Coil Temperature Estimator¶

The Coil Temperature Estimator is a convection and conduction based thermal model to estimate the temperature of motor coils when they are not directly sensed. The temperature is used to derate the motor if the temperature rises into dangerous levels. The temperature limits can be adjusted, though this is not recommended. The convection coefficient should be tuned for the specific propeller used on the motor. A convection coefficient for an average sized propeller for the given motor is loaded by default. Consider changing the convection coefficient if a relatively large or small propeller is used, or if extreme performance and accuracy are required.

Arduino¶

To use the Coil Temperature Estimator in Arduino, ensure coil_temperature_estimator_client.hpp is included. This allows the creation of a CoilTemperatureEstimatorClient object. See the Message Table below for available messages. All message objects use the Short Name with a trailing underscore. All messages use the standard Get/Set/Save functions.

A minimal working example for the CoilTemperatureEstimatorClient is:

#include <iq_module_communication.hpp>

IqSerial ser(Serial2);
CoilTemperatureEstimatorClient tmp(0);

void setup() {
    ser.begin();
    // Initialize Serial (for displaying information on the terminal)
    Serial.begin(115200);
}

void loop() {
    float temperature = 0.0f;
    if(ser.get(tmp.t_coil_, temperature))
    Serial.println(temperature);
}

C++¶

To use the Coil Temperature Estimator client in C++, include coil_temperature_estimator_client.hpp. This allows the creation of a CoilTemperatureEstimator object. See the Message Table below for available messages. All message objects use the Short Name with a trailing underscore. All messages use the standard Get/Set/Save functions.

A minimal working example for the TemperatureEstimatorClient is:

Note

Interfacing with Serial looks different on different machines. Therefore, this example does not include code for interfacing with the hardware.

For more, see Full Examples

#include "generic_interface.hpp"
#include "coil_temperature_estimator_client.hpp"


void main(){
    // Make a communication interface object
    GenericInterface com;

    // Make a Temperature Estimator object with obj_id 0
    CoilTemperatureEstimatorClient temp_client(0);

    // Use the Temperature Estimator Client
    temp_client.temp_.get(com);

    // [Insert code for interfacing with hardware here]

    // temp = temp_client.temp_.get_reply();
}

Matlab¶

To use the Coil Temperature Estimator client in Matlab, all Vertiq communication code must be included in your path. This allows the creation of a CoilTemperatureEstimatorClient object. See the Message Table below for available messages. All message strings use the Short Names. All messages use the standard Get/Set/Save functions.

A minimal working example for the CoilTemperatureEstimatorClient is:

% Make a communication interface object
com = MessageInterface(’COM18’,115200);
% Make a CoilTemperatureEstimatorClient object with obj_id 0
CoilTemperatureEstimator = CoilTemperatureEstimatorClient(’com’,com);
% Use the CoilTemperatureEstimatorClient object
coilTemp = CoilTemperatureEstimator.get(’t_coil’);

Python¶

To use the Coil Temperature Estimator Client in Python, import iqmotion and create a module that has the Coil Temperature Estimator Client within its firmware. See the Message Table below for available messages. All message strings use the Short Names. All messages use the standard Get/Set/Save functions.

A minimal working example for the Temperature Estimator Client is:

import iqmotion as iq

com = iq.SerialCommunicator("/dev/ttyUSB0")
|variable_name| = iq.|module_name|(com, 0) |module_name_comment|

coil_temp = |variable_name|.get("coil_temperature_estimator", "t_coil")  # Estimated Motor Temperature
print(f"Estimated Motor Temperature: {coil_temp}")

Message Table¶

Type ID 83 | Coil Temperature Estimator

Coil Temperature Estimator¶
Sub ID	Short Name	Access	Data Type	Unit	Note
0	t_coil	get	float	\(^{\circ}C\)	This is the estimated temperature of the motor coils.
1	t_alu	get	float	\(^{\circ}C\)	This is the estimated temperature of the stator aluminum.
2	t_amb	get, set, save	float	\(^{\circ}C\)	This is the estimated temperature of the ambient air, which is usually conservative.
3	h_coil_amb_free_conv	get, set, save	float		This is the free convection heat transfer coefficient used when the motor is not spinning.
4	h_coil_stator_cond	get, set, save	float		This is the conduction heat transfer coefficient between the coils and the stator aluminum.
5	h_coil_amb_forced_conv	get	float		This is the the present calculated force heat transfer convection coefficient.
6	c_coil	get, set, save	float		This is the thermal heat capacitance/mass of the coils.
7	h_coil_amb_forced_conv_coeff	get, set, save	float		This is the forced convection coefficient calculation coefficient. h_forced_conv = h_conv_coeff * sqrt(speed)
8	otw	get, set, save	float	\(^{\circ}C\)	This is the over temperature warning. The motor begins to derate at this temperature.
9	otlo	get, set, save	float	\(^{\circ}C\)	This is the over temperature lock out. The derating of the motor ends at this temperature, where the motor is fully disabled.
10	derate	get	float		This is the amount of derating applied to motor [0, 1] where 1 is normal operation.
11	q_coil_joule	get	float	\(W\)	This is the present heating power in coils.
12	q_coil_amb_conv	get	float	\(W\)	This is the present ambient convective cooling power.
13	q_coil_stator_cond	get	float	\(W\)	This is the present stator conductive cooling power.
14	h_lam_alu	get, set, save	float	\(\frac{W}{m^2 * ^{\circ}C}\)	This is the the heat transfer coefficient from the laminations to the aluminum stator mount.
15	c_lam	get, set, save	float		This is the thermal heat capacitance of the laminations.
16	k_lam_hist_coeff	get, set, save	float	\(\frac{W}{\text{rad}/s}\)	This is the constant for calculating the iron losses as a function of speed based on the laminations, hysteresis, and eddy currents.
17	q_lam_hist	get, set, save	float	\(W\)	This is the iron loss coefficient of the stator.
18	q_lam_alu	get, set, save	float	\(W\)	This is the present heating power in stator aluminum.
19	t_lam	get, set, save	float	\(^{\circ}C\)	This is the estimated temperature of stator.