A method for suppressing speed re-throwing impact current of a high-speed permanent magnet synchronous motor

Abstract

This invention relates to a method for suppressing inrush current during high-speed permanent magnet synchronous motor re-start, belonging to the field of motor control technology. At the initial moment of re-start, the method calculates and assigns an initial value to the current loop integrator based on the motor voltage equation; adjusts the enabling sequence of each component of the control system during re-start; sets and maintains a safe d-q axis current setpoint based on the initial speed; and engages the speed loop to complete the re-start after the current loop stabilizes. Through multi-stage collaborative initialization and timing optimization, this invention significantly reduces the mismatch between the controller output voltage and the motor back EMF at the moment of re-start, thereby effectively suppressing inrush current and torque fluctuations, and achieving smooth and reliable high-speed re-start of the high-speed permanent magnet synchronous motor.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, and in particular to a method for suppressing the inrush current of a high-speed permanent magnet synchronous motor during speed-up re-start. Background Technology

[0002] High-speed permanent magnet synchronous motors are widely used in high-speed drive fields such as aerospace, flywheel energy storage, and precision manufacturing due to their advantages of high power density, high operating efficiency, and high reliability. In actual industrial applications, motor drive systems may experience unexpected shutdowns due to factors such as instantaneous fluctuations in the power grid, sudden load changes, control system misjudgments, or human error. However, production processes or system safety requirements do not allow for prolonged equipment shutdowns. Therefore, it is essential to quickly and smoothly put the motor back into operation while it is still rotating at high speed; this process is called "belt-speed re-start."

[0003] Permanent magnet synchronous motors (PMSMs) exhibit high back electromotive force (EMF) during high-speed rotation. Upon re-start, due to the dynamic response delay of the control system, the controller output voltage may not match the voltage command required for actual motor operation, leading to a large inrush current and impacting system stability and reliability. Therefore, researching inrush current suppression strategies suitable for high-speed PMSMs is crucial for achieving high-performance, high-efficiency belt-speed re-start control. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose a method for suppressing the inrush current of a high-speed permanent magnet synchronous motor during belt-speed re-start, which is applicable to belt-speed re-start of permanent magnet synchronous motors across the entire speed range, and has a particularly small impact at high speeds.

[0005] The technical problem solved by this invention is achieved through the following technical solution: A method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor includes the following steps: Step 1: At the re-start time, set the initial value for the integrator of the current loop regulator according to the voltage equation of the permanent magnet synchronous motor; Step 2: For a period of time after reactivation, the speed loop is not enabled, so that the speed loop output is zero. At this time, the dq axis current of the current loop is zero, and the current setpoint remains unchanged for a period of time after reactivation. Step 3: When the motor current response tends to stabilize, enable the speed loop to complete the belt speed re-engagement.

[0006] Furthermore, the voltage equation for the permanent magnet synchronous motor in step 1 is: in, u d and u qThis represents the voltage across the dq axis. i d and i q This represents the current in the dq axis system. L d and L q Indicates the inductance of the dq axis system. R s For stator resistance, ω e For rotor speed, ψ f It is a permanent magnet flux linkage.

[0007] Furthermore, the initial value of the current loop integrator in step 1 is: in, u d and u q This represents the voltage across the dq axis.

[0008] Moreover, the specific implementation method of step 2 is as follows: first, enable the SVPWM loop to calculate the duty cycle; after a delay of 2 cycles, enable the current loop and inverter output; the motor enters the current loop control state.

[0009] Furthermore, the specific implementation method of step 2 is as follows: in, i d and i q This represents the current in the dq axis system. U lim This indicates the inverter's maximum output voltage.

[0010] The advantages and positive effects of this invention are: This invention calculates and assigns an initial value to the current loop integrator based on the motor voltage equation at the initial moment of re-switching; adjusts the enabling sequence of each component of the control system during re-switching; sets and maintains a safe dq-axis current setpoint based on the initial speed; and engages the speed loop to complete the re-switching after the current loop stabilizes. This invention is applicable to belt-speed re-switching of permanent magnet synchronous motors across the entire speed range, with particularly low impact at high speeds. This invention effectively suppresses current and torque impacts during switching, especially effectively reducing the impact during switching at medium and high speeds. Attached Figure Description

[0011] Figure 1 This invention relates to a method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor. Figure 2The simulation waveform diagram shows the high-speed permanent magnet synchronous motor of the present invention being re-energized at 9000 r / min. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to the accompanying drawings.

