基于STM32F767两路互补SPWM波(HAL库)
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2022-05-16 10:24:00
SPWM波指的是占空比呈正弦规律变化的PWM波,生成方式是在定时器中断中调整PWM波的占空比。 对于互补的两路SPWM波,一路为低电平 ‘0’ 时,另一路为高电平 ‘1’,即两路是互补的。 对于STM32F7,使用高级定时器TIM1可以方便地生成互补SPWM波。步骤如下: 1、确定载波周期 Tc,也 ......
spwm波指的是占空比呈正弦规律变化的pwm波,生成方式是在定时器中断中调整pwm波的占空比。
对于互补的两路spwm波,一路为低电平 ‘0’ 时,另一路为高电平 ‘1’,即两路是互补的。
对于stm32f7,使用高级定时器tim1可以方便地生成互补spwm波。步骤如下:
1、确定载波周期 tc,也即是每个spwm波的周期。对于逆变电路,常采用20khz,也即 tc = 50us;
2、确定基波周期 tb,此处取50hz,即 tb = 20ms;
3、计算取点数n,tb / tc = 20ms/50us = 4000;半个周期内则为 n = 2000点;
4、计算占空比,di = sin(i*pi / n), i = 1, 2, 3, ..., n;
5、确定最大最小占空比,例如最小占空比 dmin = 0,最大占空比dmax = 100%;
6、计算并修改定时器的比较值。将占空比为0%时,定时器的比较值设置为cmin = 0;将占空比为100%时,定时器的比较值设为cmax = 5399;则每中断一次,占空比的值设为 cmax*di,直接在中断里完成计算。
根据以上计算,可以修改最小占空比和最大占空比,也可以修改基波与载波频率。
以下是具体定时器配置与中断服务函数程序,基于stm32f767igbt:
//使用高级定时器 1 完成 //update--2019.6.3 //sin_k = tim1_arr / 200.0 * (float)(spwm_max_duty - spwm_min_duty ) ; //正弦波的比例系数,一个简单的数学代换 //sin_b = tim1_arr / 200.0 * (float)(spwm_max_duty + spwm_min_duty ) ; //正弦波的截距 #include "timer1.h" #include "led.h" #include "math.h" tim_handletypedef tim1_handler; //定时器句柄 tim_oc_inittypedef tim1_ch1handler; //定时器3通道4句柄 tim_breakdeadtimeconfigtypedef breakdeadtime_config; #define pwm_gpio gpioa #define pwm_pin1 gpio_pin_8 #define pwm_pin2 gpio_pin_7 #define tim1_arr 5399 //spwm波相关计算 //sin_points -- 一个周期内中断计算的正弦点数,20khz载波,tc = 50us,基波周期 tb = 50us * sin_points //tb = 20hz = 50ms = 50,000us, sin_points = 1000 //tb = 100hz = 10ms = 10,000us , sin_points = 200 //(-sin_k + sin_b ) / tim1_arr = spwm_min_duty % //( sin_k + sin_b ) / tim1_arr = spwm_max_duty %,反解出 sin_k, sin_b // sin_k = tim1_arr / 200.0 * (float)(spwm_max_duty - spwm_min_duty ) // sin_b = tim1_arr / 200.0 * (float)(spwm_max_duty + spwm_min_duty ) uint8_t spwm_min_duty = 10; //spwm波最小占空比 uint8_t spwm_max_duty = 90; //spwm波最大占空比 uint16_t count = 0; uint16_t sin_points = 200; uint16_t cc1_value; //比较寄存器 1的值,修改改变占空比 float sin_k,sin_b; //tim1 pwm部分初始化 //pwm输出初始化 //arr:自动重装值 //psc:时钟预分频数 void tim1_pwm_init(u16 arr,u16 psc) { //时钟配置 tim1_handler.instance = tim1; //定时器3 tim1_handler.init.prescaler = psc; //定时器分频 tim1_handler.init.countermode=tim_countermode_up;//向上计数模式 tim1_handler.init.period=arr; //自动重装载值 tim1_handler.init.clockdivision=tim_clockdivision_div1; hal_tim_pwm_init(&tim1_handler); //初始化pwm,会调用hal_tim_pwm_init(*) //pwm配置 tim1_ch1handler.ocmode=tim_ocmode_pwm1; //模式选择pwm1 