阅读说明：本技术 一种基于负载转矩动态补偿的压缩机控制方法 (Compressor control method based on load torque dynamic compensation ) 是由 赵文才 李鹏 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种基于负载转矩动态补偿的压缩机控制方法,包括如下步骤：(1)实时采集电机电流计算电磁转矩；(2)利用电磁转矩、负载转矩估算值以及电机机械常数估算电机转速；(3)利用电机转速估算值和电机转速实际值,推算负载转矩估计；(4)通过负载转矩估算值补偿压缩机转矩电流。本发明集成速度自适应估算和负载转矩估算,自动调谐扰动负载的频率成分,能准确估算负载转矩的波动,并实施对负载转矩的补偿,从而有效抑制压缩机系统的振动。本发明适用于无传感工作模式的压缩机转矩补偿,无需测试负载转矩变化特性曲线,在压缩机或者负载变化后仍能较好工作,其物理意义清晰易实现,具有一定的普适性和较高工程应用价值。(The invention discloses a compressor control method based on load torque dynamic compensation, which comprises the following steps: (1) collecting motor current in real time to calculate electromagnetic torque; (2) estimating the rotation speed of the motor by using the electromagnetic torque, the estimated value of the load torque and the mechanical constant of the motor; (3) estimating load torque estimation by using the estimated value and the actual value of the motor speed; (4) the compressor torque current is compensated by the load torque estimate. The invention integrates speed self-adaptive estimation and load torque estimation, automatically tunes the frequency component of disturbance load, can accurately estimate the fluctuation of the load torque, and implements compensation on the load torque, thereby effectively inhibiting the vibration of a compressor system. The method is suitable for the compressor torque compensation in a sensorless working mode, a load torque change characteristic curve does not need to be tested, the compressor can still work well after the compressor or the load changes, the physical significance of the method is clear and easy to realize, and the method has certain universality and higher engineering application value.)

1. A compressor control method based on load torque dynamic compensation is characterized by comprising the following steps:

(1) collecting the current of the motor in real time, and calculating the electromagnetic torque;

(2) estimating the motor speed by using the electromagnetic torque, the load torque estimated value and the motor mechanical constant to obtain a motor speed estimated value;

(3) calculating a load torque estimated value by using the motor rotating speed estimated value and the motor rotating speed actual value;

(4) and calculating a torque current compensation value based on the load torque estimation value to realize the compensation of the torque current of the compressor.

2. The method for controlling a compressor based on load torque dynamic compensation according to claim 1, wherein in the step (1), the electromagnetic torque is calculated as follows:

wherein Te is electromagnetic torque, λ_fThe rotor flux linkage is shown, id is an excitation current, iq is a torque current, Ld is a direct-axis inductor, and Lq is a quadrature-axis inductor.

3. The method for controlling a compressor based on load torque dynamic compensation according to claim 2, wherein the step (2) comprises the following steps:

constructing a relational expression of electromagnetic torque, estimated load torque, mechanical constant of the motor and estimated speed of the motor:

wherein Tl is the estimated value of load torque, J is the rotational inertia of the compressor system, B is the friction coefficient,is the estimated value of the motor speed;

obtaining the motor speed estimation value

Where s is a differential operator.

4. The compressor control method based on load torque dynamic compensation as claimed in claim 3, wherein in step (3), the estimated motor speed and the actual motor speed are input into a load torque estimation model, and a load torque estimated value is obtained by calculation;

the load torque estimation model comprises a first subtracter, a second subtracter, a third subtracter, a first proportional amplifier, a second proportional amplifier, a third proportional amplifier, a first multiplier, a second multiplier, a first integrator, a second integrator, a third integrator and a first adder;

the motor rotating speed estimated value is input into a forward input end of a first subtracter, and the motor rotating speed actual value is respectively input into a reverse input end of the first subtracter, a first input end of a first multiplier and a first input end of a second multiplier; the output end of the first subtracter is respectively connected with the input ends of the first proportional amplifier, the second proportional amplifier and the third integrator; the output end of the first proportional amplifier is connected with the first input end of the first adder; the output end of the third integrator is connected with the third input end of the first adder; the output end of the second proportional amplifier is connected with the positive input end of the second subtracter; the output end of the first integrator is respectively connected with the reverse input end of the second subtracter, the second input end of the second multiplier and the second input end of the first adder; the output end of the second subtracter is connected with the input end of a third proportional amplifier, and the output end of the third proportional amplifier is connected with the positive phase input end of the third subtracter; the output end of the second multiplier is connected with the input end of the second integrator, and the output end of the second integrator is connected with the reverse input end of the third subtracter; the output end of the third subtracter is connected with the second input end of the first multiplier, and the output end of the first multiplier is connected with the input end of the first integrator;

