Active discharge method for motor controller

Abstract

The invention discloses an active discharge method for a motor controller. The active discharge method comprises the steps of starting an active discharge function, controlling IGBTs of three lower bridge arms of an inverter to be opened at the same time and shorting a motor winding through the three lower bridge arms; and selecting a U-phase bridge arm as an active discharge bridge arm, controlling the opening cycle and the duty ratio of the IGBT of the upper bridge arm of the U-phase bridge arm and making the upper and lower bridge arms of the U-phase bridge arm through for discharging. Theupper bridge arms of the U-phase bridge arm are close to a cooling water channel of the controller. The condition that the pulse impact power of the active discharge bridge arm when the upper and lower bridge arms are through is within a set range is ensured through calculation and simulation. According to the active discharge method, the upper and lower bridge arms of using the IGBTs are throughfor discharging, the residual electric energy of a bus capacitor is converted into the desaturated energy of an IGBT module and the through periods and the duty ratios of the upper and lower bridge arms are controlled, so that the pulse impact power of the IGBT module is within an allowable range and the damage to IGBTs is avoided. According to the active discharge method, the design cost of hardware does not need to be increased, and the area of a PCB of the hardware and the space of the motor controller are saved.

Description

technical field [0001] The invention relates to the field of active discharge of electric vehicles, in particular to a low-cost active discharge method for a motor controller. Background technique [0002] In the prior art, an external active discharge resistor is used for active discharge, which requires additional peripheral circuit design and high hardware design costs. Contents of the invention [0003] The purpose of the present invention is to provide a low-cost active discharge method for a motor controller, which uses the upper and lower bridge arms of the inverter to discharge directly without increasing the hardware design cost. [0004] Technical scheme of the present invention is: [0005] An active discharge method for a motor controller. The motor controller is powered by a DC bus through a bus capacitor and an inverter. The inverter includes U, V, and W three-phase bridge arms composed of six IGBTs. Each The phase bridge arm includes an upper bridge arm an...

AI Technical Summary

Problems solved by technology

[0002] In the existing technology, the active discharge adopts the scheme of external active discharge resistor for discharge, which needs to increase the peripheral circuit design, and the hardware design cost is high

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