According to the invention, the direct current sensors are adopted to measure the voltage and the current of the direct current bus, and the three-phase voltage and the current are obtained through the reconstruction of the alternating current side, so that the use of a plurality of alternating current sensors is avoided, the system complexity is reduced, the system error is reduced, and the method is suitable for integration. The method completes the estimation of the motor torque on the basis of reconstruction, avoids the problem that the output power shaft is connected with a torque sensor in series, can be applied to industrial fields, is simple and easy to implement, and has very high practical significance.

Drawings

FIG. 1 is a functional block diagram of a method for estimating torque of an electric machine according to an embodiment of the present invention;

fig. 2 is a circuit diagram of system hardware according to an embodiment of the present invention.

Detailed Description

The following describes a method for estimating motor output torque based on electrical parameter reconstruction according to the present invention in detail with reference to the following embodiments and the accompanying drawings.

The invention discloses a motor output torque estimation method based on electrical parameter reconstruction, which comprises the steps of collecting voltage signals and current signals on a direct current bus of a three-phase rectification-inversion system (AC-DC-AC system) connected with a motor through a direct current voltage sensor and a direct current sensor respectively, generating PWM (pulse width modulation) signals through vector control of the motor to control the switching state of a three-phase bridge arm of an inverter, reconstructing three-phase alternating current voltage signals and current signals at the output end of the three-phase rectification-inversion system according to the switching state of the three-phase bridge arm, calculating the active power of the three-phase inversion system according to the reconstructed three-phase alternating current voltage signals and current signals, and calculating the torque of the motor according to the reconstructed active power and the rotating speed of the motor.

As shown in fig. 1, an alternating current power supply is switched on to supply power to a system, the rectification module is used for realizing the AC-DC conversion of signals, and the inverter module is used for realizing the DC-AC conversion of signals into the motor for supplying power; the method comprises the steps that a direct current sensor and a direct current voltage sensor are utilized on a direct current bus to complete the acquisition of voltage and current signals of a direct current side of an inverter, voltage and current signals flowing out of the inverter are obtained through reconstruction, and the active power output to a motor by the inverter can be further calculated; the motor drives the load to rotate, the rotating speed of the motor is measured through the encoder, and the mechanical torque output by the motor can be estimated by combining the calculated active power. Wherein:

the three-phase alternating voltage signal of the output end of the three-phase rectification-inversion system is reconstructed according to the switching state of the three-phase bridge arm according to the following formula:

wherein, T₁、T₂、T₃Respectively representing a period T_sInstantaneous phase voltage duty ratio given by three power tubes of the inner upper half bridge is given; v_dRepresenting the voltage on the dc bus; u shape_an、U_bn、U_cnThe reconstructed phase a, phase B and phase C voltages are shown.

The reconstruction of the three-phase alternating current signal of the output end of the three-phase rectification-inversion system according to the switching states of the three-phase bridge arms is obtained according to the corresponding relation between the direct current side current and the alternating current side current of the inverter under different switching states of the three-phase bridge arms of the inverter:

(1) when the bridge arm switch state is 100, the direct current bus current corresponds to + A phase current + i_a(ii) a When the bridge arm switch state is 101, the direct current bus current corresponds to the phase-B current (-i)_b) (ii) a When the bridge arm switch state is 001, the direct current bus current corresponds to + C phase current (+ i)_c) (ii) a When the bridge arm switch state is 011, the direct current bus current corresponds to the phase-A current (-i)_a) (ii) a When the bridge arm switch state is 010, the direct current bus current corresponds to + B phase current (+ i)_b) (ii) a When the bridge arm switch state is 110, the direct current bus current corresponds to the-C phase current (-i)_c) (ii) a When the bridge arm switch states are 000 and 111, the direct current bus current does not correspond to any phase current; as shown in table 1:

TABLE 1

Switch state (100) (101) (001) (011) (010) (110) (000) (111)

Corresponding phase current + i_a-i_b+i_c-i_a+i_b-i_c00

(2) First, any two-phase current is obtained according to i_a+i_b+i_cAnd obtaining a third phase current when the three-phase current is 0, namely reconstructing a three-phase alternating current signal.

The active power calculation of the three-phase inverter system is to calculate the active power P output to the motor according to the reconstructed three-phase alternating voltage signal and current signal and the phase difference between the two signals, and the formula is as follows:

wherein the content of the first and second substances,for reconstructing the three-phase voltage-current phase difference of the output terminal, I_nAnd U_nRespectively are a three-phase alternating current signal and a voltage signal which are reconstructed.

The calculating of the motor torque comprises the following steps:

(1) the calculation formula of the motor rotating speed N is obtained by the encoding number m of the encoder arranged on the motor shaft and the detection of the pulse number N output by the encoder per second as follows:

(2) according to the rotating speed n of the motor and the reconstructed active power P, the motor torque T is obtained by adopting the following formula:

fig. 2 is a hardware circuit structure diagram of a system according to an embodiment of the present invention, specifically, a 220V AC power supply is used for supplying power during an experiment, wherein a part of AC input is converted into AC-DC through a rectifier module, smooth DC is output, and then AC-DC conversion is realized through an inverter module to output three-phase AC for supplying power to a motor to drive a load to rotate. And the other part of the alternating current input passes through a switching power supply, and one part of the alternating current input respectively supplies power to the IPM module in the DSP and the inverter through an isolation power supply. And obtaining voltage and current signals of the direct current bus on the direct current bus through a direct current voltage and current sensor, transmitting the signals to the DSP through a feedback signal interface, and calculating in the DSP to obtain a reconstructed alternating current side voltage and current waveform. The speed of the motor is measured by using an encoder, and for six pairs of differential signals output by the encoder, the differential signals of the speed position are converted into single-ended signals through a differential receiver and input into the DSP. And converting the ABZ three-way differential signals into corresponding rotating speed signals through an internal orthogonal decoding module of the DSP. The active power can be obtained by calculating the three-phase voltage and current waveforms obtained by the DSP reconstruction, and then the motor rotating speed signals acquired by the DSP are combined to calculate by adopting a torque calculation model arranged in the DSP, so that the real-time torque of the motor is estimated. And the DSP displays the calculated data such as the motor torque and the like on a screen in real time through serial port communication. Meanwhile, the DSP generates PWM signals and sends the PWM signals to a driving circuit of an inverter power tube to realize closed-loop control of the motor.

The following model selection is taken as an example to illustrate the embodiment of the present invention, and when the embodiment of the present invention is implemented specifically, the embodiment of the present invention is not limited to this.

The method comprises the steps that an uncontrollable silicon rectifying module is used for a selected rectifying circuit, an FSBB30CH60 is selected for the inverter type selection, a CHB-25NP/SP9 closed-loop Hall current sensor is selected for a direct current sensor, an HV300GB Hall voltage sensor is selected for a direct current voltage sensor, a TMS320F28335 is selected for a DSP chip, the selected motor is a series alternating current servo motor 80CB075C-500000 of Sendai corporation, and the motor is provided with a photoelectric incremental encoder.

Obviously, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.