From 8ed36f677011c64dfe12c7e39e3e121b599df212 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <thomas@tkolb.de>
Date: Sat, 3 Sep 2016 16:02:34 +0200
Subject: [PATCH] Some MPP tuning

---
 src/main.c | 49 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 38 insertions(+), 11 deletions(-)

diff --git a/src/main.c b/src/main.c
index 2510f37..ab60937 100644
--- a/src/main.c
+++ b/src/main.c
@@ -380,10 +380,13 @@ struct MPPState {
 	int32_t mppMaxPWM;
 };
 
-#define MPP_TEST_DURATION 10 /* ms */
+#define MPP_TEST_IGNORE_DURATION 5 /* ms */
+#define MPP_TEST_ACCU_DURATION 20 /* ms */
 
-#define MPP_TEST_STEPS 4
-const int32_t mpp_pwm_offsets[MPP_TEST_STEPS] = {-3, 4, -21, 20};
+#define MPP_TEST_DURATION (MPP_TEST_IGNORE_DURATION + MPP_TEST_ACCU_DURATION)
+
+#define MPP_TEST_STEPS 6
+const int32_t mpp_pwm_offsets[MPP_TEST_STEPS] = {-3, 4, -16, 15};
 
 static void mpp_run(
 		uint32_t time_in_state, struct MPPState *mpp_state,
@@ -410,14 +413,33 @@ static void mpp_run(
 		/* test running */
 
 		/* accumulation */
-		mpp_state->powerAccu = fxp_add(mpp_state->powerAccu,
-				fxp_mult(power_state->vout, power_state->current));
-		mpp_state->powerSamples++;
+		if(time_in_state > (mpp_state->nextTestStepTime - MPP_TEST_ACCU_DURATION)) {
+			mpp_state->powerAccu = fxp_add(mpp_state->powerAccu,
+					fxp_mult(power_state->vout, power_state->current));
+			mpp_state->powerSamples++;
+		}
 
 		if(time_in_state > mpp_state->nextTestStepTime) {
 			/* averaging */
 			mpp_state->powerAccu = fxp_div(mpp_state->powerAccu, fxp_from_int(mpp_state->powerSamples));
 
+#ifdef DEBUG
+			char msg[16];
+			debug_send_string("Accu: ");
+			fxp_format(mpp_state->powerAccu, msg, 3);
+			debug_send_string(msg);
+			debug_send_string(" ");
+			fxp_format_int(mpp_state->powerSamples, msg);
+			debug_send_string(msg);
+			debug_send_string(" PWM: ");
+			fxp_format_int(*pwm, msg);
+			debug_send_string(msg);
+			debug_send_string(" Idx: ");
+			fxp_format_int(mpp_state->testIdx, msg);
+			debug_send_string(msg);
+			debug_send_string("\r\n");
+#endif
+
 			if(mpp_state->powerAccu > mpp_state->maxPower) {
 				mpp_state->maxPower = mpp_state->powerAccu;
 				mpp_state->maxPWM = *pwm;
@@ -439,18 +461,19 @@ static void mpp_run(
 	} else if(mpp_state->testIdx == MPP_TEST_STEPS) {
 		/* finalize test */
 		if(mpp_state->maxPower > mpp_state->refPower) {
-			/* better PWM value found -> initiate new test to reach MPP */
-			mpp_state->testIdx = -1;
-
 			mpp_state->refPower = mpp_state->maxPower;
 			*pwm = mpp_state->maxPWM;
+
+			/* test again after a short time */
+			mpp_state->testIdx++;
+			mpp_state->nextTestStepTime = time_in_state + 250;
 		} else {
 			/* We were already at the maximum power point */
 			*pwm = mpp_state->refPWM;
 
 			/* test again after some time */
 			mpp_state->testIdx++;
-			mpp_state->nextTestStepTime = time_in_state + 5000;
+			mpp_state->nextTestStepTime = time_in_state + 20000;
 		}
 	} else {
 		/* no test active, just holding PWM */
@@ -526,7 +549,7 @@ int main(void)
 	fxp_t VOUT_SCALE = fxp_from_float(12.6f / 1620.0f);
 	fxp_t CURRENT_SCALE = fxp_from_float(9.01f / 4095.0f);
 
-	fxp_t CURRENT_OFFSET = fxp_from_float(0.049);
+	fxp_t CURRENT_OFFSET = fxp_from_float(0.045);
 
 	/* if power changes by more than this factor, MPP is tested again */
 	MPP_MAX_POWER_CHANGE_FACTOR = fxp_from_float(0.2f);
@@ -747,6 +770,8 @@ int main(void)
 							// limit has gone too low -> retry at maximum
 							mpp_state.mppMaxPWM = CONV_PWM_MAX;
 						}
+
+						pwm = mpp_state.mppMaxPWM;
 					}
 
 					if(power_state.vout_avg > MAX_VOLTAGE) {
@@ -797,7 +822,9 @@ int main(void)
 						lcd_send_string(")        ");
 						while(lcd_process() == 0); // send everything immediately
 
+#ifndef DEBUG
 						deepsleep(sleep_time);
+#endif
 
 						// Woke up again.
 						lcd_set_cursor_pos(0, 0);