From 9e353c3248262557c17a71204e5784d517374c8e Mon Sep 17 00:00:00 2001
From: Thomas Kolb <thomas@tkolb.de>
Date: Sun, 21 Aug 2016 19:05:27 +0200
Subject: [PATCH] Limit max. PWM value in MPP if power is lost too often

---
 src/main.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/main.c b/src/main.c
index a3b4e24..23d86fd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -376,6 +376,8 @@ struct MPPState {
 
 	fxp_t powerAccu;
 	int32_t powerSamples;
+
+	int32_t mppMaxPWM;
 };
 
 #define MPP_TEST_DURATION 10 /* ms */
@@ -533,6 +535,8 @@ int main(void)
 	power_state.vout_avg = 0;
 	power_state.current_avg = 0;
 
+	mpp_state.mppMaxPWM = CONV_PWM_MAX;
+
 	init_clock();
 	init_rtc();
 	init_gpio();
@@ -719,18 +723,24 @@ int main(void)
 
 					mpp_run(time_in_state, &mpp_state, &power_state, &pwm);
 
-					if(pwm > CONV_PWM_MAX) {
-						pwm = CONV_PWM_MAX;
+					if(pwm > mpp_state.mppMaxPWM) {
+						pwm = mpp_state.mppMaxPWM;
 					} else if(pwm < CONV_PWM_PERIOD/100) {
 						pwm = CONV_PWM_PERIOD/100;
 					}
 
 					timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
 
+					if((mpp_state.mppMaxPWM < CONV_PWM_MAX) && (mpp_state.mppMaxPWM > CONV_PWM_MAX/10) &&
+							time_in_state > 5000 && ((time_in_state % 3000) == 10)) {
+						mpp_state.mppMaxPWM++;
+					}
+
 					if(time_in_state > 5000 && power_state.current_avg < CURRENT_THRESHOLD) {
 						operState = Bootstrap;
 						nextState = ConvMPP;
 						mpp_state.testIdx = -1;
+						mpp_state.mppMaxPWM -= 10;
 					}
 
 					if(power_state.vout_avg > MAX_VOLTAGE) {
@@ -743,6 +753,7 @@ int main(void)
 
 					if(power_state.vin_avg < power_state.vout_avg) {
 						operState = Idle;
+						mpp_state.mppMaxPWM = CONV_PWM_MAX;
 					}
 
 #ifdef DEBUG
@@ -750,6 +761,9 @@ int main(void)
 						debug_send_string("PWM: ");
 						fxp_format_int(pwm, msg);
 						debug_send_string(msg);
+						debug_send_string(" Limit: ");
+						fxp_format_int(mpp_state.mppMaxPWM, msg);
+						debug_send_string(msg);
 						sentSomething = 1;
 					}
 #endif