Efficiency evaluation of interior permanent magnet synchronous machines using the synthetic loading technique

This paper presents the application of synthetic loading for efficiency evaluation of interior permanent magnet (IPM) synchronous machines and compares it with the standard technique of assessing efficiency and losses. Good agreement is observed between the two techniques. Synthetic loading is a technique of efficiency evaluation that eliminates the need for a mechanical load connected to the test machine. Equations for synthetic loading are developed for the IPM synchronous machine which are then used to simulate the technique using MATLAB. The synthetic loading technique is performed experimentally in the laboratory and a full description of the hardware system is provided. The minimum dc link voltage and volt-ampere requirements of the inverter used to conduct the synthetic loading test are assessed, discussed and compared with the standard efficiency test. Simulation and experimental results demonstrate that the synthetic loading technique is able to evaluate the efficiency of IPM synchronous machines.