motor speed estimation valueSubtracting the actual value of the motor rotating speed by a first subtracter to obtain a first speed error value; the first speed error value is calculated by a first proportional amplifier to obtain a first proportional output; the first speed error value is calculated by a second proportional amplifier to obtain a second proportional output; subtracting the second proportional output and the first integral output by a second subtracter to obtain a second subtraction output; the second subtraction output is calculated by a third proportional amplifier to obtain a third proportional output; subtracting the third proportional output and the second integral output by a third subtracter to obtain a third subtraction output; multiplying the third subtraction output and the actual value of the motor rotating speed by a first multiplier to obtain a first multiplier output; the output of the first multiplier is accumulated through a first integrator to obtain the output of the first integrator; the output of the first integrator is multiplied by the actual value of the rotating speed of the motor through a second multiplier to obtain the output of the second multiplier; the output of the second multiplier is accumulated through a second integrator to obtain a second integral output; the first speed error value is calculated by a third integrator as a third integrated output; the first proportional output, the first integral output, and the third integral output are added by a first adder, and the sum is used as a load torque estimation value.

5. The compressor control method based on load torque dynamic compensation according to claim 4, wherein in the step (4), the torque current compensation value is calculated by the following method:

where Tl is the load torque estimate, i_{q_comp}Is a torque current compensation value.

Technical Field

The invention relates to a drive control of a compressor, in particular to a compressor control method based on load torque dynamic compensation.

Background

The permanent magnet synchronous motor has the characteristics of high power density, high operation efficiency, excellent control performance and the like, has high working efficiency, and is widely applied to the fields of household appliances, automobiles and the like. In air conditioning compressor applications, the load torque is typically fluctuating during one mechanical revolution. Real-time changes in load torque can cause fluctuations in compressor speed, such periodic mechanical jitter can significantly increase noise of the air conditioning compressor system, affect user experience, and continuous vibration of the system can also jeopardize equipment safety. Therefore, a torque compensation algorithm is highly desirable for this application to compensate for load torque to achieve reduced equipment vibration and noise.

The existing compensation scheme generally utilizes the characteristic of periodic variation of load torque, adopts a sine function to reconstruct the load torque, and in practical implementation, a group of compensation curves are usually built in, or the method is improved, and the optimal compensation effect is found by online adjusting the amplitude and the phase of the sine function. However, in practice, since the load torque does not change exactly sinusoidally, and if the load changes, the curve needs to be re-measured, the design effort is large, and finally, even if such a compensation scheme can improve the compressor vibration to some extent, the compensation accuracy and the vibration suppression effect are limited. In another compensation scheme, a load torque is estimated by a compressor system mechanical model in combination with a digital filter, but because the operating frequency of a compressor is dynamically changed and the mechanical jitter also contains abundant harmonic vibration frequencies, the difficulty of frequency processing of the digital filter is increased, the filter coefficient is very sensitive, the system can be stabilized by repeatedly trial and error of the relation number in practical application, and the universality and the robustness are lacked.

Therefore, there is a need to solve the above problems.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides a compressor control method based on load torque dynamic compensation, which can realize accurate compensation on alternating load torque, thereby obviously improving the vibration phenomenon of a system.

The technical scheme is as follows: in order to achieve the above object, the present invention discloses a compressor control method based on load torque dynamic compensation, comprising the following steps:

(1) collecting the current of the motor in real time, and calculating the electromagnetic torque;

(2) estimating the motor speed by using the electromagnetic torque, the load torque estimated value and the motor mechanical constant to obtain a motor speed estimated value;

(3) calculating a load torque estimated value by using the motor rotating speed estimated value and the motor rotating speed actual value;

(4) and calculating a torque current compensation value based on the load torque estimation value to realize the compensation of the torque current of the compressor.

Further, in step (1), the electromagnetic torque is calculated as follows:

wherein Te is electromagnetic torque, λ_fThe rotor flux linkage is shown, id is an excitation current, iq is a torque current, Ld is a direct-axis inductor, and Lq is a quadrature-axis inductor.

