New approach to MPP tracking
Test multiple points for PWM, switch to the one which gives the most power, repeat. If two consecutive tests give the same point, hold that for some time or until power changes too much.
This commit is contained in:
parent
473253f5ab
commit
9dc1ab928c
2
fxplib
2
fxplib
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@ -1 +1 @@
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Subproject commit 035e7ecda497b408a5791ba20a0906b913dfef45
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Subproject commit 3bd86806d72a6caed2b604a0ba4c6bf344f72b1a
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254
src/main.c
254
src/main.c
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@ -325,22 +325,30 @@ static void init_systick(int freq)
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}
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#endif
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static void report_status(fxp_t vin, fxp_t vout, fxp_t current,
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struct PowerState {
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fxp_t vin, vin_avg;
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fxp_t vout, vout_avg;
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fxp_t current, current_avg;
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fxp_t power_avg;
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};
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static void report_status(struct PowerState *power_state,
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int32_t pwm, enum OperState operState)
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{
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char number[FXP_STR_MAXLEN];
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debug_send_string("DATA:");
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fxp_format(vin, number, 3);
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fxp_format(power_state->vin, number, 3);
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debug_send_string(number);
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debug_send_string(":");
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fxp_format(vout, number, 3);
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fxp_format(power_state->vout, number, 3);
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debug_send_string(number);
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debug_send_string(":");
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fxp_format(current, number, 3);
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fxp_format(power_state->current, number, 3);
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debug_send_string(number);
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debug_send_string(":");
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@ -353,6 +361,94 @@ static void report_status(fxp_t vin, fxp_t vout, fxp_t current,
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debug_send_string("\r\n");
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}
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fxp_t MPP_MAX_POWER_CHANGE_FACTOR;
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struct MPPState {
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int32_t testIdx; /* -1, if test requested, 0..MPP_TEST_STEPS-1 if running, >=MPP_TEST_STEPS if finished */
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uint32_t nextTestStepTime;
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fxp_t refPower;
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int32_t refPWM;
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fxp_t maxPower;
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int32_t maxPWM;
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};
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#define MPP_TEST_DURATION 25 /* ms */
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#define MPP_TEST_STEPS 4
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const int32_t mpp_pwm_offsets[MPP_TEST_STEPS] = {-51, -4, 5, 50};
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static void mpp_run(
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uint32_t time_in_state, struct MPPState *mpp_state,
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struct PowerState *power_state, int32_t *pwm)
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{
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fxp_t power_change;
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fxp_t power_change_factor;
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if(mpp_state->testIdx == -1) {
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/* initiate new test */
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mpp_state->refPower = power_state->power_avg;
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mpp_state->nextTestStepTime = time_in_state + MPP_TEST_DURATION; /* time to give averagers to settle */
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mpp_state->testIdx = 0;
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mpp_state->refPWM = *pwm;
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mpp_state->maxPower = 0;
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mpp_state->maxPWM = *pwm;
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*pwm = *pwm + mpp_pwm_offsets[0];
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} else if(mpp_state->testIdx < MPP_TEST_STEPS) {
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/* test running */
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if(time_in_state > mpp_state->nextTestStepTime) {
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if(power_state->power_avg > mpp_state->maxPower) {
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mpp_state->maxPower = power_state->power_avg;
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mpp_state->maxPWM = *pwm;
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}
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mpp_state->testIdx++;
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if(mpp_state->testIdx < MPP_TEST_STEPS) {
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*pwm = mpp_state->refPWM + mpp_pwm_offsets[mpp_state->testIdx];
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mpp_state->nextTestStepTime = time_in_state + MPP_TEST_DURATION;
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}
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}
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} else if(mpp_state->testIdx == MPP_TEST_STEPS) {
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/* finalize test */
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if(mpp_state->maxPower > mpp_state->refPower) {
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/* better PWM value found -> initiate new test to reach MPP */
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mpp_state->testIdx = -1;
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mpp_state->refPower = mpp_state->maxPower;
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*pwm = mpp_state->maxPWM;
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} else {
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/* We were already at the maximum power point */
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*pwm = mpp_state->refPWM;
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/* test again after some time */