tim1_ch1handler.pulse=arr/2; //设置比较值,此值用来确定占空比,默认比较值为自动重装载值的一半,即占空比为50% tim1_ch1handler.ocpolarity = tim_ocpolarity_high;//输出比较极性为高 tim1_ch1handler.ocnpolarity = tim_ocpolarity_high; tim1_ch1handler.ocidlestate = tim_ocidlestate_set; tim1_ch1handler.ocnidlestate = tim_ocidlestate_set; hal_tim_pwm_configchannel(&tim1_handler,&tim1_ch1handler,tim_channel_1);//配置tim1通道1 //死区时间配置 //https://blog.csdn.net/dzrywybl/article/details/82527889 breakdeadtime_config.offstaterunmode = tim_ossr_disable; breakdeadtime_config.offstateidlemode = tim_ossi_disable; breakdeadtime_config.locklevel = tim_locklevel_off; breakdeadtime_config.deadtime = 0x00; //0x00~0xff,当设置为0xff时,50us周期,约有4.68us死区时间;0x0f约有100ns死区时间 breakdeadtime_config.breakstate = tim_break_disable; breakdeadtime_config.breakpolarity = tim_breakpolarity_high; breakdeadtime_config.automaticoutput = tim_automaticoutput_disable; hal_timex_configbreakdeadtime(&tim1_handler, &breakdeadtime_config); //中断配置 hal_nvic_setpriority(tim1_cc_irqn,1,3); //设置中断优先级,抢占优先级1,子优先级3 hal_nvic_enableirq(tim1_cc_irqn); //开启itm3中断 //开启pwm并使能中断 hal_tim_pwm_start_it(&tim1_handler, tim_channel_1); //开启pwm输出并使能中断 hal_timex_pwmn_start(&tim1_handler, tim_channel_1); //打开互补通道 } //定时器底层驱动,时钟使能,引脚配置 //此函数会被hal_tim_pwm_init()调用 //htim:定时器句柄 void hal_tim_pwm_mspinit(tim_handletypedef *htim) { gpio_inittypedef gpio_initure; __hal_rcc_tim1_clk_enable(); //使能定时器3 __hal_rcc_gpioa_clk_enable(); __hal_rcc_gpiob_clk_enable(); gpio_initure.pin=pwm_pin1 | pwm_pin2; //pwm pin gpio_initure.mode=gpio_mode_af_pp; //复用推完输出 gpio_initure.pull=gpio_pullup; //上拉 gpio_initure.speed=gpio_speed_high; //高速 gpio_initure.alternate=gpio_af1_tim1; //pa8复用为tim1_ch1 hal_gpio_init(pwm_gpio,&gpio_initure); } //设置tim通道4的占空比 //compare:比较值 void tim_settim1compare1(u32 compare) { tim1->ccr1=compare; } //定时器1中断服务函数 void tim1_cc_irqhandler(void) //注意名称与通用计时器不同,多了 cc { hal_tim_irqhandler(&tim1_handler); } //定时器1中断服务函数调用 void hal_tim_oc_delayelapsedcallback(tim_handletypedef *htim) { if(htim==(&tim1_handler)) { count ++; if(count == sin_points) count = 0; sin_k = tim1_arr / 200.0 * (float)(spwm_max_duty - spwm_min_duty ) ; //正弦波的比例系数,一个简单的数学代换//更正为相减 sin_b = tim1_arr / 200.0 * (float)(spwm_max_duty + spwm_min_duty ) ; //正弦波的截距//更正为相加 cc1_value = (uint16_t) (sin_k * sin( (double)count * 6.28318 / (double)sin_points) + sin_b); //正弦值计算,得到spwm波占空比 tim_settim1compare1(cc1_value); } }
主函数配置为
tim1_pwm_init(5400-1,2-1); //216m / (5400 * 2 ) = 20k