Further, the step (2) comprises the following steps:

constructing a relational expression of electromagnetic torque, estimated load torque, mechanical constant of the motor and estimated speed of the motor:

wherein Tl is the estimated value of load torque, J is the rotational inertia of the compressor system, B is the friction coefficient,is the estimated value of the motor speed;

obtaining the motor speed estimation value

Where s is a differential operator.

Further, in the step (3), inputting the estimated value of the motor speed and the actual value of the motor speed into a load torque estimation model, and calculating to obtain an estimated value of the load torque;

the load torque estimation model comprises a first subtracter, a second subtracter, a third subtracter, a first proportional amplifier, a second proportional amplifier, a third proportional amplifier, a first multiplier, a second multiplier, a first integrator, a second integrator, a third integrator and a first adder;

the motor rotating speed estimated value is input into a forward input end of a first subtracter, and the motor rotating speed actual value is respectively input into a reverse input end of the first subtracter, a first input end of a first multiplier and a first input end of a second multiplier; the output end of the first subtracter is respectively connected with the input ends of the first proportional amplifier, the second proportional amplifier and the third integrator; the output end of the first proportional amplifier is connected with the first input end of the first adder; the output end of the third integrator is connected with the third input end of the first adder; the output end of the second proportional amplifier is connected with the positive input end of the second subtracter; the output end of the first integrator is respectively connected with the reverse input end of the second subtracter, the second input end of the second multiplier and the second input end of the first adder; the output end of the second subtracter is connected with the input end of a third proportional amplifier, and the output end of the third proportional amplifier is connected with the positive phase input end of the third subtracter; the output end of the second multiplier is connected with the input end of the second integrator, and the output end of the second integrator is connected with the reverse input end of the third subtracter; the output end of the third subtracter is connected with the second input end of the first multiplier, and the output end of the first multiplier is connected with the input end of the first integrator.

Motor speed estimation valueSubtracting the actual value of the motor rotating speed by a first subtracter to obtain a first speed error value; the first speed error value is calculated by a first proportional amplifier to obtain a first proportional output; the first speed error value is calculated by a second proportional amplifier to obtain a second proportional output; subtracting the second proportional output and the first integral output by a second subtracter to obtain a second subtraction output; the second subtraction output is calculated by a third proportional amplifier to obtain a third proportional output; subtracting the third proportional output and the second integral output by a third subtracter to obtain a third subtraction output; multiplying the third subtraction output and the actual value of the motor rotating speed by a first multiplier to obtain a first multiplier output; the output of the first multiplier is accumulated through a first integrator to obtain the output of the first integrator; the output of the first integrator is multiplied by the actual value of the rotating speed of the motor through a second multiplier to obtain the output of the second multiplier; the output of the second multiplier is accumulated through a second integrator to obtain a second integral output; the first speed error value is calculated by a third integrator as a third integrated output; the first proportional output, the first integral output, and the third integral output are added by a first adder, and the sum is used as a load torque estimation value.

Further, in step (4), the torque current compensation value is calculated by the following method:

where Tl is the load torque estimate, i_{q_comp}Is a torque current compensation value.

In compressor applications, fluctuations in compressor speed can be induced due to real-time changes in load torque, thereby exacerbating compressor and associated piping vibrations, which can not only increase noise but can also compromise equipment safety.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages:

1. the method integrates speed self-adaptive estimation and load torque estimation, automatically tunes the frequency component of the disturbance load, realizes accurate estimation of the alternating load torque of the compressor, and implements compensation of the load torque, thereby effectively inhibiting the vibration of the compressor system;

2. the method is suitable for the compressor torque compensation in a sensorless working mode, a load torque change characteristic curve does not need to be tested, the compressor can still work well after the compressor or the load changes, the physical significance of the method is clear and easy to realize, and the method has certain universality and higher engineering application value.

Drawings

FIG. 1 is a control schematic of the present invention;

FIG. 2 is a schematic of an electromagnetic torque calculation;

FIG. 3 is a schematic diagram of motor speed estimation;

fig. 4 is a view showing a structure of a load torque estimation model.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

As shown in fig. 1 to 4, the present invention relates to a compressor control method based on load torque dynamic compensation, which comprises the following steps:

step one, collecting the current of a motor in real time and calculating the electromagnetic torque.

