A compensation system for electric power closed-loop loading control

Abstract

The present invention discloses a compensation system for electric closed-loop loading control, including a closed-loop loading controller input compensation module and a closed-loop loading controller output compensation module. The closed-loop loading controller input compensation module samples the load torque analog voltage value, and at the same time, combines the load torque sampling hysteresis ratio constraint condition and the closed-loop loading controller input compensation limit function to calculate the closed-loop loading controller input compensation amount, thereby realizing compensation for the closed-loop loading controller input amount. The closed-loop loading controller output compensation module samples the load torque given value, and at the same time, according to the load torque given value differential ratio constraint condition and the closed-loop loading controller output compensation limit function, gives the closed-loop loading controller output compensation amount, thereby realizing compensation for the closed-loop loading controller output amount. The present invention can effectively reduce the load torque sampling error, and at the same time, can significantly improve the system's following performance under complex given signals.

Description

Technical Field

[0001] The invention belongs to the field of motor control, and in particular relates to a compensation system for electric power closed-loop loading control. Background Art

[0002] A loader (dynamometer) is a device that provides torque to the motor power system and can be used to test the performance of the motor under load. In products powered by motors, such as CNC machine tools, washing machines, and electric vehicles, the internal motors will be subjected to various types of loads during actual use; during factory inspection, a loader can be used to simulate actual loads to perform load tests on them, and decisions such as whether to allow the product to leave the factory or continue to improve it can be made based on the specific performance.

[0003] The following are several traditional and widely used loaders.

[0004] (1) Eddy current loader

[0005] The eddy current loader generates eddy currents through the movement of the induction disk, which then generates a magnetic field and interacts with the air gap magnetic field to generate torque to achieve the purpose of loading. The eddy current loader has the advantages of simple structure, easy operation, high test accuracy, good stability, and long service life. However, the internal structure of the loader is relatively complex and difficult to maintain.

[0006] (2) Magnetic Powder Loader

[0007] The magnetic powder loader is based on the electromagnetic principle and uses magnetic powder to transmit torque. Its braking torque is basically proportional to the excitation current. By adjusting the excitation current, stepless control can be achieved. This loader has a simple structure, is easy to use, and has high accuracy. However, it is not suitable for long-term operation to avoid sintering of magnetic powder due to high temperature generated by heat, which reduces the service life. Water should be used for forced cooling during operation. This loading method is very suitable for testing the torque of medium and small motors.

[0008] (3) Hysteresis Loader

[0009] The hysteresis loader is a device that repeatedly magnetizes the pulsating magnetic field when the hysteresis rotor cup rotates in the air gap, thereby generating hysteresis loss and forming a resistance torque in the opposite direction of the rotor rotation, that is, a braking torque, to achieve the purpose of loading. The hysteresis loader has a simple structure, a small rotor inertia, no friction loss of brush slip rings or commutators, good high-speed performance, and stable testing. However, when the power of the loader is high, the auxiliary equipment is more complicated and the accuracy is lower.

[0010] In recent years, with the increasingly sophisticated workmanship of motors and the increasing maturity of motor control theory, electric loaders based on motors have gradually become popular. This loader has the advantages of low heat generation, easy operation, easy use, and low operating costs. Most importantly, the loading characteristics of this loader are very good, and it can load almost from scratch. Whether it is high speed or low speed (extremely low speed or even zero speed), it can load stably, and its loading stability is unmatched by any previous loading equipment.

[0011] As a kind of electric loader, surface-mounted permanent magnet synchronous motor (SPMSM) has the advantages of simple structure, high power density, high torque-to-inertia ratio, good dynamic performance, etc., and with the reduction in the price of permanent magnet materials such as rare earth and ferrite and the improvement in performance, its application in loading systems is becoming more and more extensive.

[0012] Figure 1 This is a block diagram of a traditional power closed-loop load control system based on SPMSM, which is widely used. The inverter is in torque control mode and uses vector control. PI T The control objective of the closed-loop PI controller is to make the load torque value T L Following load torque value given value PI T The input is E L , the output is That is, the electromagnetic torque simulation voltage value T eA The given value of . The output is given to the frequency converter, and after a series of operations such as coordinate transformation, PI adjustment, and SVPWM, the drive signal is output to the inverter, thereby controlling the loading of the SPMSM.

