利用MATLAB计算SPWM脉冲宽度与并应用STM32输出

2019-04-15 16:43发布生成海报

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转自光电科技协会王诚博
http://blog.csdn.net/wcb425499094/article/details/76703042
先上一张spwm波形生成原理图：

首先利用MATLAB产生三角波与正弦波叠加： [cpp] view plain copy print?

%% 产生正弦波与三角波叠加
y1=abs(sawtooth(a*2*pi*m,0.5));%三角波
y2=0.8*sin(a*pi);%正弦波
figure(1)
plot(a,y1,a,y2)

%% 产生正弦波与三角波叠加
y1=abs(sawtooth(a*2*pi*m,0.5));%三角波
y2=0.8*sin(a*pi);%正弦波
figure(1)
plot(a,y1,a,y2)

如图：

接着取交点,想了两种方法： 1.直接图片上取点，该方法不精确，毕竟只能目测和用鼠标点击。 [cpp] view plain copy print?

[X Y]=ginput(40)%图像中取点（不精确）
save('kuan','X');

[X Y]=ginput(40)%图像中取点（不精确）
save('kuan','X');

2.做差，使用阈值。 [cpp] view plain copy print?

for i=1:length(y1)%利用差值取点，设定阈值
if(abs(y1(i)-y2(i))<0.01)
X(P)=a(i);
P=P+1;
end
end

for i=1:length(y1)%利用差值取点，设定阈值
    if(abs(y1(i)-y2(i))<0.01)
        X(P)=a(i);
        P=P+1;
    end
end

阈值设置为0.001只取出20个点，但如上图应该有40个点，所以增大阈值，设为0.01。取出了200个点，如图：

放大观察：

可知每个交点取出了5个点，40个点刚好200个，所以假设正弦波与三角波交点附近正弦波斜率不变，所以采用平均的方法： [html] view plain copy print?

for i=0:m*4-1%取平均值
x(i+1)=(X((i+1)*5)+X(i*5+1))/2;
end

for i=0:m*4-1%取平均值
        x(i+1)=(X((i+1)*5)+X(i*5+1))/2;
end

然后就可以画出spwm波形： [cpp] view plain copy print?

%% 画出SPWM波形
for n=1:m*2
y3(1:floor(x(1)*10000))=0;
y3(floor(x(2*n-1)*10000):floor(x(2*n)*10000))=0.8;
if(n==20)
break
end
y3(floor(x(2*n)*10000):floor(x(2*(n+1)-1)*10000))=0;
y3(floor(x(40)*10000):length(y3))=0;
end
figure(4)
plot(a,y3)
axis([0 1 0 1])

%% 画出SPWM波形
for n=1:m*2
       y3(1:floor(x(1)*10000))=0;
       y3(floor(x(2*n-1)*10000):floor(x(2*n)*10000))=0.8;
       if(n==20)
       break
       end
       y3(floor(x(2*n)*10000):floor(x(2*(n+1)-1)*10000))=0;
       y3(floor(x(40)*10000):length(y3))=0;
end
figure(4)
plot(a,y3)
axis([0 1 0 1])

如图：

最后，计算正弦波半个周期的spwm的周期和占空比（使用stm32输出比较器输出pwm波）： [cpp] view plain copy print?

%% 计算SPWM的周期，占空比（利用输出比较器）
for i=1:m
tp(i)=(x(2*(i+1)-1)-x(2*i-1))*th;%spwm周期
ti(i)=(x(2*i)-x(2*i-1))*th;%脉冲宽度
end
tc=[floor(tp./max(tp)*255),fliplr(floor(tp./max(tp)*255))];%单片机定时器从1计到255（最大spwm周期）
dlmwrite('cycle.c',tc);%写入c文件
p=ti./tp;%计算spwm占空比
p1=[p fliplr(p)];%半个正弦波周期spwm的占空比序列
p1=floor(p1.*tc);%单片机定时器基准脉冲宽度
dlmwrite('dac_sinWave.c',p1);

%% 计算SPWM的周期，占空比（利用输出比较器）
for i=1:m
    tp(i)=(x(2*(i+1)-1)-x(2*i-1))*th;%spwm周期
    ti(i)=(x(2*i)-x(2*i-1))*th;%脉冲宽度
end
tc=[floor(tp./max(tp)*255),fliplr(floor(tp./max(tp)*255))];%单片机定时器从1计到255（最大spwm周期）
dlmwrite('cycle.c',tc);%写入c文件
p=ti./tp;%计算spwm占空比
p1=[p fliplr(p)];%半个正弦波周期spwm的占空比序列
p1=floor(p1.*tc);%单片机定时器基准脉冲宽度
dlmwrite('dac_sinWave.c',p1);