The electromagnetic torque is calculated by:

wherein Te is electromagnetic torque, λ_fThe rotor flux linkage is shown, id is an excitation current, iq is a torque current, Ld is a direct-axis inductor, and Lq is a quadrature-axis inductor.

The conventional sensorless vector control needs to acquire motor phase currents ia, ib and ic and observe a rotor magnetic field angle theta and a rotor magnetic field speed omega, and the calculation method of the excitation current id and the torque current iq comprises the following steps:

and step two, estimating the motor speed by using the electromagnetic torque, the load torque estimated value and the motor mechanical constant to obtain the motor speed estimated value.

Firstly, the electromagnetic torque, the estimated load torque, the mechanical constant of the motor and the estimated motor speed have the following relations:

wherein Tl is the estimated value of load torque, J is the rotational inertia of the compressor system, B is the friction coefficient,is an estimate of the motor speed.

Calculating the estimated value of the motor speed according to the relation:

where s is a differential operator.

And thirdly, calculating a load torque estimated value by using the motor rotating speed estimated value and the motor rotating speed actual value.

Specifically, a load torque estimation model is constructed, an estimated value of the motor speed and an actual value of the motor speed are input into the load torque estimation model, and an estimated value of the load torque is calculated.

The load torque estimation model comprises a first subtracter, a second subtracter, a third subtracter, a first proportional amplifier, a second proportional amplifier, a third proportional amplifier, a first multiplier, a second multiplier, a first integrator, a second integrator, a third integrator and a first adder.

The motor rotating speed estimated value is input into a positive input end of the first subtracter, and the motor rotating speed actual value is respectively input into a negative input end of the first subtracter, a first input end of the first multiplier and a first input end of the second multiplier.

The output end of the first subtracter is respectively connected with the input ends of the first proportional amplifier, the second proportional amplifier and the third integrator.

The output end of the first proportional amplifier is connected with the first input end of the first adder. The output end of the third integrator is connected with the third input end of the first adder.

The output end of the second proportional amplifier is connected with the positive input end of the second subtracter; the output end of the first integrator is respectively connected with the inverting input end of the second subtracter, the second input end of the second multiplier and the second input end of the first adder.

The output end of the second subtracter is connected with the input end of a third proportional amplifier, and the output end of the third proportional amplifier is connected with the positive phase input end of the third subtracter; the output end of the second multiplier is connected with the input end of the second integrator, and the output end of the second integrator is connected with the inverted input end of the third subtracter.

The output end of the third subtracter is connected with the second input end of the first multiplier, and the output end of the first multiplier is connected with the input end of the first integrator.

Calculating a first speed error value by the motor rotating speed estimated value and the motor rotating speed actual value through a first subtracter; calculating a first proportional output by the first speed error value through a first proportional amplifier; the first speed error value is used for calculating a second proportional output through a second proportional amplifier; the second proportional output and the first integral output are subtracted by a second subtracter to obtain a second subtraction output; the second subtraction output is used for obtaining a third proportional output through a third proportional amplifier; subtracting the third proportional output and the second integral output by a third subtracter to obtain a third subtraction output; multiplying the third subtraction output and the actual value of the motor rotating speed by a first multiplier to obtain the output of the first multiplier; the output of the first multiplier is accumulated by a first integrator to obtain the output of the first integrator; multiplying the output of the first integrator and the actual value of the motor rotating speed through a second multiplier to obtain the output of the second multiplier; the output of the second multiplier is accumulated through a second integrator to obtain a second integral output; the first speed error value is calculated by a third integrator as a third integrated output; the first proportional output, the first integral output, and the third integral output are added by a first adder, and the sum is used as a load torque estimation value.

And step four, calculating a torque current compensation value based on the load torque estimated value to realize the compensation of the torque current of the compressor.

The conventional sensorless control technology for compressors generally adopts vector control, and the reference value of the torque current is given by a speed regulator, the fluctuation of the motor speed can be caused by the fluctuation of the load of the compressor, and the fluctuation of the reference value of the torque current is brought, and the loop coupling can be eliminated by introducing the load torque.

The torque current compensation value of the invention is calculated by the load torque estimated value and is superposed on the torque current reference value and the torque electricity

The flow compensation value is calculated as follows:

where Tl is the load torque, i_{q_comp}Is a torque current compensation value.