A variable weight superposition overmodulation method for electric vehicle motor controller

Abstract

The invention discloses a variable weight superposition type overmodulation method for an electric vehicle motor controller, which belongs to the field of modulation technology, and comprises the steps of using a magnetic field orientation method to calculate and obtain the modulation coefficient; and obtaining the initial value of the superposition weight factor; according to the target voltage vector , calculate and obtain the phase angle of the target voltage vector in the stationary coordinate system; perform optimization calculations to obtain the optimal value of the stacking weight factor; calculate and obtain the weighted components for stacking according to the phase angle of the target voltage vector in the stationary coordinate system, and obtain the reference Voltage vector: According to the reference voltage vector and the space vector pulse width modulation method, the switching control signal of the inverter is calculated and obtained. The invention optimizes and calculates the superposition weight factor according to the target voltage vector phase angle, effectively reduces the harmonic distortion rate of the motor phase current and the torque ripple of the drive system, and improves the power output performance of the electric vehicle and the comfort of drivers and passengers.

Description

technical field [0001] The invention relates to the technical field of modulation, in particular to a variable-weight superposition-additive overmodulation method for an electric vehicle motor controller. Background technique [0002] The new energy vehicle motor controller usually adopts the space vector pulse width modulation method (SVPWM) to calculate the control signal of the inverter IGBT switch to realize the torque control of the drive system. The theoretical working area of ​​the motor controller includes linear modulation region and nonlinear overmodulation region. The working area of ​​the traditional motor drive system is limited to the linear modulation region and the shallow nonlinear overmodulation region, which does not fully utilize the voltage output capability of the controller, resulting in low voltage utilization. When the controller works in the deep nonlinear overmodulation region, there will be a sudden change in the phase angle of the voltage vector...

AI Technical Summary

Problems solved by technology

The working area of ​​the traditional motor drive system is limited to the linear modulation area and the shallow non-linear over-modulation area, which does not make full use of the voltage output capability of the controller, resulting in low voltage utilization

When the controller works in the deep nonlinear overmodulation region, there will be a sudden change in the phase angle of the voltage vector, which will cause a sharp increase in the harmonic distortion rate of the phase current, resulting in torque ripple in the motor drive system, affecting the power output performance of new energy vehicles and The comfort of the driver and passengers, the traditional overmodulation algorithm has not made targeted optimization for this

The existing electric drive systems of new energy vehicles mainly have the following disadvantages: most of them cannot operate in the deep over-modulation region, and the voltage utilization rate is low; some electric drive systems with over-modulation algorithms use theoretical calculation methods, which have a large amount of calculation and are not applicable For engineering applications; some overmodulation algorithms use the weight superposition calculation method to reduce the calculation amount of the algorithm, but when the voltage vector crosses the center line of the modulation sector, there will be a sudden change in the phase angle of the voltage vector, which will cause a sharp increase in the harmonic distortion rate of the phase current, resulting in a The problem of torque ripple in the drive system affects the power output performance of new energy vehicles and the comfort of drivers and passengers

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