关于DCDC直流开关电源采集输出电压ADC后反馈到PWM的占空比来稳定输出的问题

暴走的晟哥哥

我对原子哥的历程中的PWM输出实验和ADC实验进行了改动和组合 首先不加反馈  是可以进行pwm输出和ADC测量显示的

[mw_shl_code=c,true]int main(void) { u16 adcx; float led0pwmval=250; NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//?è????????????????·?×é2 delay_init(168); //?????????±???? uart_init(115200); //???????®???¨??????115200 LED_Init(); //??????LED LCD_Init(); //??????LCD???? Adc_Init(); //??????ADC TIM14_PWM_Init (500-1,8-1); POINT_COLOR=RED; LCD_ShowString(30,50,200,16,16,"Explorer STM32F4"); LCD_ShowString(30,70,200,16,16,"ADC TEST"); LCD_ShowString(30,90,200,16,16,"ATOM@ALIENTEK"); LCD_ShowString(30,110,200,16,16,"2014/5/6"); POINT_COLOR=BLUE;//?è??×????????? LCD_ShowString(30,130,200,16,16,"ADC1_CH5_VAL:"); LCD_ShowString(30,150,200,16,16,"ADC1_CH5_VOL:0.000V"); //???????¨?????????????? while(1) { adcx=Get_Adc_Average(ADC_Channel_5,20);//?????¨??5??×???????20???????ù LCD_ShowxNum(134,130,adcx,4,16,0); //????ADCC???ù?ó???????? temp=(float)adcx*(3.3/4096); //?????????ó??????????????????????±???3.1111 adcx=temp; //??????????·???adcx±??????ò??adcx??u16???? LCD_ShowxNum(134,150,adcx,1,16,0); //??????????????????·???3.1111???°??????????????3 temp-=adcx; //°?????????????????·?????????????????·???±???3.1111-3=0.1111 temp*=1000; //??????·?????1000????????0.1111??×?????111.1???à?±??±????????????? LCD_ShowxNum(150,150,temp,3,16,0X80); //??????????·??¨?°??×????????????????©????????????????111. LED0=!LED0; TIM_SetCompare1(TIM14,led0pwmval); delay_ms(10); } } [/mw_shl_code]

然后我的想法是  首先如上的代码是输出一个21KHZ，占空比50%的PWM波，然后我会在程序中设置一个我需要输出的电压值，根据ADC采集的当前输出电压来和当前这50%占空比来计算出当前的输入电压，之后根据当前的输入电压和理想输出电压来计算我需要的占空比来改变led0pwmval来改变PWM的占空比。   代码如下

[mw_shl_code=c,true]int main(void) { u16 adcx; float led0pwmval=250; float temp; float Voutideal=3; float zkb; NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//?è????????????????·?×é2 delay_init(168); //?????????±???? uart_init(115200); //???????®???¨??????115200 LED_Init(); //??????LED LCD_Init(); //??????LCD???? Adc_Init(); //??????ADC TIM14_PWM_Init (500-1,8-1); POINT_COLOR=RED; LCD_ShowString(30,50,200,16,16,"Explorer STM32F4"); LCD_ShowString(30,70,200,16,16,"ADC TEST"); LCD_ShowString(30,90,200,16,16,"ATOM@ALIENTEK"); LCD_ShowString(30,110,200,16,16,"2014/5/6"); POINT_COLOR=BLUE;//?è??×????????? LCD_ShowString(30,130,200,16,16,"ADC1_CH5_VAL:"); LCD_ShowString(30,150,200,16,16,"ADC1_CH5_VOL:0.000V"); //???????¨?????????????? while(1) { adcx=Get_Adc_Average(ADC_Channel_5,20);//?????¨??5??×???????20???????ù LCD_ShowxNum(134,130,adcx,4,16,0); //????ADCC???ù?ó???????? temp=(float)adcx*(3.3/4096); //?????????ó??????????????????????±???3.1111 adcx=temp; //??????????·???adcx±??????ò??adcx??u16???? LCD_ShowxNum(134,150,adcx,1,16,0); //??????????????????·???3.1111???°??????????????3 temp-=adcx; //°?????????????????·?????????????????·???±???3.1111-3=0.1111 temp*=1000; //??????·?????1000????????0.1111??×?????111.1???à?±??±????????????? LCD_ShowxNum(150,150,temp,3,16,0X80); //??????????·??¨?°??×????????????????©????????????????111. LED0=!LED0; TIM_SetCompare1(TIM14,led0pwmval); zkb=(500-led0pwmval)/500; led0pwmval=500-((500*Voutideal*zkb)/temp); delay_ms(10); } } [/mw_shl_code]

即为我想要的输出为3V，来改变PWM的占空比，但是改完之后可以读取ADC，但PWM不输出了，不知道错误出在哪里，希望大家可以帮助我一下。
我是为了做大学生电子竞赛来学习的这些知识，目前还是小白一个，所以希望大家能说的简单一些，让我这个小白尽量理解，谢谢了。

shihantu

1. 进入调试模式检查输出值是否有效 , 明显 L28 和 L30 有问题 .

