• Introduction
• How to use
  • Enable the library
  • Requirement
  • Example of library use in combination with Library Quick start
• How to tweak the pid configuration ?
• Library structure

Introduction

OwnTech Power API Library PID provides a simple PID control for buck and boost in voltage mode.

This library automatically configures the driver modules required for the OwnTech Power Converter to work.

How to use

Enable the library

To enable the library, just uncomment the pid_voltage library in src/owntech.ini.

Then, include the library header in main.cpp:

#include "opalib_pid_voltage.h"

Memo: the standalone PID library configuration is as follows:

pid_voltage=https://gitlab.laas.fr/owntech/power-api/opalib-pid.git

Using OPALIB PID Voltage

• Add the following line to your main: #include "opalib_pid_voltage.h".
• Configure the core modules, e.g. using OPALIB Quick Start's init voltage function at the beginning of your main().
• Initialize the pid peripheral with opalib_pid_voltage_init_buck() or opalib_pid_voltage_init_boost() depending on the converter topology.
• Run the PID calculation with opalib_pid_voltage_calculation_and_pwm_update() in order to update the duty cycle in the PWM.

/**
 * @brief     This function Initialize all the parameters
 * needed for the PID calculation for the buck topoligy
 *
 * @param[in] vref      Reference voltage for the PID
 * @param[in] kp     kp for PID
 * @param[in] ki     ki for PID
 * @param[in] kd     kd for PID
 * @param[in] task_period_us Period of the PID calculation
 */
void opalib_pid_voltage_init_buck(float32_t vref, float32_t kp, float32_t ki, float32_t kd, uint32_t task_period_us);

/**
 * @brief     This function Initialize all the parameters
 * needed for the PID calculation for the buck topoligy
 *
 * @param[in] vref      Reference voltage for the PID
 * @param[in] kp     kp for PID
 * @param[in] ki     ki for PID
 * @param[in] kd     kd for PID
 * @param[in] task_period_us Period of the PID calculation
 */
void opalib_pid_voltage_init_boost(float32_t vref, float32_t kp, float32_t ki, float32_t kd, uint32_t task_period_us);

/**
 * @brief     This function calculation of the PID for the chosen 
 * topology and set the new duty cycle in the hrtim PWM
 */
void opalib_pid_voltage_calculation_and_pwm_update();

Depending on the chosen conversion topology, the controlled switch will be different.

Requirement

• The value of task_period_us must be the same value as the user task period used for opalib_quick_start.

Example of library use in combination with Library Quick start

#include "opalib_quick_start.h"
#include "opalib_pid_voltage.h"

void main(void)
{
    opalib_quick_start_init_voltage(opalib_pid_voltage_calculation_and_pwm_update, 50);
    opalib_pid_voltage_init_buck(12, 0.000215, 2.86, 0, 50);

    opalib_quick_start_launch_task();
}

How to tweak the pid configuration ?

• Open the opalib_pid_voltage.c file $(PROJECTDIR)/src/
• Modify GainADC1, offsetADC1, GainADC2 and offsetADC2 to change and calibrate the conversion of the ADC if the values converted are not coherent.

Library structure

• $(PROJECTDIR)/src/
  • opalib_pid_voltage.c Main source file
  • opalib_pid_voltage.h List of public functions implemented in library
  • data_conversion.c Internal use only
  • data_conversion.h Internal use only