[0013] However, in actual situations, the load waveforms of the motors under test vary. For example, when the waveform is a high-frequency sine wave or a triangular wave, the following performance of the above control system will be greatly reduced, which is not suitable for military, aerospace and other occasions that require high loading accuracy. Summary of the invention

[0014] In view of the above technical defects in the prior art, the present invention provides a compensatory system for electrical closed-loop loading control (CSECLLC). The method can effectively improve the following performance of the traditional electrical closed-loop loading control system under complex given signals.

[0015] The compensation system (CSECLLC) for electric power closed-loop loading control proposed in the present invention comprises: a closed-loop loading controller input compensation module (CMICLLC) and a closed-loop loading controller output compensation module (CMOCLLC).

[0016] The closed-loop loading controller inputs a compensation module to simulate the load torque voltage value T LA Sampling is performed, and the initial value COM of the input compensation of the closed-loop load controller is calculated by combining the load torque zero-lag ratio μ0, load torque first-order lag ratio μ1, load torque second-order lag ratio μ2, and load torque third-order lag ratio μ3 given by the load torque sampling lag ratio constraint condition. I ; Based on the closed-loop load controller input compensation limit function LIM I (.), combined with the rated torque T of the loading motor NL , Rated torque of the motor under test T NT , the ratio of load torque simulation voltage value to actual valueΞ L , input the initial value of compensation COM to the closed-loop loading controller I Limiting is performed to obtain the input compensation of the closed-loop loading controller Realize the closed-loop loading controller input E L compensation;

[0017] The closed-loop loading controller outputs a compensation module to a given value of the load torque Sampling is performed, and the load torque given value ratio η and the load torque given value first-order differential ratio λ are given based on the load torque given value differential ratio constraint condition, and at the same time, the closed-loop load controller sampling period t PIT , calculate the initial value COM of the closed-loop loading controller output compensation O ; Based on the closed-loop load controller output compensation limit function LIM O (.), combined with the rated torque T of the loading motor NL , Rated torque of the motor under test T NT , the ratio of the electromagnetic torque simulation voltage value to the actual valueΞ e , for COM O Limiting is performed to obtain the output compensation of the closed-loop loading controller Realize the output of the closed-loop loading controller, that is, the electromagnetic torque analog voltage value T eA The given value compensation.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The closed-loop loading controller input compensation module (CMICLLC) in the present invention can effectively reduce the load torque sampling error and improve the stability of system operation.

[0020] (2) The closed-loop loading controller output compensation module (CMOCLLC) in the present invention can effectively improve the following performance of the system under complex given signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the block diagram of the traditional power closed-loop loading control system based on SPMSM;

[0022] Figure 2 It is a block diagram of the CSECLLC system of the present invention;

[0023] Figure 3 Load torque waveform when square wave load is applied to the motor (cycle is 2s);

[0024] Figure 4 Load torque waveform when a square wave load is applied to the motor (cycle is 1s);

[0025] Figure 5 Load torque waveform when a sinusoidal load is applied to the motor (period is 2s);

[0026] Figure 6 Load torque waveform when a sinusoidal load is applied to the motor (period is 1s);

[0027] Figure 7 Load torque waveform when a triangular wave load is applied to the motor (cycle is 2s);

[0028] Figure 8 Load torque waveform when a triangular wave load is applied to the motor (period is 1s). DETAILED DESCRIPTION

[0029] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0030] like Figure 2 As shown, the CSECLLC system of the present invention includes a closed-loop loading controller input compensation module (CMICLLC) and a closed-loop loading controller output compensation module (CMOCLLC).