2. 开关电源没这么简单的 , 如果你不懂 ID , 建议好好看一下自动控制原理 , 虽然 ID 在这里用不是太合适 , 高等数学也要相当扎实 .

暴走的晟哥哥

回复【2楼】shihantu:
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L28 和L30是指第28和30行么？   那个是在LCD上显示采集电压的代码，对运算时没有效果的，其实可以删除的 我觉得可能是在pwm和adc的频率有问题   还有就是34-39行的问题

暴走的晟哥哥

[mw_shl_code=c,true]void Adc_Init(void) { GPIO_InitTypeDef GPIO_InitStructure; ADC_CommonInitTypeDef ADC_CommonInitStructure; ADC_InitTypeDef ADC_InitStructure; RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//????GPIOA?±?? RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //????ADC1?±?? //????????ADC1?¨??5 IO?? GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;//PA5 ?¨??5 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;//???????? GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;//?????????? GPIO_Init(GPIOA, &GPIO_InitStructure);//?????? RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,ENABLE); //ADC1???? RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,DISABLE); //?????á?? ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;//???????? ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;//???????ù?×???®????????5???±?? ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled; //DMA?§?? ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div4;//?¤·???4·?????ADCCLK=PCLK2/4=84/4=21Mhz,ADC?±??×???????????36Mhz ADC_CommonInit(&ADC_CommonInitStructure);//?????? ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;//12?????? ADC_InitStructure.ADC_ScanConvMode = DISABLE;//·??¨?è???? ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;//??±?????×??? ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;//??????·??ì?????????í????·? ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;//?????? ADC_InitStructure.ADC_NbrOfConversion = 1;//1??×????????ò?ò???? ????????×??????ò?ò??1 ADC_Init(ADC1, &ADC_InitStructure);//ADC?????? ADC_Cmd(ADC1, ENABLE);//????AD×????÷ } //????ADC?? //ch: @ref ADC_channels //?¨???? 0~16????·??§????ADC_Channel_0~ADC_Channel_16 //·?????:×????á?? u16 Get_Adc(u8 ch) { //?è?????¨ADC?????ò×é?¨?????????ò???????ù?±?? ADC_RegularChannelConfig(ADC1, ch, 1, ADC_SampleTime_480Cycles ); //ADC1,ADC?¨??,480??????,?á?????ù?±???????á?????·?? ADC_SoftwareStartConv(ADC1); //???????¨??ADC1???í??×??????????? while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC ));//????×????á?? return ADC_GetConversionValue(ADC1); //·???×??ü????ADC1???ò×é??×????á?? } //?????¨??ch??×?????????times??,???ó???ù //ch:?¨??±à?? //times:???????? //·?????:?¨??ch??times??×????á?????ù?? u16 Get_Adc_Average(u8 ch,u8 times) { u32 temp_val=0; u8 t; for(t=0;t<times;t++) { temp_val+=Get_Adc(ch); delay_ms(5); } return temp_val/times;//???ù?????? } [/mw_shl_code]

这是ADC.C

[mw_shl_code=c,true]void TIM14_PWM_Init(u32 arr,u32 psc) { //????·??è????????IO???è?? GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14,ENABLE); //TIM14?±?????? RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //????PORTF?±?? GPIO_PinAFConfig(GPIOA,GPIO_PinSource7,GPIO_AF_TIM14); //GPIOF9???????¨?±?÷14 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //GPIOF9 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //???????? GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //????100MHz GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //???ì???????? GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //???? GPIO_Init(GPIOA,&GPIO_InitStructure); //??????PF9 TIM_TimeBaseStructure.TIM_Prescaler=psc; //?¨?±?÷·??? TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //?ò?????????? TIM_TimeBaseStructure.TIM_Period=arr; //×?????×°???? TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM14,&TIM_TimeBaseStructure);//???????¨?±?÷14 //??????TIM14 Channel1 PWM???? TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //?????¨?±?÷????:TIM?????í???÷??????2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±??????????? TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //????????:TIM????±????????? TIM_OC1Init(TIM14, &TIM_OCInitStructure); //?ù??T???¨???????????????èTIM1 4OC1 TIM_OC1PreloadConfig(TIM14, TIM_OCPreload_Enable); //????TIM14??CCR1?????¤×°???????÷ TIM_ARRPreloadConfig(TIM14,ENABLE);//ARPE???? TIM_Cmd(TIM14, ENABLE); //????TIM14 } [/mw_shl_code]

这是PWM.C

shihantu

回复【3楼】暴走的晟哥哥:
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L28 和 L30 把 temp 减到 0 了 , 你说没影响 ???

printf参与反馈环的采样时间 , 这点就不需要看你其他代码了 , 自动控制大忌 .

暴走的晟哥哥

回复【5楼】shihantu:
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嗯  我也发现了  现在改成了在LCD代码之前改变占空比了  就避免了temp的改变  谢谢您了

喜滋滋

楼主，你是怎么解决的，我现在也遇到了和你相同的问题