Karthik Kandasamy

Inter-module SoC balancing control for CHB based BESS using multi-dimensional modulation

State of Charge (SoC) imbalance between battery modules is unavoidable in high capacity Battery Energy Storage Systems (BESS). This paper investigates a module level SoC balancing control in cascaded H-bridge inverter (CHB) based BESS using multi-dimensional modulation technique. Multi-dimensional modulation is a generalized modulation strategy for cascaded H-bridge inverters. With the proposed control strategy, SoC can be equalized between the battery modules in a phase leg of CHB. The performance of the proposed control strategy under faulty cell operation is also studied. The multi-dimensional modulation strategy and the SoC balancing control are explained and the simulation results are given in this paper.

Online junction temperature estimation of IGBT modules for Space Vector Modulation based inverter system

This paper presents a junction temperature estimation model for space vector modulated IGBT inverter system for a real time implementation. Advances in power electronics, control systems, motor drives, and electrical machines helped in developing new technologies of Variable speed constant frequency (VSCF) system for more aircraft application. It is estimated that about 21% of the faults in the variable speed drive system are due to failure of power devices, Most of the inverters use insulated gate bipolar transistor so these applications require well designed thermal management systems to ensure the protection of IGBTs from thermal runaway. Therefore estimating the junction temperature has become essential to predict the fault and to assist in IGBT heath monitoring system. The proposed junction temperature estimation method is based on the power loss approach. Electro-thermal models for the commonly used Space Vector Modulation (SVM) techniques namely the alternate SVM and the Null V0V7 SVM are developed. The efficacy of the proposed junction temperature estimation model is verified using the measured junction temperature from the experimental setup.

Online electro-thermal model for real time junction temperature estimation for insulated gate bipolar transistor (IGBT)

This paper proposes an online dynamic electro-thermal model to compute the junction temperature of an IGBT under real time operating conditions. The proposed computational model is based on transient thermal capacitance and power loss calculations. Insulated Gate Bipolar Junction Transistor is popularly used in mission safety critical applications such as aerospace. Usually mission critical application requires well-designed thermal management to ensure the safety of power devices from thermal runaway. Hence, real time estimation of the junction temperature has become more important to develop health monitoring model as well to predict the lifetime of power converter system. In order to analyze the accuracies of the junction temperature estimation method, the results from the proposed dynamic electro thermal model is compared with the experimental results (measured junction temperature) obtained from the laboratory test rig.