说明：  能量回馈母线电压升高原因分析。做电机控制时，分析了6个开关管开通关闭瞬间电流的方向，说明为什么制动是母线电压会升高。 是我自己的想法，如果有异议，欢迎邮箱联系。
(when motor brake, it will cause bus voltage rise. analysis the reason. analysis the direction of the instantaneous current of six switches, and the reason why the bus voltage rises is explained. its a person thought, if you disagree, the correction is welcomed.)