A Minimalist High-Power Boost Charging Solution Integrated Into Electric Drives

The drive power and charging performance of leading electric vehicles (EVs) continue to advance, with high-performance EVs elevating their high-voltage platform ranges from below 500V to 800V and even 900V. To be compatible with existing public charging stations of lower voltage, vehicles with high-voltage platforms often equip a boost charge device. However, this boost charge device incurs additional costs, weight, and space requirements. Most mature solutions employ an additional DC-DC boost converter, which, however, results in low charging power at a high cost. Some new approaches utilize the power switching devices and motor inductance of electric drives to form a boost converter circuit, using a three-phase current in-phase control strategy for charging. This method requires external inductors to reduce charging current ripples. Alternatively, to minimize current ripple without external inductors, a two-phase parallel and one-phase series topology is used, albeit at the expense of reduced power and increased risk in torque control during charging. This paper proposes a systematically innovative integrated boost charging solution that employs a three-phase current phase-shift control algorithm. This approach does not require additional external inductors. Concurrently, an intelligent voltage regulation strategy, low-loss motor rotor design, and enhanced cooling solutions are implemented to address the heat risk associated with rotor magnets. Compared to traditional solutions, this approach offers the lowest increase in overall vehicle cost, minimal space occupation, maximum boost charging power, and the safest zero-torque output.