From 473253f5ab34e2cb8e206c2f5ed32620f1c5f3a4 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <thomas@tkolb.de>
Date: Wed, 17 Aug 2016 22:05:01 +0200
Subject: [PATCH] Some MPPT tweaks (not final yet)

---
 src/main.c | 70 +++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 53 insertions(+), 17 deletions(-)

diff --git a/src/main.c b/src/main.c
index 01f75dc..0b96eef 100644
--- a/src/main.c
+++ b/src/main.c
@@ -355,14 +355,17 @@ static void report_status(fxp_t vin, fxp_t vout, fxp_t current,
 
 int main(void)
 {
-	uint16_t cpuload = 0;
+	uint32_t cpuload = 0;
 	uint64_t timebase_ms = 0;
 	uint32_t time_in_state = 0;
 	char msg[128];
 	char number[FXP_STR_MAXLEN];
 	uint8_t sentSomething = 0;
 
+	fxp_t prevPower = 0;
+	int32_t prevPWM = 0;
 	int32_t pwm = 0;
+	int32_t mpp_step = 5;
 
 	enum OperState operState = Bootstrap;
 	enum OperState nextState = ConvConstVoltage;
@@ -378,6 +381,7 @@ int main(void)
 	fxp_t testPower[2];
 	int32_t testPWM[2];
 	int     testPWMStep = 5;
+	uint32_t next_power_test = 0;
 
 	uint32_t sleep_time = 10;
 	uint64_t force_display_update_time = 1000;
@@ -389,7 +393,7 @@ int main(void)
 	fxp_t PGAIN_CC = fxp_from_float( 50.000f);
 	fxp_t IGAIN_CC = fxp_from_float(  0.300f);
 
-	fxp_t CURRENT_THRESHOLD = fxp_from_float(0.002f);
+	fxp_t CURRENT_THRESHOLD = fxp_from_float(0.001f);
 
 	fxp_t AVG_FACT = fxp_from_float(0.10f);
 	fxp_t AVG_FACT_INV = fxp_sub(fxp_from_int(1), AVG_FACT);
@@ -537,7 +541,7 @@ int main(void)
 						timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
 					}
 
-					if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current < CURRENT_THRESHOLD) {
+					if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current_avg < CURRENT_THRESHOLD) {
 						operState = Bootstrap;
 						nextState = ConvConstVoltage;
 					}
@@ -582,7 +586,7 @@ int main(void)
 						timer_set_oc_value(TIM1, TIM_CH_CONV, 0);
 					}
 
-					if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current < CURRENT_THRESHOLD) {
+					if(time_in_state > 5000 && pwm > CONV_PWM_MAX && current_avg < CURRENT_THRESHOLD) {
 						operState = Bootstrap;
 						nextState = ConvConstCurrent;
 					}
@@ -600,7 +604,7 @@ int main(void)
 					// bootstrap off
 					timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
 
-					if((time_in_state % 50) == 0) {
+					if((time_in_state % 10) == 0) {
 						switch(testPWMStep) {
 							case 0:
 							case 2:
@@ -614,14 +618,28 @@ int main(void)
 								break;
 
 							case 4:
-								if(testPower[1] > testPower[0]) {
+								if(testPower[1] > prevPower) {
 									pwm = testPWM[1];
-								} else {
+									next_power_test = time_in_state + 10;
+									mpp_step++;
+								} else if(testPower[0] > prevPower) {
 									pwm = testPWM[0];
+									next_power_test = time_in_state + 10;
+									mpp_step++;
+								} else {
+									pwm = prevPWM;
+									next_power_test = time_in_state + 200;
+									mpp_step--;
 								}
 
-								if(pwm < (CONV_PWM_PERIOD/2)) {
-									pwm = 3 * CONV_PWM_PERIOD / 4;
+								if(mpp_step > 30) {
+									mpp_step = 30;
+								} else if(mpp_step < 1) {
+									mpp_step = 1;
+								}
+
+								if(pwm < CONV_PWM_MAX / 10) {
+									pwm = CONV_PWM_MAX / 10;
 								} else if(pwm > CONV_PWM_MAX) {
 									pwm = CONV_PWM_MAX;
 								}
@@ -630,12 +648,14 @@ int main(void)
 								break;
 
 							case 5:
-								// power test is currently idle, but power has changed
-								// too much.
-								// -> start a new one.
-								testPWM[0] = pwm + 4;
-								testPWM[1] = pwm - 3;
-								testPWMStep = 0;
+								// initiate a new power test
+								if(time_in_state >= next_power_test) {
+									testPWM[0] = pwm + mpp_step + 1;
+									testPWM[1] = pwm - mpp_step;
+									testPWMStep = 0;
+									prevPower = power_avg;
+									prevPWM = pwm;
+								}
 								break;
 
 							default:
@@ -643,12 +663,16 @@ int main(void)
 								break;
 						}
 
-						testPWMStep++;
+						if(testPWMStep < 5) {
+							testPWMStep++;
+						}
 					}
 
-					if(time_in_state > 5000 && current < CURRENT_THRESHOLD) {
+					if(time_in_state > 5000 && current_avg < CURRENT_THRESHOLD) {
 						operState = Bootstrap;
 						nextState = ConvMPP;
+						pwm = 8 * CONV_PWM_PERIOD / 10;
+						next_power_test = 0;
 					}
 
 					if(vout_avg > MAX_VOLTAGE) {
@@ -663,6 +687,18 @@ int main(void)
 						operState = Idle;
 					}
 
+#ifdef DEBUG
+					if((time_in_state % 100) == 0) {
+						debug_send_string("PWM: ");
+						fxp_format_int(pwm, msg);
+						debug_send_string(msg);
+						debug_send_string(" Step: ");
+						fxp_format_int(mpp_step, msg);
+						debug_send_string(msg);
+						sentSomething = 1;
+					}
+#endif
+
 					break;
 
 				case Idle: