SwitchControl: auto-switching between MPPT and CV + more

- MPPT improved
- Status logging
- Smooth transition between MPPT and CV modes
  - MPPT -> CV, when target voltage is reached
  - CV -> MPPT, when regulation cannot hold target voltage due to
    insufficient source power
This commit is contained in:
Thomas Kolb 2023-01-16 23:10:49 +01:00
parent 4de016eb30
commit 4cd5266653
3 changed files with 211 additions and 61 deletions

View file

@ -9,7 +9,12 @@ pub enum LoggerError {
WriteError
}
pub struct Logger<D, P, const QLEN: usize>
pub trait Logger
{
fn log(&mut self, msg: &[u8]) -> Result<(), LoggerError>;
}
pub struct UartLogger<D, P, const QLEN: usize>
where
D: UartDevice,
P: ValidUartPinout<D>
@ -18,22 +23,13 @@ where
queue: Queue<u8, QLEN>,
}
impl<D, P, const QLEN: usize> Logger<D, P, QLEN>
impl<D, P, const QLEN: usize> Logger for UartLogger<D, P, QLEN>
where
D: UartDevice,
P: ValidUartPinout<D>
{
pub fn new(
uart: UartPeripheral<Enabled, D, P>
) -> Self
{
Logger::<D, P, QLEN> {
uart,
queue: Queue::new()
}
}
pub fn log(&mut self, msg: &[u8]) -> Result<(), LoggerError>
fn log(&mut self, msg: &[u8]) -> Result<(), LoggerError>
{
for c in msg.iter() {
match self.queue.enqueue(*c) {
@ -44,6 +40,23 @@ where
self.process().map(|_| ())
}
}
impl<D, P, const QLEN: usize> UartLogger<D, P, QLEN>
where
D: UartDevice,
P: ValidUartPinout<D>
{
pub fn new(
uart: UartPeripheral<Enabled, D, P>
) -> Self
{
UartLogger::<D, P, QLEN> {
uart,
queue: Queue::new()
}
}
pub fn log_fatal(&mut self, msg: &[u8])
{

View file

@ -44,6 +44,7 @@ mod ext_adc;
mod logger;
mod switch_control;
use logger::UartLogger;
use logger::Logger;
/// The linker will place this boot block at the start of our program image. We
@ -137,7 +138,7 @@ fn main() -> ! {
.unwrap();
// initialize the logger
let mut logger: Logger<_, _, 256> = Logger::new(uart);
let mut logger: UartLogger<_, _, 256> = UartLogger::new(uart);
logger.log(b"Logging initialized.\r\n").unwrap();
// Init PWMs
@ -216,7 +217,7 @@ fn main() -> ! {
pac::NVIC::unmask(pac::Interrupt::TIMER_IRQ_0);
}
let mut switchctrl = switch_control::SwitchControl::<1>::new(8000, SWITCH_PWM_LIMIT);
let mut switchctrl = switch_control::SwitchControl::<1>::new(8000, 100, SWITCH_PWM_LIMIT);
let mut loopcnt: u64 = 0;
@ -277,38 +278,44 @@ fn main() -> ! {
pwr_switch_ch.set_duty(pwmval as u16);
// do not output status data every loop
if loopcnt % 500 == 250 {
let mut data: String<16>;
match loopcnt % 500 {
1 => {
let mut data: String<16>;
logger.log(b"Vin: ").unwrap();
data = String::from(vin);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mV - Vout: ").unwrap();
data = String::from(vout);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mV - Iout: ").unwrap();
data = String::from(iout);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mA - Pout: ").unwrap();
data = String::from(vout * iout / 1000);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mW - raw: [").unwrap();
for i in 0..adc_value.len() {
data = String::from(adc_value[i]);
logger.log(b"Vin: ").unwrap();
data = String::from(vin);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mV - Vout: ").unwrap();
data = String::from(vout);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mV - Iout: ").unwrap();
data = String::from(iout);
logger.log(data.as_bytes()).unwrap();
logger.log(b"mA - Pout: ").unwrap();
data = String::from(vout * iout / 1000);
logger.log(data.as_bytes()).unwrap();
if i < 3 {
logger.log(b", ").unwrap();
logger.log(b"mW - raw: [").unwrap();
for i in 0..adc_value.len() {
data = String::from(adc_value[i]);
logger.log(data.as_bytes()).unwrap();
if i < 3 {
logger.log(b", ").unwrap();
}
}
}
logger.log(b"]; PWM: ").unwrap();
data = String::from(pwmval);
logger.log(data.as_bytes()).unwrap();
logger.log(b"]; PWM: ").unwrap();
data = String::from(pwmval);
logger.log(data.as_bytes()).unwrap();
logger.log(b"\r\n").unwrap();
logger.log(b"\r\n").unwrap();
},
2 => {
switchctrl.log_status(&mut logger);
},
_ => {}
}
loopcnt += 1;

View file

@ -1,3 +1,6 @@
use crate::logger::Logger;
use heapless::String;
enum ControlMode {
MPPT,
ConstantVoltage
@ -16,6 +19,10 @@ struct PID<const GAINSCALE: i32, const T0: i32>
iaccu_min: i32, // minimum allowed value in iaccu
iaccu_max: i32, // maximum allowed value in iaccu
dbg_p: i32,
dbg_i: i32,
dbg_d: i32,
}
impl<const GAINSCALE: i32, const T0: i32> PID<GAINSCALE, T0>
@ -31,10 +38,19 @@ impl<const GAINSCALE: i32, const T0: i32> PID<GAINSCALE, T0>
elast: 0,
target,
iaccu_min,
iaccu_max
iaccu_max,
dbg_p: 0,
dbg_i: 0,
dbg_d: 0
}
}
pub fn restart_from_output_value(&mut self, oval: i32)
{
self.iaccu = oval * GAINSCALE;
self.elast = 0;
}
pub fn update(&mut self, meas: i32) -> i32
{
let err = self.target - meas;
@ -50,10 +66,14 @@ impl<const GAINSCALE: i32, const T0: i32> PID<GAINSCALE, T0>
let pval = self.pgain * err / GAINSCALE;
let ival = self.iaccu / GAINSCALE;
let dval = self.dgain * (err - self.elast) / GAINSCALE;
let dval = self.dgain * (err - self.elast) / GAINSCALE / T0;
self.elast = err;
self.dbg_p = pval;
self.dbg_i = ival;
self.dbg_d = dval;
pval + ival + dval
}
@ -61,9 +81,24 @@ impl<const GAINSCALE: i32, const T0: i32> PID<GAINSCALE, T0>
{
self.target = new_target;
}
pub fn log_status(&self, logger: &mut dyn Logger)
{
let mut data: String<16>;
logger.log(b"Last P: ").unwrap();
data = String::from(self.dbg_p);
logger.log(data.as_bytes()).unwrap();
logger.log(b" I: ").unwrap();
data = String::from(self.dbg_i);
logger.log(data.as_bytes()).unwrap();
logger.log(b" D: ").unwrap();
data = String::from(self.dbg_d);
logger.log(data.as_bytes()).unwrap();
}
}
struct MPPT<const INTERVAL: u32, const PWR_TOLERANCE: i32>
struct MPPT<const INTERVAL: u32, const PERCENT_LOSS_TOLERANCE: i32>
{
update_delay: u32,
@ -71,24 +106,34 @@ struct MPPT<const INTERVAL: u32, const PWR_TOLERANCE: i32>
increment: i32,
last_power: i32,
peak_power: i32, // highest power seen so far. Decreases over time.
min_pwm: i32,
max_pwm: i32,
}
impl<const INTERVAL: u32, const PWR_TOLERANCE: i32> MPPT<INTERVAL, PWR_TOLERANCE>
impl<const INTERVAL: u32, const PERCENT_LOSS_TOLERANCE: i32> MPPT<INTERVAL, PERCENT_LOSS_TOLERANCE>
{
pub fn new(start_pwm: i32, min_pwm: i32, max_pwm: i32) -> Self
{
MPPT::<INTERVAL, PWR_TOLERANCE> {
MPPT::<INTERVAL, PERCENT_LOSS_TOLERANCE> {
update_delay: INTERVAL - 1,
pwm: start_pwm,
increment: 1,
last_power: 0,
peak_power: 0,
min_pwm,
max_pwm
max_pwm
}
}
pub fn restart(&mut self, start_pwm: i32, start_increment: i32)
{
self.peak_power = 1;
self.pwm = start_pwm;
self.increment = start_increment;
}
pub fn update(&mut self, vout: i32, iout: i32) -> i32
{
if self.update_delay == 0 {
@ -96,10 +141,20 @@ impl<const INTERVAL: u32, const PWR_TOLERANCE: i32> MPPT<INTERVAL, PWR_TOLERANCE
let cur_power = vout * iout;
let power_change = cur_power - self.last_power;
// decrease peak power over time
self.peak_power = (998 * (self.peak_power as i64) / 1000) as i32;
if cur_power > self.peak_power {
self.peak_power = cur_power;
} else if self.peak_power <= 0 {
self.peak_power = 1;
}
let peak_power_loss_percent = 100 - (100 * cur_power / self.peak_power);
// invert search direction if measured power is significantly lower than previous measurement
if power_change.abs() > PWR_TOLERANCE && cur_power < self.last_power {
if peak_power_loss_percent > PERCENT_LOSS_TOLERANCE {
//self.peak_power = cur_power; // prevent immediate turnaround
self.increment = -self.increment;
}
@ -121,42 +176,117 @@ impl<const INTERVAL: u32, const PWR_TOLERANCE: i32> MPPT<INTERVAL, PWR_TOLERANCE
self.pwm
}
pub fn log_status(&self, logger: &mut dyn Logger)
{
let mut data: String<16>;
match self.increment {
1 => logger.log(b"\xE2\x86\x91").unwrap(), // unicode for ↑
-1 => logger.log(b"\xE2\x86\x93").unwrap(), // unicode for ↓
_ => {
logger.log(b"inc: ").unwrap();
data = String::from(self.increment);
logger.log(data.as_bytes()).unwrap();
}
}
logger.log(b" Ppk: ").unwrap();
data = String::from(self.peak_power);
logger.log(data.as_bytes()).unwrap();
}
}
pub struct SwitchControl<const T0: i32>
{
mode: ControlMode,
mode_switch_delay_counter: u32,
cv_pid: PID<10000, T0>,
mppt: MPPT<20, 50000 /* microwatts */>,
pwm_max: i32
mppt: MPPT<20, 3 /* percent loss of peak power */>,
pwm_max: i32,
pwm_cur: i32,
cv_target: i32,
cv_max_deviation: i32
}
impl<const T0: i32> SwitchControl<T0>
{
pub fn new(cv_target: i32, pwm_max: i32) -> Self
pub fn new(cv_target: i32, cv_max_deviation: i32, pwm_max: i32) -> Self
{
SwitchControl::<T0> {
mode: ControlMode::MPPT,
cv_pid: PID::<10000, T0>::new(100, 50, 0, cv_target, 0, 0, pwm_max * 10000),
mppt: MPPT::<20, 50000>::new(pwm_max/2, 0, pwm_max),
pwm_max
mode_switch_delay_counter: 0,
cv_pid: PID::<10000, T0>::new(100, 50, 50, cv_target, 0, 0, pwm_max * 10000),
mppt: MPPT::<20, 3>::new(pwm_max/2, 0, pwm_max),
pwm_max,
pwm_cur: 0,
cv_target,
cv_max_deviation
}
}
// returns the new PWM value
pub fn update(&mut self, _vin: i32, vout: i32, iout: i32) -> i32
{
// Mode switching (only if delay counter has expired)
if self.mode_switch_delay_counter == 0 {
match self.mode {
ControlMode::MPPT =>
if vout > self.cv_target {
self.mode = ControlMode::ConstantVoltage;
self.cv_pid.restart_from_output_value(self.pwm_cur * 80 / 100);
// stay in CV mode for at least 100 update cycles
self.mode_switch_delay_counter = 100;
},
ControlMode::ConstantVoltage =>
if vout < self.cv_target - self.cv_max_deviation {
self.mode = ControlMode::MPPT;
// begin MPPT tracking by searching downwards, because the CV PID controller
// probably has pushed the PWM to the upper limit due to too low output
// voltage.
self.mppt.restart(self.pwm_cur, -1);
}
}
} else {
self.mode_switch_delay_counter -= 1;
}
// update the PWM value
let pwm = match self.mode {
ControlMode::ConstantVoltage => self.cv_pid.update(vout),
ControlMode::MPPT => self.mppt.update(vout, iout),
};
if pwm > self.pwm_max {
self.pwm_max
} else if pwm < 0 {
0
} else {
pwm
// store and limit pwm value
self.pwm_cur = pwm;
if self.pwm_cur > self.pwm_max {
self.pwm_cur = self.pwm_max;
} else if self.pwm_cur < 0 {
self.pwm_cur = 0;
}
self.pwm_cur
}
pub fn log_status(&self, logger: &mut dyn Logger)
{
match self.mode {
ControlMode::MPPT => {
logger.log(b"[MPPT] ").unwrap();
self.mppt.log_status(logger);
}
ControlMode::ConstantVoltage => {
logger.log(b"[CV] ").unwrap();
self.cv_pid.log_status(logger);
}
}
logger.log(b"\r\n").unwrap();
}
}