stm32f4单片机计算thd
时间: 2023-07-31 11:01:40 浏览: 163
首先,THD是“总谐波失真”(Total Harmonic Distortion)的缩写。计算THD对于STM32F4单片机来说,需要进行以下几个步骤:
1. 采集信号:通过STM32F4单片机的模数转换器(ADC)模块,将要测量的信号输入单片机。可以使用单片机的某个GPIO引脚接收外部信号,通过配置ADC工作模式和通道选择,将信号转换为数字形式,以便进行后续处理。
2. 信号处理:通过信号处理算法对采集到的信号进行预处理,包括滤波和采样率转换等。可以使用数字滤波器来消除噪音和杂散干扰,并通过差分运算放大器(PGA)来调整信号的幅度。
3. 谐波分析:利用FFT(快速傅里叶变换)算法对预处理后的信号进行频谱分析,计算出信号中的基波和各阶谐波的幅度。通过FFT可以将信号从时域转换到频域,得到频谱图,并可以从中提取出谐波分量。
4. THD计算:THD指标是衡量信号失真程度的重要参数。它表示所有谐波分量相对于基波分量的总和的百分比。在得到各阶谐波的幅度后,可以计算出THD值。THD计算公式为:THD = (sqrt(H2² + H3² + H4² + ... + Hn²) / H1) × 100%。其中,H1表示基波幅度,H2、H3、H4等表示各阶谐波幅度。
5. 结果输出:最后,将计算得到的THD值输出到显示屏、串口或其他外部设备上,以便用户查看和分析。
总之,通过适当的信号采集、预处理和谐波分析算法,结合STM32F4单片机的强大计算和通信能力,可以准确地计算出信号的THD值,以评估信号的失真程度。
相关问题
STM32F1 thd计算程序
以下是一个简单的STM32F1 THD计算程序:
```c
#include "stm32f10x.h"
#define SAMPLES 256
#define PI 3.14159265359
uint16_t adc_buffer[SAMPLES];
float thd;
void GPIO_Configuration(void);
void ADC_Configuration(void);
void TIM_Configuration(void);
int main(void) {
GPIO_Configuration();
ADC_Configuration();
TIM_Configuration();
while (1) {
}
}
void GPIO_Configuration(void) {
// Configure PC0 as analog input
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
void ADC_Configuration(void) {
// Configure ADC1
ADC_InitTypeDef ADC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1;
ADC_Init(ADC1, &ADC_InitStructure);
// Configure ADC1 channel 10 (PC0)
ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_55Cycles5);
// Enable ADC1
ADC_Cmd(ADC1, ENABLE);
// Start ADC1
ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}
void TIM_Configuration(void) {
// Configure TIM2 for 1ms timer interrupt
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_TimeBaseStructure.TIM_Period = 7199;
TIM_TimeBaseStructure.TIM_Prescaler = 999;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
// Enable TIM2 interrupt
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
TIM_Cmd(TIM2, ENABLE);
}
void TIM2_IRQHandler(void) {
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
// Read ADC buffer
for (int i = 0; i < SAMPLES; i++) {
adc_buffer[i] = ADC_GetConversionValue(ADC1);
}
// Calculate THD
float sum = 0;
float fundamental = 0;
for (int i = 0; i < SAMPLES; i++) {
float value = (float)adc_buffer[i] / 4096.0 * 3.3;
sum += value * value;
if (i == 0) {
fundamental = value;
}
}
sum -= fundamental * fundamental;
thd = sqrtf(sum) / fundamental;
TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
}
}
```
该程序配置了STM32F1的ADC和定时器,通过读取ADC缓冲区中的采样数据来计算THD。计算THD的过程是使用RMS计算基波和总谐波的平方和,然后除以基波的幅度,最后开平方根。在本例中,使用的是256个采样点,采样时间为55个时钟周期,采样频率为1.1kHz。
写一个STM32 C语言通过ADC采样计算THD的重新
下面是一个使用 STM32 的 C 语言编写的通过 ADC 采样计算 THD 的示例代码:
```c
#include "stm32f4xx.h"
#include "arm_math.h"
#define ADC1_DR_ADDRESS ((uint32_t)0x4001204C)
void ADC1_Init(void);
void TIM2_Init(void);
void GPIO_Init(void);
void NVIC_Configuration(void);
void Delay(__IO uint32_t nCount);
void CalculateTHD(void);
__IO uint16_t ADC1ConvertedValue[1024];
uint32_t SampleCount = 1024;
uint32_t THD = 0;
float32_t harmonic[51];
float32_t signal[1024];
int main(void)
{
ADC1_Init();
TIM2_Init();
GPIO_Init();
NVIC_Configuration();
while (1)
{
CalculateTHD();
}
}
void ADC1_Init(void)
{
ADC_InitTypeDef ADC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfConversion = 1;
ADC_Init(ADC1, &ADC_InitStructure);
ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_3Cycles);
ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
DMA_InitStructure.DMA_Channel = DMA_Channel_0;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_ADDRESS;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC1ConvertedValue;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_BufferSize = SampleCount;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA2_Stream0, &DMA_InitStructure);
DMA_Cmd(DMA2_Stream0, ENABLE);
ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);
ADC_Cmd(ADC1, ENABLE);
ADC_DMACmd(ADC1, ENABLE);
ADC_SoftwareStartConv(ADC1);
}
void TIM2_Init(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_TimeBaseStructure.TIM_Period = 999;
TIM_TimeBaseStructure.TIM_Prescaler = 83;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
TIM_Cmd(TIM2, ENABLE);
}
void GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOD, &GPIO_InitStructure);
}
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void DMA2_Stream0_IRQHandler(void)
{
GPIO_SetBits(GPIOD, GPIO_Pin_14);
DMA_ClearITPendingBit(DMA2_Stream0, DMA_IT_TC);
}
void Delay(__IO uint32_t nCount)
{
while (nCount--)
{
}
}
void CalculateTHD(void)
{
uint32_t i, j;
float32_t maxValue = 0.0;
float32_t squaredSum = 0.0;
float32_t rmsValue = 0.0;
for (i = 0; i < SampleCount; i++)
{
signal[i] = (float32_t)ADC1ConvertedValue[i] / 4095.0 * 3.3;
}
arm_rms_f32(signal, SampleCount, &rmsValue);
for (j = 1; j <= 50; j++)
{
maxValue = 0.0;
for (i = 0; i < SampleCount; i++)
{
harmonic[j] = harmonic[j] + signal[i] * arm_sin_f32(2.0 * PI * j * i / SampleCount);
}
harmonic[j] = harmonic[j] * 2.0 / SampleCount;
for (i = 0; i < SampleCount; i++)
{
squaredSum = squaredSum + arm_power_f32((signal[i] - harmonic[j] * arm_sin_f32(2.0 * PI * j * i / SampleCount)), 2.0);
}
THD = THD + (uint32_t)(100 * (arm_sqrt_f32(squaredSum / SampleCount) / rmsValue));
}
THD = THD / 50;
Delay(100);
}
```
该示例代码使用了 STM32 的 ADC 和 DMA 功能,采样 1024 个数据点,并通过计算得到了 THD 的值。该函数的实现过程如下:
1. 初始化 ADC 和 DMA,使其能够采样并存储数据。
2. 循环采样数据,计算其 RMS 值和谐波分量。
3. 计算 THD 值。
在计算 THD 值时,我们首先计算了每个谐波分量的值,然后计算了每个数据点与谐波分量之间的差值的平方和。最后,我们计算了 RMS 值并将其用作基准来计算 THD 值。
请注意,该示例代码仅供参考,并且可能需要根据你的具体应用场景进行修改。