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mpp_state->testIdx++;
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mpp_state->nextTestStepTime = time_in_state + 5000;
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}
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} else {
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/* no test active, just holding PWM */
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/* initiate new test after defined time */
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if(time_in_state > mpp_state->nextTestStepTime) {
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mpp_state->testIdx = -1;
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}
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/* initiate new test if power changes too much */
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power_change = fxp_abs(fxp_sub(mpp_state->refPower, power_state->power_avg));
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power_change_factor = fxp_div(power_change, mpp_state->refPower);
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if(power_change_factor > MPP_MAX_POWER_CHANGE_FACTOR) {
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mpp_state->testIdx = -1;
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}
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}
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}
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int main(void)
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{
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uint32_t cpuload = 0;
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@ -362,27 +458,18 @@ int main(void)
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char number[FXP_STR_MAXLEN];
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uint8_t sentSomething = 0;
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fxp_t prevPower = 0;
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int32_t prevPWM = 0;
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int32_t pwm = 0;
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int32_t mpp_step = 5;
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enum OperState operState = Bootstrap;
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enum OperState nextState = ConvConstVoltage;
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enum OperState lastState = operState;
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fxp_t vin, vout, current;
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fxp_t vin_avg = 0, vout_avg = 0, current_avg = 0;
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struct PowerState power_state;
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struct MPPState mpp_state;
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fxp_t pErr = 0, iErr = 0;
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fxp_t controlAction = 0;
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fxp_t power_avg;
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fxp_t testPower[2];
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int32_t testPWM[2];
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int testPWMStep = 5;
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uint32_t next_power_test = 0;
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uint32_t sleep_time = 10;
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uint64_t force_display_update_time = 1000;
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@ -420,6 +507,13 @@ int main(void)
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fxp_t CURRENT_OFFSET = fxp_from_float(0.049);
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/* if power changes by more than this factor, MPP is tested again */
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MPP_MAX_POWER_CHANGE_FACTOR = fxp_from_float(0.1f);
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power_state.vin_avg = 0;
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power_state.vout_avg = 0;
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power_state.current_avg = 0;
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init_clock();
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init_rtc();
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init_gpio();
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@ -446,13 +540,13 @@ int main(void)
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if(timebase_ms == force_display_update_time) {
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lcd_set_cursor_pos(1, 0);
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fxp_format(vin_avg, number, 1);
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fxp_format(power_state.vin_avg, number, 1);
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fxp_right_align(number, msg, 4, ' ');
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lcd_send_string("I:");
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lcd_send_string(msg);
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lcd_send_string("V ");
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fxp_format(vout_avg, number, 2);
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fxp_format(power_state.vout_avg, number, 2);
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fxp_right_align(number, msg, 5, ' ');
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lcd_send_string("O:");
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lcd_send_string(msg);
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@ -460,7 +554,7 @@ int main(void)
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lcd_set_cursor_pos(0, 10);
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fxp_format(power_avg, number, 2);
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fxp_format(power_state.power_avg, number, 2);
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fxp_right_align(number, msg, 5, ' ');
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lcd_send_string(msg);
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lcd_send_string("W");
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@ -488,25 +582,25 @@ int main(void)
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dma_clear_interrupt_flags(DMA1, DMA_CHANNEL1, DMA_TCIF);
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// convert read values
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vin = fxp_mult(fxp_from_int(adc_values[0]), VIN_SCALE);
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vout = fxp_mult(fxp_from_int(adc_values[1]), VOUT_SCALE);
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current = fxp_mult(fxp_from_int(adc_values[2]), CURRENT_SCALE);
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current = fxp_sub(current, CURRENT_OFFSET);
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power_state.vin = fxp_mult(fxp_from_int(adc_values[0]), VIN_SCALE);
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power_state.vout = fxp_mult(fxp_from_int(adc_values[1]), VOUT_SCALE);
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power_state.current = fxp_mult(fxp_from_int(adc_values[2]), CURRENT_SCALE);
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power_state.current = fxp_sub(power_state.current, CURRENT_OFFSET);
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vin_avg = fxp_add(fxp_mult(vin, AVG_FACT), fxp_mult(vin_avg, AVG_FACT_INV));
