420 lines
11 KiB
C
420 lines
11 KiB
C
#include <stdbool.h>
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#include <fxp.h>
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#include "power_switch.h"
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#include "measurement.h"
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#include "charge_pump.h"
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#include "rs485.h"
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#include "config.h"
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#include "charge_control.h"
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static const char *CHARGE_STATE_TEXT[] = {
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"WAIT_CHARGEPUMP",
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"INITIAL",
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"INITIAL_HOLD",
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"TRANSITION",
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"FLOAT",
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"SLEEP",
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"HIGH_TEMPERATURE"
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};
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static const char *DISCHARGE_STATE_TEXT[] = {
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"WAIT_CHARGEPUMP",
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"OK",
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"VOLTAGE_LOW",
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"OVERCURRENT"
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};
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static enum ChargeState charge_state;
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static enum DischargeState discharge_state;
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static bool charge_state_entered;
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static bool discharge_state_entered;
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static uint64_t charge_state_entered_timestamp;
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static uint64_t discharge_state_entered_timestamp;
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static fxp_t u_bat_regulation_corridor;
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static fxp_t u_bat_initial_full;
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static fxp_t u_bat_initial_low;
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static fxp_t u_bat_initial_hold_cancel;
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static fxp_t u_bat_float_full;
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static fxp_t u_bat_float_low;
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static fxp_t min_charge_pump_excess_voltage;
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static fxp_t u_bat_load_on;
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static fxp_t u_bat_load_off;
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static fxp_t load_current_limit;
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static fxp_t internal_temperature_limit;
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static fxp_t internal_temperature_recovery;
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static fxp_t sleep_solar_current;
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static fxp_t sleep_solar_excess_voltage;
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static enum ChargeState control_solar_charging(
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fxp_t corridor_high,
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fxp_t corridor_low,
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uint64_t uptime_ms,
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struct MeasurementResult *meas,
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enum ChargeState current_state,
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uint64_t time_in_state)
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{
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static uint64_t last_switch_change_time = 0;
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uint64_t solar_switch_onoff_duration = uptime_ms - last_switch_change_time;
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bool last_switch_state = power_switch_solar_status();
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if(meas->u_bat >= corridor_high) {
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power_switch_solar_off();
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} else if(meas->u_bat <= corridor_low) {
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power_switch_solar_on();
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}
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bool current_switch_state = power_switch_solar_status();
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if(last_switch_state != current_switch_state) { // switch changed
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last_switch_change_time = uptime_ms;
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solar_switch_onoff_duration = 0;
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}
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// temperature limit
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if(meas->avg_temperature > internal_temperature_limit) {
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return CHARGE_HIGH_TEMPERATURE;
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}
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// low-current limit (go to sleep at night)
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if((time_in_state > SLEEP_STATE_DELAY)
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&& (current_switch_state == true)
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&& (solar_switch_onoff_duration > SLEEP_SWITCH_DELAY)
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&& (meas->avg_i_solar < sleep_solar_current)) {
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return CHARGE_SLEEP;
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}
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return current_state;
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}
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static void solar_fsm_update(uint64_t uptime_ms, struct MeasurementResult *meas)
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{
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uint64_t charge_time_in_state = uptime_ms - charge_state_entered_timestamp;
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switch(charge_state) {
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case CHARGE_WAIT_CHARGEPUMP:
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// force the solar switch off until the charge pump voltage reaches a safe level.
