CN-117526787-B - Power factor optimal control method based on large inertia asynchronous motor vector control

CN117526787BCN 117526787 BCN117526787 BCN 117526787BCN-117526787-B

Abstract

The invention belongs to the technical field of variable frequency speed regulation of asynchronous motors, and particularly relates to a power factor optimal control method based on vector control of a large inertia asynchronous motor, which comprises the steps of firstly calculating a rotor Flux linkage given initial value Flux 0 , secondly determining a corresponding slip angular speed w sy when the optimal power factor runs, inputting the rotor Flux linkage given initial value Flux 0 in the first step, thirdly reading a real-time rotating speed difference e value, fourthly judging overspeed of the motor, fifthly, reading real-time torque current Is q when the overspeed value-e of the fourth motor reaches a set value A, performing the sixth step, directly performing the seventh step of calculating the rotor Flux linkage given value Flux set ＝Flux 0 when the overspeed value-e of the fourth motor does not reach the set value A, and seventhly, calculating and outputting an excitation current fixed value Isd set .

Inventors

HE JINCHENG
GAO DINGQIANG
HU HAOTIAN
KANG LI
DENG MAOCAI
ZHANG JIAN
LI HUAJUN
WANG HAIBING
PENG JIANFEI
WANG YINGQIAO
XUAN WEIMIN
CHEN YONG
WANG XIAOPING
RAN WENJIE

Assignees

核工业西南物理研究院

Dates

Publication Date: 20260512
Application Date: 20220728

Claims (6)

1. The power factor optimal control method based on the large inertia asynchronous motor vector control is characterized by comprising the following steps of: before inputting a power factor optimal control method algorithm based on large inertia asynchronous motor vector control, comprehensively considering starting torque, stator voltage, stator current, power factor and field debugging experience calculation of a unit to obtain a rotor Flux linkage given initial value Flux 0 Step two, determining the corresponding slip angular speed when the optimal power factor operates Inputting the target slip angular velocity value when the optimal power factor is running Inputting the rotor Flux linkage given initial value Flux 0 obtained in the first step; Step three, reading a real-time rotating speed difference e value; Judging the overspeed of the motor, namely judging whether the overspeed value e of the motor reaches the input speed condition of the input speed condition set value A of the power factor optimal control method algorithm when the real-time rotating speed difference e read in the step three is the overspeed value-e of the motor; step five, when the overspeed value-e of the motor in the step four reaches the set value A, reading the real-time torque current Is q , and carrying out the step six; When step four motor overspeed value-e does not reach set value a, rotor Flux linkage set value Flux set = Flux 0 goes directly to step seven; Step six, calculating a rotor Flux linkage given value Flux set ; Step seven, calculating and outputting the excitation current fixed value Isd set; The second step comprises running slip angular speed when different motors run Having a single operating power factor And power factor Angular velocity with running slip The increase of (1) shows a trend of increasing and then decreasing; thus, by the optimum power factor And determining corresponding slip angular speed when the optimal power factor operates by limiting the voltage and current of the motor stator in the speed regulation process ; The step six of calculating the rotor Flux linkage given value Flux set includes: by the following formula (1): Flux set =Lm*Is q /(Tr*Wsy)...........................(1) Calculating a rotor Flux linkage given value Flux set , wherein Lm Is motor mutual inductance, tr Is asynchronous motor rotor time constant, and Is q Is torque current; the seventh step comprises the step of calculating the rotor Flux linkage given value Flux set By the following formula (2): Isd set =Flux set /Lm..............................(2) Calculating a real-time given value of exciting current, outputting the real-time given value to a vector control main program, and executing a current and rotating speed double-closed-loop vector control algorithm, wherein Isd set is the real-time given value of exciting current and is input after the speed reaches a set value, isd set0 is an initial given value of exciting current and is a fixed value before the speed does not reach the set value.
2. The method for optimally controlling the power factor based on the vector control of the large inertia asynchronous motor according to claim 1, wherein the third step comprises the steps of real-time rotating speed difference e=F set -F run ; When the rotating speed of the motor does not reach the set rotating speed stage, the e value is larger than zero; when the motor rotation speed exceeds the set rotation speed stage, the e value is smaller than zero, namely the motor overspeed value-e; Wherein, F run is the real-time rotating speed and position feedback value of the motor obtained by the DSP main control board through the photoelectric code disc, F set is the target speed given value in the vector control speed loop.
3. The method for controlling the optimal power factor based on the vector control of the large inertia asynchronous motor according to claim 2, wherein in the fourth step, whether the overspeed value-e of the motor reaches the input speed condition set value A of the optimal power factor control method algorithm input speed condition set value A comprises the steps that 0< = A < e 0 , the stator has the debugging effect of stable current and smooth transition, and e 0 is the speed overshoot.
4. The method for optimally controlling the power factor based on the vector control of the large-inertia asynchronous motor according to claim 3, wherein the real-time torque current Is q in the step five Is obtained by 3s/2r of three-phase stator current acquired and calculated by a current sensor in a vector control main program, and the real-time torque current Is q indirectly reflects the real-time output electromagnetic torque of the asynchronous motor.
5. The optimal control method of the power factor based on the vector control of the large inertia asynchronous motor according to claim 1, wherein the second step further comprises: <= <= ; , wherein, 、 To determine the minimum and maximum values of the ideal operating power factor of the parametric asynchronous motor, 、 The minimum value and the maximum value of the ideal slip angular speed of the parameter asynchronous motor are determined.
6. The method for controlling optimal power factor based on vector control of large inertia asynchronous motor according to claim 1, wherein the step five further comprises calculating the excitation current given value according to the real-time output torque of the motor to ensure that the slip angular speed of the motor is maintained at the ideal slip angular speed In the vicinity of the torque parameter, the torque parameter is not present in the vector control process quantity, and thus the stator current torque component is converted.