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vout_avg = fxp_add(fxp_mult(vout, AVG_FACT), fxp_mult(vout_avg, AVG_FACT_INV));
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current_avg = fxp_add(fxp_mult(current, AVG_FACT), fxp_mult(current_avg, AVG_FACT_INV));
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power_state.vin_avg = fxp_add(fxp_mult(power_state.vin, AVG_FACT), fxp_mult(power_state.vin_avg, AVG_FACT_INV));
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power_state.vout_avg = fxp_add(fxp_mult(power_state.vout, AVG_FACT), fxp_mult(power_state.vout_avg, AVG_FACT_INV));
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power_state.current_avg = fxp_add(fxp_mult(power_state.current, AVG_FACT), fxp_mult(power_state.current_avg, AVG_FACT_INV));
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power_avg = fxp_mult(vout_avg, current_avg);
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power_state.power_avg = fxp_mult(power_state.vout_avg, power_state.current_avg);
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// Main FSM
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if(timebase_ms >= 1000) {
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switch(operState) {
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case Bootstrap:
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// enable bootstrap pulse with very low duty cycle
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// disable converter
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 48);
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// enable bootstrap pulse with very low duty cycle
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timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 48);
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if(time_in_state >= 5) { // bootstrap duration in ms
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iErr = fxp_div(IERR_LIMIT, fxp_from_int(2));
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@ -519,7 +613,7 @@ int main(void)
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
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// calculate error values
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pErr = fxp_sub(CONST_VOLTAGE, vout_avg);
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pErr = fxp_sub(CONST_VOLTAGE, power_state.vout_avg);
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iErr = fxp_add(iErr, pErr);
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// limit integral error range
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@ -541,20 +635,20 @@ int main(void)
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timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
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}
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if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current_avg < CURRENT_THRESHOLD) {
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if(time_in_state > 5000 && pwm > CONV_PWM_MAX && power_state.current_avg < CURRENT_THRESHOLD) {
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operState = Bootstrap;
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nextState = ConvConstVoltage;
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}
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if(time_in_state > 1000 && vout_avg < MPP_VOLTAGE_THR) {
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if(time_in_state > 1000 && power_state.vout_avg < MPP_VOLTAGE_THR) {
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operState = ConvMPP;
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}
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if(current_avg > MAX_CURRENT) {
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if(power_state.current_avg > MAX_CURRENT) {
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operState = ConvConstCurrent;
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}
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if(vin_avg < vout_avg) {
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if(power_state.vin_avg < power_state.vout_avg) {
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operState = Idle;
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}
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break;
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@ -564,7 +658,7 @@ int main(void)
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
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// calculate error values
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pErr = fxp_sub(MAX_CURRENT, current_avg);
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pErr = fxp_sub(MAX_CURRENT, power_state.current_avg);
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iErr = fxp_add(iErr, pErr);
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// limit integral error range
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@ -586,16 +680,16 @@ int main(void)
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timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
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}
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if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current_avg < CURRENT_THRESHOLD) {
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if(time_in_state > 5000 && pwm > CONV_PWM_MAX && power_state.current_avg < CURRENT_THRESHOLD) {
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operState = Bootstrap;
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nextState = ConvConstCurrent;
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}
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if(time_in_state > 1000 && current_avg < MPP_CURRENT_THR) {
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if(time_in_state > 1000 && power_state.current_avg < MPP_CURRENT_THR) {
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operState = ConvMPP;
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}
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if(vout_avg > MAX_VOLTAGE) {
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if(power_state.vout_avg > MAX_VOLTAGE) {
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operState = ConvConstVoltage;
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}
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break;
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@ -604,86 +698,31 @@ int main(void)
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// bootstrap off
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
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if((time_in_state % 10) == 0) {
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switch(testPWMStep) {
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case 0:
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case 2:
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pwm = testPWM[testPWMStep/2];
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timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
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break;
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mpp_run(time_in_state, &mpp_state, &power_state, &pwm);
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case 1:
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case 3:
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testPower[testPWMStep/2] = power_avg;
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break;
