Method for controlling only PID of lift force single closed loop of bearing free motor

Abstract

The invention discloses a method for controlling an only PID of a lift force single closed loop of a bearing free motor, which comprises the following steps: obtaining the size and the direction of rotor eccentric displacement through polar coordinate transformation of rotor offsets in the X and Y directions; obtaining a given amplitude value of a lift force required by control through the regulating action of a PID; changing the expression form of a lift force polar coordinate at that time to obtain the lift forces under an X coordinate and a Y coordinate; calculating the magnetic linkage value for an suspension winding at the next moment by a lift force mathematical model brought into the magnetic linkage expression by a torque air gap magnetic linkage which is transferred by a torque winding control system; substracting the magnetic linkage value with a fed back suspension winding magnetic linkage value to obtain a magnetic linkage value required to be increased, and inputting the vector difference thereof into an SVPWM directly; and obtaining a switching signal of an inverter through a basic space voltage vector algorithm to compose the required suspension winding magnetic linkage which acts together with the torque air gap magnetic linkage to obtain the lift force required by the next moment so as to achieve quick and accurate control of the lift force and the stable suspension of the motor.

Description

technical field [0001] The invention relates to a control method of a bearingless motor, in particular to a single closed-loop unique PID control method for the suspension force of the bearingless motor. Background technique [0002] The control of a bearingless motor is usually divided into two parts: torque control and levitation force control. [0003] ① At present, domestic and foreign scholars' research on the control of bearingless motors is focused on how to realize the decoupling of the torque winding and the suspension winding. On the basis of field-oriented vector control, the levitation effect not only depends on the accuracy of the field-oriented control of the torque winding, but also is constrained by the accuracy of the field-oriented control of the levitation winding itself. [0004] ②The traditional levitation winding control is to control the levitation winding magnetic field by controlling the levitation winding current, and perform closed-loop control on...

AI Technical Summary

Problems solved by technology

[0004] ②The traditional levitation winding control is to control the levitation winding magnetic field by controlling the levitation winding current, and perform closed-loop control on the levitation current, thereby indirectly controlling the magnitude and direction of the levitation force required, which limits the accuracy and rapidity of levitation force control , there is a shortcoming of slow dynamic suspension response

[0005] ③The traditional suspension winding vector control requires the rotation coordinate transformation of the stator and rotor, and the control algorithm is complex

[0006] ④Traditional suspension winding control adopts current tracking inverter and sinusoidal pulse width modulation method (SPWM), the utilization rate of DC bus voltage is not high, the switching times of inverter switching devices are many, and the switching loss is high

[0007] ⑤The traditional levitation winding control adopts the double closed-loop control of displacement closed-loop and current closed-loop, which requires a current regulator. The system is too complicated, which limits the accuracy and rapidity of levitation force control and slow dynamic response

Images