Core loss estimation of filter inductors is critical for modelling and optimising high-frequency, highefficiency and high-density Pulse Width Modulation (PWM) power electronics converters. However, data provided by inductor core manufacturers is insufficient for core loss estimation in PWM converters, particularly in the case of customized gapped inductors. This paper presents a whole process of characterising and estimating the core loss of a customised high-current gapped inductor for PWM converters. To excite the inductor for the B-H loop measurement, a test circuit formed by a half-bridge structure is proposed, which has the ability to compensate the asymmetric rectangular voltage on the inductor caused by the device voltage drops. To overcome the other challenges raised by high excitation current, a discontinuous test procedure, Triple Pulse Test (TPT), is applied to reduce the requirements of the high-current test setup (thermal stress, current-time stress for current probes, capacity of dc sources, etc.). For practical purposes, a user-friendly loss map approach is proposed involving only time-domain and electrical variables to replace magnetic variables to enable straightforward loss mapping process and core loss calculations. Presented experimental results show consistency between the estimated inductor loss and measured values. Overall, the proposed testing approach can be easily implemented on the user's side to develop a loss map of a given inductor. The established core loss map enables the users to accurately and rapidly estimate the core loss of a tested inductor for given PWM waveforms.
Along the advances of wide-bandgap power devices, the pulse width modulation (PWM) converters are developing towards higher switching frequencies in recent years. Accurate estimation of the high-frequency power losses of magnetic components, the core loss in particular, has been a challenge for PWM converters. While the conventional approaches based on Steinmetz Equation lose the accuracy in PWM excitations, the "loss map" approach has been proposed recently as a practical method to accurately estimate the inductor core loss. To calculate the core loss, the inputs of the loss map need to be retrieved from the steady-state inductor voltage/current waveforms. As a supplement to the loss map approach, this work proposes an analytical method to rapidly generate the inputs (inductor operating space) for the loss map to replace the efforts in building simulation models and experimental rigs. The proposed approach relies on the operation and modulation principles of PWM converters and enables computerized calculation of the operating space and the inductor core loss. The proposed approach is developed for both 2-level and 3-level converters and validated by experiments. The results reveal that a 3-level converter running the same inductor generates less than half the core loss compared to a 2-level converter, when the maximum current ripple is kept equivalent. The proposed approach is based on the operation principles of the converter topology and therefore can be applied generally regardless of the core material or the design of the inductor, as long as the loss map of the inductor is pre-produced.
This paper presents an optimal carrier-based voltage balancing scheme for three-phase, three-level converters. The proposed scheme utilizes two available degrees of freedom, i.e. Zero-sequence Signal Injection (ZSI) and Virtual Zero-level Modulation (VZM), to eliminate the low-frequency neutral point voltage oscillation. It is universally effective over the full power factor and modulation index range and easy to implement in digital controllers. The hybrid algorithm combines the merits of both approaches, which offers the optimal performance regarding controllability, switching device power losses and output harmonics. The main drawbacks of VZM, i.e. the increased switching loss and high-frequency harmonics due to additional switching transitions, have been minimized in the proposed scheme. The performance of the proposed scheme is evaluated through simulation and experiment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.