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case 4:
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if(testPower[1] > prevPower) {
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pwm = testPWM[1];
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next_power_test = time_in_state + 10;
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mpp_step++;
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} else if(testPower[0] > prevPower) {
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pwm = testPWM[0];
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next_power_test = time_in_state + 10;
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mpp_step++;
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} else {
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pwm = prevPWM;
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next_power_test = time_in_state + 200;
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mpp_step--;
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}
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if(mpp_step > 30) {
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mpp_step = 30;
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} else if(mpp_step < 1) {
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mpp_step = 1;
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}
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if(pwm < CONV_PWM_MAX / 10) {
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pwm = CONV_PWM_MAX / 10;
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} else if(pwm > CONV_PWM_MAX) {
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pwm = CONV_PWM_MAX;
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}
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timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
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break;
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case 5:
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// initiate a new power test
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if(time_in_state >= next_power_test) {
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testPWM[0] = pwm + mpp_step + 1;
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testPWM[1] = pwm - mpp_step;
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testPWMStep = 0;
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prevPower = power_avg;
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prevPWM = pwm;
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}
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break;
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default:
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testPWMStep = 4;
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break;
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}
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if(testPWMStep < 5) {
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testPWMStep++;
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}
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if(pwm > CONV_PWM_MAX) {
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pwm = CONV_PWM_MAX;
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} else if(pwm < CONV_PWM_PERIOD/100) {
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pwm = CONV_PWM_PERIOD/100;
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}
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if(time_in_state > 5000 && current_avg < CURRENT_THRESHOLD) {
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timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
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if(time_in_state > 5000 && power_state.current_avg < CURRENT_THRESHOLD) {
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operState = Bootstrap;
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nextState = ConvMPP;
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pwm = 8 * CONV_PWM_PERIOD / 10;
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next_power_test = 0;
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mpp_state.testIdx = -1;
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}
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if(vout_avg > MAX_VOLTAGE) {
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if(power_state.vout_avg > MAX_VOLTAGE) {
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operState = ConvConstVoltage;
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}
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if(current_avg > MAX_CURRENT) {
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if(power_state.current_avg > MAX_CURRENT) {
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operState = ConvConstCurrent;
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}
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if(vin_avg < vout_avg) {
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if(power_state.vin_avg < power_state.vout_avg) {
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operState = Idle;
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}
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@ -692,9 +731,6 @@ int main(void)
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debug_send_string("PWM: ");
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fxp_format_int(pwm, msg);
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debug_send_string(msg);
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debug_send_string(" Step: ");
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fxp_format_int(mpp_step, msg);
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debug_send_string(msg);
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sentSomething = 1;
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}
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#endif
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@ -706,7 +742,7 @@ int main(void)
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timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
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timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
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if(time_in_state > 1000 && vin_avg > fxp_add(vout_avg, WAKEUP_OFFSET_VOLTAGE)) {
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if(time_in_state > 1000 && power_state.vin_avg > fxp_add(power_state.vout_avg, WAKEUP_OFFSET_VOLTAGE)) {
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sleep_time = 10;
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operState = Bootstrap;
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nextState = ConvMPP;
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@ -783,7 +819,7 @@ int main(void)
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}
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if((timebase_ms % 1000) == 490) {
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report_status(vin_avg, vout_avg, current_avg, pwm, operState);
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report_status(&power_state, pwm, operState);
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}
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// cpu load = timer1 value after main loop operations
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||||
|
|
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Reference in a new issue