[0031] Among them, the closed-loop loading controller input compensation module simulates the voltage value T of the load torque LA Sampling is performed, and the initial value COM of the input compensation of the closed-loop load controller is calculated by combining the load torque zero-lag ratio μ0, load torque first-order lag ratio μ1, load torque second-order lag ratio μ2, and load torque third-order lag ratio μ3 given by the load torque sampling lag ratio constraint condition. I; Based on the closed-loop load controller input compensation limit function LIM I (.), combined with the rated torque T of the loading motor NL , Rated torque of the motor under test T NT , the ratio of load torque simulation voltage value to actual valueΞ L , input the initial value of compensation COM to the closed-loop loading controller I Limiting is performed to obtain the input compensation of the closed-loop loading controller Realize the closed-loop loading controller input E L compensation;

[0032] Specifically, the purpose of CMICLLC is to better reduce the sampling error. In CMICLLC, firstly, T LA Sampling is performed, and the initial value COM of the input compensation of the closed-loop loading controller can be calculated by combining μ0, μ1, μ2, and μ3. I for

[0033] COM I =(μ0-1)T LA (k)+μ1T LA (k-1)+μ2T LA (k-2)+μ3T LA (k-3)

[0034] Among them, T LA (k) is T LA The current sample value, T LA (k-1) is T LA The first-order lag sampling value, T LA (k-2) is T LA The second-order lag sampling value, T LA (k-3) is T LA The values ​​of μ0, μ1, μ2, and μ3 should satisfy the following load torque sampling lag ratio constraint conditions:

[0035]

[0036] Input compensation limiting function LIM based on closed-loop load controller I (.), combined with T NL 、T NT ,Ξ L , for COM I Limit the amplitude to obtain the input compensation of the closed-loop loading controller

[0037]

[0038] The main purpose of CMOCLLC is to improve the system's follow-up performance for complex given signals. Sampling is performed while combining η, λ, and t PIT The initial value of the closed-loop load controller output compensation COM can be calculated O for

[0039]

[0040] in, for The current sample value of for The first-order lag sampling value of . The values ​​of η and λ should satisfy the following load torque given value differential weight constraint conditions

[0041]

[0042] Output compensation limiting function LIM based on closed-loop load controller O (.), combined with T NL , T NT ,Ξ e , for COM O Limit the amplitude to obtain the output compensation of the closed-loop loading controller

[0043]

[0044] Finally, the system block diagram of CSECLLC is as follows Figure 2 As shown. L | com For E L The value after compensation, for When the system is working, CMICLLC has a positive effect on T LA Sampling is performed, and the initial value COM of the input compensation of the closed-loop load controller is calculated by combining μ0, μ1, μ2, and μ3 given by the load torque sampling hysteresis ratio constraint condition. I ; Based on the closed-loop load controller input compensation limit function LIM I (.), combined with T NL , T NT ,Ξ L , for COM I Limiting is performed to obtain the input compensation of the closed-loop loading controller Realize the closed-loop loading controller input E L Compensation of CMOCLLC Sampling is performed, and η and λ are given based on the differential weight constraint of the load torque given value, and t PIT, calculate the initial value COM of the closed-loop loading controller output compensation O ; Based on the closed-loop load controller output compensation limit function LIM O (.), combined with T NL 、T NT ,Ξ e , for COM O Limiting is performed to obtain the output compensation of the closed-loop loading controller Realize the output of the closed-loop loading controller, that is, the electromagnetic torque analog voltage value T eA The given value compensation.

[0045] The present invention further builds an electric closed-loop loading control experimental platform, and the main control module adopts a Speedgoat controller. The parameters of the loading motor and the measured motor are shown in Table 1 and Table 2 respectively.

[0046] Table 1 Loading SPMSM parameters

[0047]

[0048]

[0049] Table 2 Parameters of the tested SPMSM

[0050] parameter Numeric <![CDATA[Rated voltage U N > 92V <![CDATA[Rated current I N > 1.7A <![CDATA[Rated power P N > 200W <![CDATA[Rated speed n N > 3000rpm <![CDATA[Rated torque T NT > 640N·mm Moment of inertia J <![CDATA[1.61×10 -5 kg·m 2 ]]> <![CDATA[Stator resistance R s > 4.20Ω <![CDATA[Stator inductance L s > 6.99mH <![CDATA[Permanent magnet flux linkage ψ f > 0.0412Wb Pole pair number p 5

[0051] Here, when the loading waveform is a square wave, a sine wave, and a triangle wave with a period of 2s and 1s, the waveforms of the load torque reference and actual value under the two closed-loop algorithms without and with CSECLC are given respectively. Figure 3-8 It can be seen that after adding the CSECLLC of the present invention, the dynamic response speed and control accuracy of the load torque are significantly improved.

