Lebing Jin

A novel inverter topology for compact EV and HEV drive systems

This paper describes a new modular inverter topology suitable for compact drive systems in electric road vehicles. The topology is based on dc-side cascading of three-phase two-level inverter bridges, each feeding a set of three-phase windings of a motor. This topology is compared by calculation to the known modular high-frequency (MHF) converter, and is found to have similar losses and semiconductor expenditure requirements. Simulations verify the dynamic and static properties of the converter in a realistic application.

Machine design considerations for an MHF/SPB-converter based electric drive

This paper identifies suitable phase/slot/pole combinations for fractional-slot concentrated winding (FSCW) permanent-magnet machines when forming an integrated electric drive together with a modular high frequency (MHF) converter or a stacked polyphase bridge (SPB) converter.

Control and modulation of the stacked polyphase bridges inverter

In order to meet the requirements of future electric vehicle (EV) drive systems, new converter topologies are required. The stacked polyphase bridges (SPB) inverter is a new topology which is well adapted to the needs for future EVs [1]. In addition to low power losses, the SPB inverter also has fault tolerance ability and good dynamic behavior. This paper presents a further analysis of the control and modulation concept of the SPB inverter. Simulation results are used to verify the analysis conclusions.

DC-Link Stability Analysis and Controller Design for the Stacked Polyphase Bridges Converter

The stacked polyphase bridges (SPB) converter consists of several submodules that all are connected in series to a voltage source. The total dc-link voltage should split in a balanced way among the submodules. This does not always occur inherently. This paper presents an analysis of the capacitor voltage stability for the SPB converter. From the analysis, criteria for stability are derived and three alternatives of a suitable balancing controller are designed. The proposed controller alternatives and their associated stability properties are verified on an experimental setup and by simulation.

Evaluation of a multiphase drive system in EV and HEV applications

Multiphase machine drive systems have been applied in many electric propulsion fields such as aerospace and electric vehicle applications. With the development of SiC semiconductors, its superior characteristic makes compact multiphase converters possible. Moreover, by using a single chip in each switch, problems caused by an uneven current split between paralleled devices can be avoided. This paper presents a performance evaluation for a 50 kW multiphase EV/HEV drive system with 12 kV SiC MOSFETs. Power loss calculation, cost comparison and system simulation are provided to illustrate the feasibility of the proposed concept.

Modulation and Power Losses of a Stacked Polyphase Bridges Converter

This paper presents and analyzes the modulation and power losses of a stacked polyphase bridge (SPB) converter—a modular topology potentially allowing increased compactness and fault tolerance for automotive drive systems. In particular, an analysis of the impact of modulation on the harmonic content of the dc link current of the converter is made. Due to the possibility of using higher switching frequency devices, the current ripple of the SPB converter can be smaller than that of the two-level three-phase converter with the same dc link capacitor. However, higher switching frequency will result in higher switching losses per fundamental period. Therefore, this paper also investigates the reduction in the dc link ripple current achieved by interleaving the modulation among the different converter submodules. The amount of reduction can be predicted using an analytical model whose results are demonstrated to be in good agreement with the results from the corresponding simulations and an experimental setup. Furthermore, based on the experimentally verified analysis, the SPB converter in a typical automotive drive system is discussed and compared with a conventional two-level three-phase converter.

Analysis of power losses in power MOSFET based stacked polyphase bridges converters

The ability to accurately predict power semiconductor losses is essential for converter design and can provide a reference for thermal management. Based on a stacked polyphase bridges converter, a simplified but accurate loss model is used in this paper to calculate the power losses of power MOSFETs and experimentally verified. A special focus of the analysis is the ringing loss calculation since it is inevitable in the switching process of power MOSFETs. In addition, this paper presents a comparison of power losses between Si MOSFET and GaN FET based converters by using the analytical model.

Analysis of the dc-link stability for the stacked polyphase bridges converter

This paper presents an analysis of the capacitor voltage stability for a stacked polyphase bridges (SPB) type converter. The SPB converter comprises of several submodules which are connected in series. Therefore, stability of the dc-link voltage is very important to investigate. From the analysis, a corresponding controller and an analytical expression for stability are derived. The proposed controller and the associated stability condition are verified in a simulation environment and on a small experimental setup.