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if(charge_state_entered) {
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power_switch_solar_off();
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}
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// calculate charge pump output excess voltage over battery voltage
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// and compare to the threshold
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if(fxp_sub(meas->u_sw, meas->u_bat) > min_charge_pump_excess_voltage) {
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charge_state = CHARGE_INITIAL;
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}
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break;
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case CHARGE_INITIAL:
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charge_state = control_solar_charging(
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u_bat_initial_full,
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u_bat_initial_low,
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uptime_ms,
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meas,
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charge_state,
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charge_time_in_state);
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// switch to hold state when high threshold is reached
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if(meas->u_bat >= u_bat_initial_full) {
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charge_state = CHARGE_INITIAL_HOLD;
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}
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break;
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case CHARGE_INITIAL_HOLD:
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charge_state = control_solar_charging(
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u_bat_initial_full,
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u_bat_initial_low,
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uptime_ms,
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meas,
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charge_state,
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charge_time_in_state);
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// cancel charge hold if battery voltage is below threshold
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if(meas->u_bat <= u_bat_initial_hold_cancel) {
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charge_state = CHARGE_INITIAL;
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}
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// time limit for initial hold charging
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if(charge_time_in_state > INITIAL_CHARGE_HOLD_TIME) {
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charge_state = CHARGE_TRANSITION;
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}
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break;
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case CHARGE_TRANSITION:
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// FIXME: dynamically adjust thresholds
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if(charge_time_in_state < INITIAL_TO_FLOAT_TRANSITION_TIME) {
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fxp_t u_bat_full =
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fxp_add(u_bat_initial_full,
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fxp_mult(
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fxp_sub(u_bat_float_full, u_bat_initial_full),
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fxp_div(charge_time_in_state, INITIAL_TO_FLOAT_TRANSITION_TIME)));
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fxp_t u_bat_low = fxp_sub(u_bat_full, u_bat_regulation_corridor);
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charge_state = control_solar_charging(
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u_bat_full,
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u_bat_low,
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uptime_ms,
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meas,
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charge_state,
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charge_time_in_state);
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} else {
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// time limit for transition to float charging reached
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charge_state = CHARGE_FLOAT;
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break;
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}
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break;
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case CHARGE_FLOAT:
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charge_state = control_solar_charging(
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u_bat_float_full,
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u_bat_float_low,
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uptime_ms,
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meas,
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charge_state,
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charge_time_in_state);
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// temperature limit
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if(meas->temperature > internal_temperature_limit) {
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charge_state = CHARGE_HIGH_TEMPERATURE;
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break;
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}
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// low-current limit (go to sleep at night)
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if(meas->i_solar < sleep_solar_current) {
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charge_state = CHARGE_SLEEP;
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break;
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}
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break;
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case CHARGE_SLEEP:
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if(charge_state_entered) {
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power_switch_solar_off();
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}
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{
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fxp_t solar_excess_voltage = fxp_sub(meas->u_solar, meas->u_bat);
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if(solar_excess_voltage > sleep_solar_excess_voltage) {
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// resume operation
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charge_state = CHARGE_WAIT_CHARGEPUMP;
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break;
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}
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}
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break;
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case CHARGE_HIGH_TEMPERATURE:
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if(charge_state_entered) {
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power_switch_solar_off();
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}
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if(meas->temperature < internal_temperature_recovery) {
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charge_state = CHARGE_WAIT_CHARGEPUMP;
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break;
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}
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break;
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default:
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// unknown state
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break;
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}
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}
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static void load_fsm_update(uint64_t uptime_ms, struct MeasurementResult *meas)
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{
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uint64_t discharge_time_in_state = uptime_ms - discharge_state_entered_timestamp;
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switch(discharge_state) {
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case DISCHARGE_WAIT_CHARGEPUMP:
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// force the load off until the charge pump voltage reaches a safe level.
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if(discharge_state_entered) {
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power_switch_load_off();
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}
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// calculate charge pump output excess voltage over battery voltage
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// and compare to the threshold
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if(fxp_sub(meas->u_sw, meas->u_bat) > min_charge_pump_excess_voltage) {
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discharge_state = DISCHARGE_OK;
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}
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break;
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case DISCHARGE_OK:
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// Battery voltage is in a safe range, so keep the load switched on
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if(discharge_state_entered) {
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power_switch_load_on();
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}
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if((meas->i_load > load_current_limit)
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&& (discharge_time_in_state > LOAD_CURRENT_INRUSH_TIME)) {
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discharge_state = DISCHARGE_OVERCURRENT;
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}
