A Modular Multi-Phase Actively Controlled Resistive Load Bank with Zero-Current Switching Capability and Integrated Snubbers

Increased demand for electric vehicles has created a growing market for high-performance inverters. These new drives are capable of supplying high power at effective switching frequencies approaching MHz and modulation frequencies at several kHz for high-speed machines. To emulate realistic operating conditions for testing of these inverters, a test load must handle a demanding combination of high frequency, high power, and high voltage not frequently found in commercially available equipment. Moreover, resistive load banks are preferred, as the inverter's fast digital control loops may interact in undesirable ways with an active electronic load bank controller. This work presents an easy-to-use computer-controlled modular resistive load bank designed for testing of advanced, high-frequency inverters. After an overview of existing technologies, key system-level design choices are discussed. Next, specifics of the switch implementation are presented, followed by a description of the control system, switch signaling, and zero-current sensing. In addition, the Python-based user interface is outlined. Finally, experimental results demonstrating high-power switching, both at peak current and zero current, are shown.