Revision 0:0e9094f7b28d, committed 2020-03-08

Comitter:

f3d

Date:

Sun Mar 08 13:51:54 2020 +0000

Commit message:

Variable speed drive for the STM32F302 Nucleo with the ihm07m1 motor control board

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Mar 08 13:51:54 2020 +0000
@@ -0,0 +1,179 @@
+// This program allows the user to change the frequency of the three phase SPWM output
+// produced by TIM1.  The voltage ramps upwards with frequency.
+#include <stdint.h>
+#include "mbed.h"
+DigitalOut myled(LED1);
+/*
+PA8,9,10 are used to drive the PWM outputs.  They are also connected back to TIM_CH1,CH2,CH3 
+EN1,2,3 are pulled low and connected back to PC10,11,12
+PC13 = Blue button
+PB13 = User LED (I think - if not it is PA5)
+*/
+
+
+PwmOut PhA(PA_8);
+PwmOut PhB(PA_9);
+PwmOut PhC(PA_10);
+
+
+DigitalOut En1(PC_10);
+DigitalOut En2(PC_11);
+DigitalOut En3(PC_12);
+AnalogIn Pot(PB_1);
+Serial pc(USBTX, USBRX); // tx, rx useful for debugging
+volatile int CountA,CountB,CountC;
+
+#define FS 12000
+#define FC 72000000
+#define F_MOD_MIN 10
+#define F_MOD_MAX 100
+#define MAX_PWM_STEPS (FS/F_MOD_MIN)
+#define PI 3.141592f
+volatile int UpdatePending = 0;
+volatile uint32_t NSwitchesPerCycle;
+float AngleStep;
+float fm = 0; // modulation frequency
+float ami = 0; // Amplitude modulation index
+volatile uint16_t PWM_length;
+
+volatile uint16_t *PWM;
+volatile uint16_t PWMBuffer1[MAX_PWM_STEPS];
+volatile uint16_t PWMBuffer2[MAX_PWM_STEPS];
+
+
+void TimerISR(void)
+{
+    TIM1->CCR1 = PWM[CountA]; 
+    TIM1->CCR2 = PWM[CountB]; 
+    TIM1->CCR3 = PWM[CountC]; 
+    
+    CountB = (CountB + 1) % PWM_length;
+    CountC = (CountC + 1) % PWM_length;
+    TIM1->SR &= ~0x3f; // ack the interrupt    
+    CountA = (CountA + 1) % PWM_length;
+    if ( (CountA == 0) && UpdatePending )
+    {
+        if (PWM == PWMBuffer1) 
+            PWM = PWMBuffer2;
+        else        
+            PWM = PWMBuffer1;
+        CountA = 0;
+        CountB = PWM_length/3;
+        CountC = (2*PWM_length)/3;
+        PWM_length = NSwitchesPerCycle; 
+        UpdatePending = 0;
+    }
+
+}
+void initTimer1()
+{    
+    
+    TIM1->CR1 = 0; // make sure Counter is disabled before changing configuration
+    TIM1->CR2 = 0;
+    TIM1->PSC = 0; 
+    TIM1->ARR = (FC/FS)-1;
+    TIM1->CCR1 = 0; // 0% duty
+    TIM1->CCR2 = 0; // 0% duty
+    TIM1->CCR3 = 0; // 0% duty
+    // Enable timer outputs on channels 1,2,3
+    TIM1->CCER = (1 << 0) + (1 << 4) + (1 << 8);
+    TIM1->SR = 0;      // Clear flags.    
+    TIM1->CR1 |= 1; // enable counter
+
+    // Set up the interrupt handler
+    TIM1->DIER = 1; // Want update interrupt
+    NVIC_SetVector(TIM1_UP_TIM16_IRQn,(uint32_t) TimerISR);   
+    NVIC_EnableIRQ(TIM1_UP_TIM16_IRQn);
+    __enable_irq();   // enable interrupts */
+
+}
+void start()
+{
+    
+    TIM1->CCR1 = 0; // 0% duty
+    TIM1->CCR2 = 0; // 0% duty
+    TIM1->CCR3 = 0; // 0% duty
+    En1 = 1;
+    En2 = 1;
+    En3 = 1;
+    CountA = 0;
+    PWM_length = 6;
+    CountB = PWM_length / 3;
+    CountC = (2 *PWM_length) / 3;
+    for (int i=0;i<PWM_length;i++)
+    {
+        PWMBuffer1[i] = PWMBuffer2[i]= (FC/FS)/2; // set 50% duty for all values
+    }
+    PWM = PWMBuffer1;    
+}
+void updatePWM()
+{
+    float ami = Pot.read();
+    float fmi=ami; // maintain V/F = constant
+    uint16_t * UnusedPWMBuffer;
+    
+    if (PWM == PWMBuffer1) 
+    {
+        UnusedPWMBuffer = (uint16_t *)PWMBuffer2;
+    }
+    else
+    {
+        UnusedPWMBuffer = (uint16_t *)PWMBuffer1;
+    }
+    fm = fmi * F_MOD_MAX;
+    if (fm < F_MOD_MIN)
+    {
+        ami = 0;        
+        for (int i=0;i<PWM_length;i++)
+        {
+            UnusedPWMBuffer[i] = UnusedPWMBuffer[i]= (FC/FS)/2; // set 50% duty for all values
+        }
+        PWM = UnusedPWMBuffer;    
+        PWM_length = 6;
+    }
+    else
+    {
+        // Need to provide a voltage boost here to increase torque (motor stalls otherwise)
+        float amplitude = (1.5f*ami) * (FC/FS)/2; // Scale amplitude to ARR range
+        // The higher the frequency the greater the angle step size (similar to digital sampling
+        // The greatest number of steps occurs when we calculate a value for sine
+        
+        NSwitchesPerCycle = FS/fm;
+                
+        float AngleStep = 2.0f*PI / ((float)NSwitchesPerCycle);
+        
+        float Angle = 0;
+        
+        for (int i=0;i<NSwitchesPerCycle;i++)
+        {
+            float sine = (amplitude * sinf(Angle))+(FC/FS)/2;
+            if (sine > (FC/FS))
+                sine = (FC/FS);
+            if (sine < 0)
+                sine = 0;
+            UnusedPWMBuffer[i] = sine; // set 50% duty for all values
+            
+            Angle = Angle + AngleStep;
+        }
+        
+        UpdatePending = 1;
+        /* pc.printf("NSwitchesPerCycle = %d\r\n",NSwitchesPerCycle);
+        pc.printf("amplitude = %f\r\n",amplitude);
+        pc.printf("ARR = %d\r\n",TIM1->ARR);
+        pc.printf("---------------\r\n"); */
+    }
+    
+}
+int main() {
+    initTimer1();
+    start();
+    updatePWM();
+    while(1) {
+        wait(1); // wait for 200ms
+        myled = myled ^ 1; // Toggle the LED
+        updatePWM();
+        
+        
+
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Sun Mar 08 13:51:54 2020 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/mbed_official/code/mbed/builds/65be27845400
\ No newline at end of file