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if(meas->avg_u_bat < u_bat_load_off) {
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discharge_state = DISCHARGE_VOLTAGE_LOW;
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}
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break;
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case DISCHARGE_VOLTAGE_LOW:
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// Battery voltage is too low, so keep the load switched off
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if(discharge_state_entered) {
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power_switch_load_off();
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}
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// Can only switch on again after a specific amount of time has passed
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if((meas->avg_u_bat > u_bat_load_on)
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&& (discharge_time_in_state > LOAD_ON_DELAY)) {
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discharge_state = DISCHARGE_OK;
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}
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break;
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case DISCHARGE_OVERCURRENT:
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// Battery voltage is too low, so keep the load switched off
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if(discharge_state_entered) {
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power_switch_load_off();
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}
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// no way out except reset
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break;
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default:
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// unknown state
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break;
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}
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}
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void charge_control_init(void)
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{
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charge_state = CHARGE_WAIT_CHARGEPUMP;
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discharge_state = DISCHARGE_WAIT_CHARGEPUMP;
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charge_state_entered = true;
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discharge_state_entered = true;
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/* calculate thresholds */
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u_bat_regulation_corridor = fxp_div(FXP_FROM_INT(U_BAT_REGULATION_CORRIDOR),
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FXP_FROM_INT(1000));
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u_bat_initial_full = fxp_div(FXP_FROM_INT(U_BAT_INITIAL_FULL), FXP_FROM_INT(1000));
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u_bat_initial_low = fxp_sub(u_bat_initial_full, u_bat_regulation_corridor);
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u_bat_initial_hold_cancel = fxp_div(FXP_FROM_INT(U_BAT_INITIAL_HOLD_CANCEL), FXP_FROM_INT(1000));
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u_bat_float_full = fxp_div(FXP_FROM_INT(U_BAT_FLOAT_FULL), FXP_FROM_INT(1000));
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u_bat_float_low = fxp_sub(u_bat_float_full, u_bat_regulation_corridor);
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min_charge_pump_excess_voltage = fxp_div(FXP_FROM_INT(MIN_CHARGE_PUMP_EXCESS_VOLTAGE),
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FXP_FROM_INT(1000));
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u_bat_load_on = fxp_div(FXP_FROM_INT(U_BAT_LOAD_ON), FXP_FROM_INT(1000));
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u_bat_load_off = fxp_div(FXP_FROM_INT(U_BAT_LOAD_OFF), FXP_FROM_INT(1000));
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load_current_limit = fxp_div(FXP_FROM_INT(LOAD_CURRENT_LIMIT_MA), FXP_FROM_INT(1000));
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internal_temperature_limit = fxp_div(FXP_FROM_INT(INTERNAL_TEMPERATURE_LIMIT), FXP_FROM_INT(10));
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internal_temperature_recovery = fxp_div(FXP_FROM_INT(INTERNAL_TEMPERATURE_RECOVERY), FXP_FROM_INT(10));
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sleep_solar_current = fxp_div(FXP_FROM_INT(SLEEP_SOLAR_CURRENT), FXP_FROM_INT(1000));
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sleep_solar_excess_voltage = fxp_div(FXP_FROM_INT(SLEEP_SOLAR_EXCESS_VOLTAGE), FXP_FROM_INT(1000));
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}
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void charge_control_update(uint64_t uptime_ms, struct MeasurementResult *meas)
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{
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/* state change tracking for efficient transistions. */
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enum ChargeState last_charge_state = charge_state;
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enum DischargeState last_discharge_state = discharge_state;
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if(charge_state_entered) {
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rs485_enqueue("STATE:CHARGE:");
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rs485_enqueue(CHARGE_STATE_TEXT[charge_state]);
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rs485_enqueue("\n");
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charge_state_entered_timestamp = uptime_ms;
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}
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if(discharge_state_entered) {
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rs485_enqueue("STATE:DISCHG:");
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rs485_enqueue(DISCHARGE_STATE_TEXT[discharge_state]);
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rs485_enqueue("\n");
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discharge_state_entered_timestamp = uptime_ms;
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}
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/* generalized charge pump control */
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if(charge_state_entered || discharge_state_entered) {
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if(charge_state == CHARGE_WAIT_CHARGEPUMP
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|| discharge_state == DISCHARGE_WAIT_CHARGEPUMP) {
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// either charge or discharge control is waiting for the charge
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// pump, so power it up!
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charge_pump_start();
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} else if(((charge_state == CHARGE_SLEEP) || charge_control_is_charge_blocked())
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&& ((discharge_state == DISCHARGE_VOLTAGE_LOW) || charge_control_is_discharge_blocked())) {
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// no power from the solar panel and the battery voltage is too
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// low, so both switches are off and we can safely stop the charge
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// pump
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charge_pump_stop();
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}
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}
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solar_fsm_update(uptime_ms, meas);
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load_fsm_update(uptime_ms, meas);
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charge_state_entered = charge_state != last_charge_state;
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discharge_state_entered = discharge_state != last_discharge_state;
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}
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bool charge_control_is_idle(void)
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{
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return (((charge_state == CHARGE_SLEEP)
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|| (charge_state == CHARGE_HIGH_TEMPERATURE))
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&& ((discharge_state == DISCHARGE_VOLTAGE_LOW)
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|| (discharge_state == DISCHARGE_OVERCURRENT)));
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}
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bool charge_control_is_charge_blocked(void)
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{
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switch(charge_state) {
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case CHARGE_HIGH_TEMPERATURE:
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case CHARGE_WAIT_CHARGEPUMP:
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return true;
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default:
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return false;
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}
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}
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bool charge_control_is_discharge_blocked(void)
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{
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switch(discharge_state) {
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case DISCHARGE_OVERCURRENT:
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case DISCHARGE_WAIT_CHARGEPUMP:
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return true;
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default:
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return false;
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}
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}
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