US Patent 11874338 Motorless power electronic test device

A “motorless” power electronic test device for testing adjustable speed motor drives without having to connect motors to the drive includes a bidirectional internal power converter, filtering, a charging switch for charging the capacitors of internal and external power converters, line switches for setting the test mode and operating the device, and a switch controller. The test device can be set to separately test an external power converter or an external rectifier, with the internal power converter operating in an AC-to-DC mode for testing the external power converter, and operating in a DC-to-AC mode for testing the external rectifier. The motorless test device recycles test power to reduce testing losses and carbon footprint. It is also much lighter and more convenient to handle than a full-load motor-absorber and, therefore, more amenable to deployment as a portable unit that can be readily transported to customer sites.