如果使用DAC描点： [cpp] view plain copy print?

b=floor(linspace(0,1,258)*10000);
for i=1:256
y4(i)=floor(y3(b(i+1))*4095);
end
dlmwrite('dac_SPWM.c',y4);

b=floor(linspace(0,1,258)*10000);
for i=1:256
y4(i)=floor(y3(b(i+1))*4095);
end
dlmwrite('dac_SPWM.c',y4);

但该方法速度太慢，而且单片机利用效率太低，所以舍弃。下面粘上MATLAB源代码： [cpp] view plain copy print?

%% 变量初始化
t=0.02;%正弦波周期
th=t/2;%半波周期
m=10;%三角波周期数
a=0:0.0001:1;
y3=0:0.0001:1;
P=1;
x=zeros(1);%分配空间
tp=zeros(1);
ti=zeros(1);
%% 产生正弦波与三角波叠加
y1=abs(sawtooth(a*2*pi*m,0.5));%三角波
y2=0.8*sin(a*pi);%正弦波
figure(1)
plot(a,y1,a,y2)
%% 取点
%[X Y]=ginput(40)%图像中取点（不精确）
% save('kuan','X');
for i=1:length(y1)%利用差值取点，设定阈值
if(abs(y1(i)-y2(i))<0.01)
X(P)=a(i);
P=P+1;
end
end
figure(2)
plot(a,y1,a,y2,X,1,'*')
for i=0:m*4-1%取平均值
x(i+1)=(X((i+1)*5)+X(i*5+1))/2;
end
figure(3)
plot(a,y1,a,y2,x,1,'*')
%% 画出SPWM波形
for n=1:m*2
y3(1:floor(x(1)*10000))=0;
y3(floor(x(2*n-1)*10000):floor(x(2*n)*10000))=0.8;
if(n==20)
break
end
y3(floor(x(2*n)*10000):floor(x(2*(n+1)-1)*10000))=0;
y3(floor(x(40)*10000):length(y3))=0;
end
figure(4)
plot(a,y3)
axis([0 1 0 1])
%% DAC描点法（速度太慢舍弃）
% b=floor(linspace(0,1,258)*10000);
% for i=1:256
% y4(i)=floor(y3(b(i+1))*4095);
% end
% dlmwrite('dac_SPWM.c',y4);
%% 计算SPWM的周期，占空比（利用输出比较器）
for i=1:m
tp(i)=(x(2*(i+1)-1)-x(2*i-1))*th;%spwm周期
ti(i)=(x(2*i)-x(2*i-1))*th;%脉冲宽度
end
tc=[floor(tp./max(tp)*255),fliplr(floor(tp./max(tp)*255))];%单片机定时器从1计到255（最大spwm周期）
dlmwrite('cycle.c',tc);%写入c文件
p=ti./tp;%计算spwm占空比
p1=[p fliplr(p)];%半个正弦波周期spwm的占空比序列
p1=floor(p1.*tc);%单片机定时器基准脉冲宽度
dlmwrite('dac_sinWave.c',p1);

