A Novel Test Setup for Arbitrary PWM Converter Excitations of Nonlinear Inductors

Abstract:
This paper presents a test setup to emulate the operation of inductors in pulse width modulated converters in continuous conduction mode. The setup allows the investigation of nonlinear inductances of ferrite material with an abrupt onset of saturation by using a current mode controlled converter. Even in case of saturation the current stays within proper boundaries. The proposed measurement circuit bases on two half-bridge configurations that use different control approaches to set the current limits and the voltage across the inductor, respectively. This enables to set the frequency, the duty cycle, the minimum and the maximum value of the inductor current independently. Advantageously, the circuit circulates reactive power through the device under test, which means that only the power loss needs to be fed to the system by a dc source. The test setup enables to study the temperature rise and the saturation behavior of nonlinear inductors.