[0052] Table 3 gives the specific values ​​of the two following performance indicators, the phase shift rate and the control error of the load torque under the control of the two closed-loop algorithms without and with CSECLC. At the square wave period of 2s and 1s, after adding the CSECLLC of the present invention, the phase shift rate generated is reduced by 88.8% and 89.7%, respectively, and the control error is reduced by 62.5% and 68.6%, respectively; at the sine wave period of 2s and 1s, after adding CSECLLC, the phase shift rate generated is reduced by 77.8% and 83.7%, respectively, and the control error is reduced by 72.9% and 76.9%, respectively; at the triangle wave period of 2s and 1s, after adding CSECLLC, the phase shift rate generated is reduced by 81.8% and 86.4%, respectively, and the control error is reduced by 70.7% and 74.1%, respectively. After adding CSECLLC, the following performance is greatly improved.

[0053] Table 3 Load torque following performance index values ​​when CSECLLC is not added and added

[0054]

[0055] Note:

[0056] It can be seen that the compensation system for electric closed-loop loading control proposed in the present invention can effectively reduce the load torque sampling error and significantly improve the following performance of the system under complex given signals.

[0057] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A compensation system for electric closed-loop loading control, characterized in that: It includes a closed-loop loading controller input compensation module and a closed-loop loading controller output compensation module; The closed-loop loading controller inputs a compensation module to simulate the load torque voltage value T LA Sampling, load torque analog voltage value T LA As the input quantity E of the closed-loop load controller L At the same time, combined with the load torque zero lag ratio μ0, load torque first-order lag ratio μ1, load torque second-order lag ratio μ2, load torque third-order lag ratio μ3 given by the load torque sampling lag ratio constraint condition, the initial value COM of the closed-loop load controller input compensation is calculated I ; Based on the closed-loop load controller input compensation limit function LIM I (.), combined with the rated torque T of the loading motor NL , Rated torque of the motor under test T NT , the ratio of load torque simulation voltage value to actual valueΞ L , input the initial value of compensation COM to the closed-loop loading controller I Limiting is performed to obtain the input compensation of the closed-loop loading controller Realize the closed-loop loading controller input E L compensation; The closed-loop loading controller outputs a compensation module to a given value of the load torque Sampling is performed, and the load torque given value ratio η and the load torque given value first-order differential ratio λ are given based on the load torque given value differential ratio constraint condition, and at the same time, the closed-loop load controller sampling period t PIT , calculate the initial value COM of the closed-loop loading controller output compensation O ; Based on the closed-loop load controller output compensation limit function LIM O (.), combined with the rated torque T of the loading motor NL , Rated torque of the motor under test T NT , the ratio of the electromagnetic torque simulation voltage value to the actual valueΞ e , for COM O Limiting is performed to obtain the output compensation of the closed-loop loading controller Realize the output of the closed-loop loading controller, that is, the electromagnetic torque analog voltage value T eA The given value compensation.

2. The compensation system for power closed-loop loading control according to claim 1, characterized in that: In the closed-loop loading controller input compensation module, the closed-loop loading controller input compensation amount initial value COM I The calculation formula is: COM I =(μ0-1)T LA (k)+μ1T LA (k-1)+μ2T LA (k-2)+μ3T LA (k-3) Among them, T LA (k) is T LA The current sample value, T LA (k-1) is T LA The first-order lag sampling value, T LA (k-2) is T LA The second-order lag sampling value, T LA (k-3) is T LA The third-order lag sampling value of The values ​​of μ0, μ1, μ2, and μ3 should satisfy the following load torque sampling hysteresis ratio constraint conditions:

3. The compensation system for power closed-loop loading control according to claim 1, characterized in that: The COM I Limit the amplitude to obtain the input compensation of the closed-loop loading controller The formula is:

4. The compensation system for electric closed-loop loading control according to claim 1, characterized in that: In the closed-loop loading controller output compensation module, the closed-loop loading controller outputs the initial value of the compensation amount COM O The calculation formula is as follows: in, for The current sample value of for The first-order lag sampling value of ; the values ​​of η and λ should satisfy the following load torque given value differential weight constraint conditions 5. The compensation system for electric power closed-loop loading control according to claim 1, characterized in that: About COM O Limiting is performed to obtain the output compensation of the closed-loop loading controller The formula is:

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