Encoders and Transducers

A Peltier device working in cooling mode with a hot side temperature of 50 degC. In cooling mode, the Coefficient of Performance (COP) of the Peltier cell is equal to the total heat transferred through the Thermoelectric cooler (TEC) divided by the electric input power, COP = Qc/Pin.

Control the rotor speed in a permanent magnet synchronous machine (PMSM) based electrical-traction drive. A high-voltage battery feeds the FEM-Parameterized PMSM block through a controlled three-phase converter. A Rotational Friction block provides the load. The position and speed information are obtained by using a high-fidelity resolver. The PMSM controller subsystem includes a cascade control structure which has an outer speed-control loop and two inner current-control loops. During the 0.25 seconds simulation, the rotor speed demand is ramped-up from 0 to 1000 rpm.

A three-phase bridge cycloconverter. The cycloconverter consists of 36 thyristors and has the capacity to lower the frequency of the input voltage. The Control subsystem implements the cycloconverter RMS voltage control. It also provides pulse generation for the firing of the thyristors. The Visualization subsystem contains scopes that allow you to see the simulation results. The simulation time, t, is 1 second. The load increases when Load1 switches on at t = 0.75 seconds.

Model the interface between a microcontroller unit (MCU) and a physical system. Here the microcontroller's GPIO, ADC and DAC connections are used to control a DC motor and connected load with limited angle travel. Load angle measurement is via a potentiometer sensor. This measurement is calibrated by initially ramping the rotor position until the photodiode detects the zero-angle light pulse from the LED. Once calibrated the MCU commands a 0.1Hz 45 degree amplitude sinusoid.

How a flyback converter can step-up a 5V DC source into a 15V DC regulated supply. The voltage is increased by creating a time-varying voltage across a transformer primary. The transformer steps up the voltage which is then rectified back to DC by the diode. Closed-loop control over the output voltage is effected by controlling the switching frequency on the primary side.

How to model a strain gauge and measurement amplifier. The strain gauge forms one leg of a Wheatstone bridge, which is connected to a differential amplifier. A second op-amp is then used to both amplify and apply a low-pass filter to the measurement signal. The op-amps are modeled at a system level, with the user specifying parameters such as open-loop bandwidth, gain and maximum slew rate. In this circuit, the dynamics are primarily set by the low-pass filter. The op-amp bandwidth and maximum slew rate have little impact on the step response.

How fundamental thermal, mechanical and electrical components can be used to model a thermistor-controlled fan. The heat-generating device starts producing 2 watts at time zero, and then at 40 seconds this increases to 20 watts. The thermistor therefore heats up, and its resistance decreases thereby increasing the voltage across the PWM reference pins. This increases the PWM frequency which in turn increases average motor current, and the fan speeds up. The additional fan speed increases the convective cooling of the device, moderating the temperature increase of the device.