Description

Power factor optimal control method based on large inertia asynchronous motor vector control Technical Field The invention belongs to the technical field of variable frequency speed regulation of asynchronous motors, and particularly relates to a power factor optimal control method based on vector control of a large-inertia asynchronous motor. Background In the short-time and high-power electricity utilization field (such as fusion research, electromagnetic ejection and the like), in order to reduce the investment of power transformation and distribution facilities and the impact on a power grid in the electricity utilization process, a mature and reliable power supply scheme is generally adopted to provide electric energy for electric equipment by utilizing a high-power pulse generator set. The pulse generator set is formed by coaxially connecting a dragging motor, a flywheel and a synchronous generator, and realizes the conversion and transmission of electric energy by utilizing a mechanical energy storage and pulse discharge mode. The scheme is characterized in that the accumulation (acceleration period) and storage (waiting discharge period) time (T1) of the electric energy are far longer than the discharge time (T2). For a high-power pulse generator set, the high-power pulse generator set has super-large shafting moment of inertia or super-high rotating speed, high requirements are put on the speed regulation performance of the set, a large amount of electric energy is required to be consumed during T1 to achieve acceleration and speed stabilization of the set, and how to efficiently utilize the electric energy and reduce energy loss in the electric energy conversion process is important to the energy-saving effect of the power supply system. The energy consumption mainly comprises mechanical loss and electrical loss, the former is mainly related to the hardware construction process of the equipment and the inherent mechanical property of the equipment, and the latter is mainly related to the control algorithm in the speed regulation process and the electrical property of part of hardware equipment. The invention mainly aims at optimizing a speed control algorithm of a high-power pulse generator set to improve the running power factor of the dragging motor, thereby reducing unnecessary energy consumption caused by excessive reactive power transmission, and achieving the purposes of improving the capacity utilization rate of speed regulating equipment, reducing the electric energy loss and prolonging the service life of the equipment (a frequency converter and the dragging motor). The existing mainstream high-power variable-frequency speed regulation mainly comprises VVF control, vector control and direct torque control. The VVF control is simple to realize, but has poor control performance, is mainly suitable for the field with low speed regulation requirement, has excellent speed regulation performance in direct torque control, but has insufficient maturity in low-speed section speed regulation performance to be further improved, and vector control has excellent speed regulation performance, although the implementation depends on motor parameters, along with the dynamic identification of the parameters and the mature application of various compensation means, the speed regulation performance can meet the requirement of most high-performance speed regulation fields (including pulse unit speed regulation) at present. However, in the traditional vector control, the output power factor of the frequency converter is greatly influenced by the load of the motor, and a proper exciting current set value is generally selected to realize a relatively high running power factor of a certain rotating speed section, so that the whole-process high-power factor running is difficult to realize for a high-power speed regulating system with variable load and variable working rotating speed. Disclosure of Invention The invention provides a power factor optimal control method based on vector control of a large inertia asynchronous motor, which is used for solving the technical problem that the electromagnetic torque output by the asynchronous motor in real time cannot be dynamically tracked in the prior art, and the optimal exciting current real-time given value is calculated. The technical scheme of the invention is as follows: The power factor optimal control method based on the vector control of the large inertia asynchronous motor comprises the following steps: before inputting a power factor optimal control method algorithm based on large inertia asynchronous motor vector control, comprehensively considering starting torque, stator voltage, stator current, power factor and field debugging experience calculation of a unit to obtain a rotor Flux linkage given initial value Flux 0 Step two, determining a corresponding slip angular speed w sy when the optimal power factor operates, inputting a target slip angular speed va