通过检测电流电压的大小,改变斩波电路的PWM信号的脉宽,以实现稳压目的。
单片机源程序如下:
- #include "PID.h"
- u8 m=0;
- u16 adn=0;
- char b[20];
- typedef struct PID
- {
- int SetPoint;
- float Kp;
- float Ki;
- float Kd;
- int NowError; //当前误差
- int LastError; //上次误差
- int PrevError; //上上次误差
- double OUT;
- }PID;
- static PID sPID;
- static PID *sptr = &sPID;
- void PID_Init(void)
- {
- sptr->NowError = 0;
- sptr->LastError = 0;
- sptr->PrevError = 0;
- sptr->Kp = 2;
- sptr->Ki= 0;
- sptr->Kd = 0;
- sptr->SetPoint = 1241; //1241/4096*3.3=1V
- sptr->OUT = 0;
- }
- int PIDCal(u16 actually)
- {
- register int ep,ei,ed,zout;
- sptr->NowError = sptr->SetPoint - actually; //设定值-实际值
- ep = sptr->NowError - sptr->LastError;
- ei = sptr->NowError;
- ed = sptr->NowError - 2*sptr->LastError + sptr->PrevError;
- zout = sptr->Kp * ep + sptr->Ki * ei + sptr->Kd * ed;
- sptr->OUT+=zout;
- sptr->PrevError = sptr->LastError;
- sptr->LastError = sptr->NowError;
- if(sptr->OUT<360) sptr->OUT=360;
- if(sptr->OUT>3240) sptr->OUT=3240;
- return(sptr->OUT);
- }
- void TIM2_init()
- {
- TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
- NVIC_InitTypeDef NVIC_InitStruct;
-
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
-
- TIM_TimeBaseInitStruct.TIM_Period = 4999;
- TIM_TimeBaseInitStruct.TIM_Prescaler = 71;
- TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
- TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStruct);
-
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
- NVIC_InitStruct.NVIC_IRQChannel = TIM2_IRQn;
- NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
- NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
- NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
- NVIC_Init(&NVIC_InitStruct);
-
- TIM_ClearFlag(TIM2,TIM_FLAG_Update);
- TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
-
- TIM_Cmd(TIM2,ENABLE);
- }
- void TIM2_IRQHandler()
- {
- u16 adv;
- if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
- {
- TIM_ClearITPendingBit(TIM2,TIM_FLAG_Update);
- if(m<3)
- {
- adn+=AD_read();
- m++;
- }
- else
- {
- adv=adn/4;
- TIM3->CCR1 = PIDCal(adv);
- adn=0;m=0;
- }
- }
- }
复制代码- #include "PWM.h"
- void PWM_init(u16 a,u16 b)
- {
- GPIO_InitTypeDef GPIO_InitStruct;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
- TIM_OCInitTypeDef TIM_OCInitStructure;
-
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO,ENABLE);
-
- GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6;
- GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP ;
- GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOA,&GPIO_InitStruct);
-
- TIM_TimeBaseInitStruct.TIM_Period = a;
- TIM_TimeBaseInitStruct.TIM_Prescaler = b;
- TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
- TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
- TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStruct);
-
- TIM_OCInitStructure.TIM_Pulse = 1799;
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //选择定时器模式:TIM脉冲宽度调制模式2
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
- TIM_OC1Init(TIM3, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM3 OC2
- TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR2上的预装载寄存器
-
- TIM_Cmd(TIM3,ENABLE);
- }
复制代码
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