Integration of Six-Phase EV Drivetrains Into Battery Charging Process With Direct Grid Connection

Abstract

The paper proposes two novel topologies for integrated battery charging of electric vehicles. The integration is functional and manifests through re-utilization of existing propulsion drivetrain components, primarily a six-phase inverter and a six-phase machine, to serve as components of a fast (three-phase) charging system. An important feature of the proposed charging systems is that they are with direct grid connection, thus nonisolated from the mains. Torque is not produced in machines during the charging process. The paper provides a comprehensive evaluation of the novel systems, together with an existing topology. Various aspects of the considered chargers are detailed and elaborated, including current balancing, interleaving modulation strategy, and influence of rotor field pulsation on control and overall performance. A control strategy is proposed and the theory and control scheme are verified by experiments. Index Terms-Battery chargers, electric vehicles, integrated onboard chargers, multiphase machines. I. INTRODUCTION V ARIOUS concepts for battery charging of EVs have been proposed over the years, including fast dc (off-board) charging (Fig. 1(a)), battery swapping, inductive (wireless) charging, conventional on-board (Fig. 1(b)) and integrated onboard charging (Fig. 1(c)) [1]. The latter is a process in which already existing power electronic components, which exist onboard an EV and that are mandatory for vehicle propulsion, are re-utilized for charging. As fewer new elements are required for the charging process, the vehicle cost, weight and required space are significantly reduced. These advantages have in the last five years put integrated chargers under extensive research focus of both academic community and industry [2]. There are two main types of integrated chargers: those that take supply from a single-phase voltage source (slow) [3] and those that are attached to three-phase mains (fast) [4]. A distinct advantage of the three-phase over the single-phase integrated chargers is a much faster charging process. On the other hand, if a three-phase machine is integrated into three-phase charging process, three-phase currents flow through its windings,

Finite Control Set Model Predictive Control of Six-Phase Asymmetrical Machines—An Overview

“…VV1 (36,53) VV2 (52,38) VV3 (54,20) VV4 (22,50) VV5 (18,30) VV6 (26,19) VV7 (27,10) VV8 (11,25) VV9 (9,43) VV10 (41,13) VV11 (45,33) VV12 ( To improve the performance of a six-phase PMSM drive at low speeds, a VV-PCC strategy based on an extended set of twenty-five virtual vectors (EVV-PCC) was proposed in Reference [112]. The extra twelve virtual vectors {v v13 , ..., v v24 } shown in Figure 5 have an amplitude of 0.345 • U dc and are created by the combination of one medium-large and one small vector, with the same phase in the α-β subspace (Figure 2), during a sampling period with duty cycles given by:…”

“…Multimotor drives proposed in the 2000s is another application that takes advantage of the additional degrees of freedom, where a single n-phase VSI is able to drive independently up to (n − 1) /2 machines if n is odd or up to (n − 2) /2 machines if n is even, either connected in series or in parallel [10,11]. More recently, the additional degrees of freedom of multiphase machines are being used to provide: balancing of the dc-link capacitors of series-connected VSIs on the machine side [12]; unequal power sharing [13,14]; full-load test methods [15,16]; integrated battery charging for electric vehicles [17][18][19]; dynamic braking for non-regenerative electric drives [20,21];…”

A Review of on-Board Integrated Electric Vehicles Charger and a New Single-Phase Integrated Charger

“…Because of the motor windings reconfiguration, it is equal to three-phase windings and three IGBT legs during the charging mode. The similar theory is used to a threephase integrated charger based on six-phase motor in [45], [46], as shown in Fig. 12.…”

Vehicle Electrification: Technologies, Challenges, and a Global Perspective for Smart Grids

“…Slow [207] and fast [208] battery charging operations concerning integrated battery chargers with five-phase, sixphase, and nine-phase motors were analyzed in the same year by the same authors, and galvanic isolation was considered for six-phase motors the next year [209]. Further reading concerning multi-phase motors and integrated battery chargers for these can be found in [210][211][212].…”