定时器的参数发生了变化？还是你用了多个定时器干扰了？

        TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
        TIM_OCInitTypeDef  TIM_OCInitStructure;
        GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);

        TIM_TimeBaseStructure.TIM_Period = Period;
        TIM_TimeBaseStructure.TIM_Prescaler = 0;
        TIM_TimeBaseStructure.TIM_ClockDivision = 0;
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
        TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
        TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
        TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
        TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
        TIM_OC1Init(TIM3, &TIM_OCInitStructure);
        TIM_SelectOutputTrigger(TIM3,TIM_TRGOSource_Update);
        TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable);
        TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
        TIM_ARRPreloadConfig(TIM3, ENABLE);

        TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
        TIM_OCInitTypeDef  TIM_OCInitStructure;
        GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);

        TIM_TimeBaseStructure.TIM_Period = Period;
        TIM_TimeBaseStructure.TIM_Prescaler = 0;
        TIM_TimeBaseStructure.TIM_ClockDivision = 0;
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
        TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

        TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
        TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
        TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
        TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
        TIM_OC1Init(TIM3, &TIM_OCInitStructure);
        //TIM_OC2Init(TIM3, &TIM_OCInitStructure);
        TIM_SelectOutputTrigger(TIM3,TIM_TRGOSource_Update);
        TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable);
        TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
        //TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
        TIM_ARRPreloadConfig(TIM3, ENABLE);

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