[0013] A method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor. Figure 1 (a) is the switching signal at the moment of switching on / off in the traditional belt-speed re-switching method inverter, such as Figure 2 (b) shows the switching signal of the inverter according to the strategy of the present invention at the moment of switching, including the following steps: Step 1: At the re-start time, set the initial value for the integrator of the current loop regulator according to the voltage equation of the permanent magnet synchronous motor.

[0014] The voltage equation for the permanent magnet synchronous motor in step 1 is: in, u d and u q This represents the voltage across the dq axis. i d and i q This represents the current in the dq axis system. L d and L q Indicates the inductance of the dq axis system. R s For stator resistance, ω e For rotor speed, ψ f It is a permanent magnet flux linkage.

[0015] The initial value of the current loop integrator in step 1 is: in, u d and u q This represents the voltage across the dq axis.

[0016] Step 2: For a period of time after reactivation, the speed loop is initially disabled, making the speed loop output zero. At this time, the dq axis current setpoints of the current loop are both zero, and the current setpoints remain unchanged for a period of time after reactivation.

[0017] The specific implementation method of step 2 is as follows: First, enable the SVPWM loop to calculate the duty cycle; after a delay of 2 cycles, enable the current loop and inverter output; the motor enters the current loop control state.

[0018] The specific implementation method of step 3 is as follows: in, i d and i q This represents the current in the dq axis system. U lim This indicates the inverter's maximum output voltage.

[0019] Step 3: When the motor current response tends to stabilize, enable the speed loop to complete the belt speed re-engagement.

[0020] Based on the above-mentioned method for suppressing the impact current of a high-speed permanent magnet synchronous motor during re-start, simulation verification was performed using a high-speed permanent magnet synchronous motor. The main parameters of the motor are: rated speed 9000 r / min, rated current 17.2 A, stator resistance 0.17 Ω, dq shaft inductance 0.75 mH, number of pole pairs 2, and rotor flux linkage 0.073 Wb.

[0021] Figure 2 The simulation waveforms of a high-speed permanent magnet synchronous motor undergoing belt-speed re-start at 9000 r / min are shown, where (a) represents the traditional belt-speed re-start method and (b) represents the strategy described in this invention. It can be seen that the inrush current amplitude generated by the traditional belt-speed re-start method is close to 300A, far exceeding the motor's rated current, which will cause the motor to stop due to overcurrent protection. The inrush current generated by the belt-speed re-start method described in this invention is almost non-existent, and the torque fluctuation is less than 0.5 N·m. The strategy described in this invention can effectively suppress the inrush current generated by re-start.

[0022] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor, characterized in that: Includes the following steps: Step 1: At the re-start time, set the initial value for the integrator of the current loop regulator according to the voltage equation of the permanent magnet synchronous motor; Step 2: For a period of time after reactivation, the speed loop is not enabled, so that the speed loop output is zero. For a period of time after reactivation, the dq shaft current set value is set according to the initial speed of the motor, and the current set value is kept unchanged for a period of time after reactivation. Step 3: When the motor current response tends to stabilize, enable the speed loop to complete the belt speed re-engagement.

2. The method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor according to claim 1, characterized in that: The voltage equation for the permanent magnet synchronous motor in step 1 is: ； in, u d and u q This represents the voltage across the dq axis. i d and i q This represents the current in the dq axis system. L d and L q Indicates the inductance of the dq axis system. R s For stator resistance, ω e For rotor speed, ψ f It is a permanent magnet flux linkage.

3. The method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor according to claim 2, characterized in that: The initial value of the current loop integrator in step 1 is: ； in, u d and u q This represents the voltage across the dq axis.

4. The method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor according to claim 1, characterized in that: The specific implementation method of step 2 is as follows: First, enable the SVPWM loop to calculate the duty cycle; after a delay of 2 cycles, enable the current loop and inverter output; the motor enters the current loop control state.

5. The method for suppressing inrush current during high-speed re-start of a permanent magnet synchronous motor according to claim 1, characterized in that: The specific implementation method of step 2 is as follows: ； in, i d and i q This represents the current in the dq axis system. U lim This indicates the inverter's maximum output voltage.

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