%% 变量初始化
t=0.02;%正弦波周期
th=t/2;%半波周期
m=10;%三角波周期数
a=0:0.0001:1;
y3=0:0.0001:1;
P=1;
x=zeros(1);%分配空间
tp=zeros(1);
ti=zeros(1);
%% 产生正弦波与三角波叠加
y1=abs(sawtooth(a*2*pi*m,0.5));%三角波
y2=0.8*sin(a*pi);%正弦波
figure(1)
plot(a,y1,a,y2)
%% 取点
%[X Y]=ginput(40)%图像中取点（不精确）
% save('kuan','X');
for i=1:length(y1)%利用差值取点，设定阈值
    if(abs(y1(i)-y2(i))<0.01)
        X(P)=a(i);
        P=P+1;
    end
end
figure(2)
plot(a,y1,a,y2,X,1,'*')
for i=0:m*4-1%取平均值
        x(i+1)=(X((i+1)*5)+X(i*5+1))/2;
end
figure(3)
plot(a,y1,a,y2,x,1,'*')
%% 画出SPWM波形
for n=1:m*2
       y3(1:floor(x(1)*10000))=0;
       y3(floor(x(2*n-1)*10000):floor(x(2*n)*10000))=0.8;
       if(n==20)
       break
       end
       y3(floor(x(2*n)*10000):floor(x(2*(n+1)-1)*10000))=0;
       y3(floor(x(40)*10000):length(y3))=0;
end
figure(4)
plot(a,y3)
axis([0 1 0 1])
%% DAC描点法（速度太慢舍弃）
% b=floor(linspace(0,1,258)*10000);
% for i=1:256
% y4(i)=floor(y3(b(i+1))*4095);
% end
% dlmwrite('dac_SPWM.c',y4);
%% 计算SPWM的周期，占空比（利用输出比较器）
for i=1:m
    tp(i)=(x(2*(i+1)-1)-x(2*i-1))*th;%spwm周期
    ti(i)=(x(2*i)-x(2*i-1))*th;%脉冲宽度
end
tc=[floor(tp./max(tp)*255),fliplr(floor(tp./max(tp)*255))];%单片机定时器从1计到255（最大spwm周期）
dlmwrite('cycle.c',tc);%写入c文件
p=ti./tp;%计算spwm占空比
p1=[p fliplr(p)];%半个正弦波周期spwm的占空比序列
p1=floor(p1.*tc);%单片机定时器基准脉冲宽度
dlmwrite('dac_sinWave.c',p1);

stm32程序是用野火的例程改的，经过MATLAB计算得出周期与占空比（放入定时器的自动重装载寄存器ARR和比较寄存器CRR）： [cpp] view plain copy print?

uint8_t indexWave[] = {16,47,78,106,132,155,174,188,198,203,203,198,
188,174,155,132,106,78,47,16};
uint8_t indexcycle[] = {241,241,242,243,244,246,248,250,252,255,255,
252,250,248,246,244,243,242,241,241};

uint8_t indexWave[] = {16,47,78,106,132,155,174,188,198,203,203,198,
188,174,155,132,106,78,47,16};
uint8_t indexcycle[] = {241,241,242,243,244,246,248,250,252,255,255,
252,250,248,246,244,243,242,241,241};

在中断中改变寄存器的值（三路输出）： [cpp] view plain copy print?

TIM3->ARR = indexcycle[pwm_index];
TIM3->CCR2 = indexWave[pwm_index];
TIM3->CCR3 = indexWave[pwm_index];
TIM3->CCR4 = indexWave[pwm_index];
pwm_index++;

TIM3->ARR = indexcycle[pwm_index];	
TIM3->CCR2 = indexWave[pwm_index];	
TIM3->CCR3 = indexWave[pwm_index];	   
TIM3->CCR4 = indexWave[pwm_index];	
pwm_index++;

定时器配置 [cpp] view plain copy print?

/*基本定时器配置*/

/*基本定时器配置*/ [cpp] view plain copy print?

TIM_TimeBaseStructure.TIM_Period = 255;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  TIM_TimeBaseStructure.TIM_Period = 255;       							 
  TIM_TimeBaseStructure.TIM_Prescaler = 0;	    							
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;			
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

[cpp] view plain copy print?

/*PWM模式配置*/

/*PWM模式配置*/ [cpp] view plain copy print?

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 0;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; "font-family: Arial, Helvetica, sans-serif;">

	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;	    				
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;	
  TIM_OCInitStructure.TIM_Pulse = 0;										  			
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

[cpp] view plain copy print?

TIM_OC2Init(TIM3, &TIM_OCInitStructure);
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_OC3Init(TIM3, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_OC4Init(TIM3, &TIM_OCInitStructure);
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE);
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);
TIM_ITConfig(TIM3,TIM_IT_Update, ENABLE);
NVIC_Config_PWM();

TIM_OC2Init(TIM3, &TIM_OCInitStructure);
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
  
TIM_OC3Init(TIM3, &TIM_OCInitStructure);	
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
  
TIM_OC4Init(TIM3, &TIM_OCInitStructure);
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE);
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);	

TIM_ITConfig(TIM3,TIM_IT_Update, ENABLE);
		
NVIC_Config_PWM();

使用示波器观察得到SPWM输出：

看出这是SPWM波形。

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利用MATLAB计算SPWM脉冲宽度与并应用STM32输出
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