Conventional avionic refrigeration systems typically include a refrigeration line replaceable unit (LRU), for example, a chiller that is configured to keep items such as food and beverages cold. Such conventional avionic refrigeration systems have a number of drawbacks, largely stemming from the construction of the refrigeration LRU. As is known, conventional refrigeration LRUs include AC induction motors for operating the compressor, condenser and evaporator units. While AC induction motors are used for many applications due to their low cost and ruggedness, AC induction motors are not well suited to avionic applications due to their large size, weight and difficulty to accurately and variably control.
For example, feedback control of AC induction motors is typically accomplished using electromechanical position sensors such as Hall Effect sensors that are disposed in the motor housing. A number of wires extend from the sensor and motor housing to provide signals to a motor controller or the like. Disadvantageously, in an avionic environment, sensor wiring may be aggregated with other power, control and communication wiring in a wiring harness causing position sensor data that is communicated by the wires to be corrupted due to harness crosstalk, electromagnetic interference (EMI) or the like. Furthermore, electromechanical position sensors such as Hall Effect sensors are prone to malfunction or failure over time due to wear and tear. When such a sensor malfunctions or fails, the motor cannot be controlled and must be replaced or repaired. Moreover, in the context of a refrigeration unit, it is difficult to reliably employ a Hall Effect sensor in a compressor due to the compressor being sealed and containing refrigerant and oil. In view of the foregoing, a refrigeration system that included a refrigeration LRU which did not employ AC induction motors and which could be more accurately and variably controlled would be an important improvement in the art.