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config/custom_components/versatile_thermostat/pi_algorithm.py

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+# pylint: disable=line-too-long
+""" The PI algorithm implementation """
+
+import logging
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class PITemperatureRegulator:
+    """A class implementing a PI Algorithm
+    PI algorithms calculate a target temperature by adding an offset which is calculating as follow:
+    - offset = kp * error + ki * accumulated_error
+
+    To use it you must:
+    - instanciate the class and gives the algorithm parameters: kp, ki, offset_max, stabilization_threshold, accumulated_error_threshold
+    - call calculate_regulated_temperature with the internal and external temperature
+    - call set_target_temp when the target temperature change.
+    """
+
+    def __init__(
+        self,
+        target_temp: float,
+        kp: float,
+        ki: float,
+        k_ext: float,
+        offset_max: float,
+        stabilization_threshold: float,
+        accumulated_error_threshold: float,
+    ):
+        self.target_temp: float = target_temp
+        self.kp: float = kp  # proportionnel gain
+        self.ki: float = ki  # integral gain
+        self.k_ext: float = k_ext  # exterior gain
+        self.offset_max: float = offset_max
+        self.stabilization_threshold: float = stabilization_threshold
+        self.accumulated_error: float = 0
+        self.accumulated_error_threshold: float = accumulated_error_threshold
+
+    def reset_accumulated_error(self):
+        """Reset the accumulated error"""
+        self.accumulated_error = 0
+
+    def set_accumulated_error(self, accumulated_error):
+        """Allow to persist and restore the accumulated_error"""
+        self.accumulated_error = accumulated_error
+
+    def set_target_temp(self, target_temp):
+        """Set the new target_temp"""
+        self.target_temp = target_temp
+        # Discussion #191. After a target change we should reset the accumulated error which is certainly wrong now.
+        # Discussion #384. Finally don't reset the accumulated error but smoothly reset it if the sign is inversed
+        # if self.accumulated_error < 0:
+        #     self.accumulated_error = 0
+
+    def calculate_regulated_temperature(
+        self, room_temp: float, external_temp: float
+    ):  # pylint: disable=unused-argument
+        """Calculate a new target_temp given some temperature"""
+        if room_temp is None:
+            _LOGGER.warning(
+                "Temporarily skipping the self-regulation algorithm while the configured sensor for room temperature is unavailable"
+            )
+            return self.target_temp
+        if external_temp is None:
+            _LOGGER.warning(
+                "Temporarily skipping the self-regulation algorithm while the configured sensor for outdoor temperature is unavailable"
+            )
+            return self.target_temp
+
+        # Calculate the error factor (P)
+        error = self.target_temp - room_temp
+
+        # Calculate the sum of error (I)
+        # Discussion #384. Finally don't reset the accumulated error but smoothly reset it if the sign is inversed
+        # If the error have change its sign, reset smoothly the accumulated error
+        if error * self.accumulated_error < 0:
+            self.accumulated_error = self.accumulated_error / 2.0
+
+        self.accumulated_error += error
+
+        # Capping of the error
+        self.accumulated_error = min(
+            self.accumulated_error_threshold,
+            max(-self.accumulated_error_threshold, self.accumulated_error),
+        )
+
+        # Calculate the offset (proportionnel + intégral)
+        offset = self.kp * error + self.ki * self.accumulated_error
+
+        # Calculate the exterior offset
+        offset_ext = self.k_ext * (room_temp - external_temp)
+
+        # Capping of offset
+        total_offset = offset + offset_ext
+        total_offset = min(self.offset_max, max(-self.offset_max, total_offset))
+
+        result = round(self.target_temp + total_offset, 1)
+
+        _LOGGER.debug(
+            "PITemperatureRegulator - Error: %.2f accumulated_error: %.2f offset: %.2f offset_ext: %.2f target_tem: %.1f regulatedTemp: %.1f",
+            error,
+            self.accumulated_error,
+            offset,
+            offset_ext,
+            self.target_temp,
+            result,
+        )
+
+        return result