Six-Phase EV Motor Charging Through Direct Grid Interface
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Solution Overview
Problem
Existing electric vehicles require additional hardware for charging, increasing cost and weight, and there is a need for more efficient techniques to recharge their energy storage systems.
Innovation Solution
A six-phase motor system is used, configured in two three-phase stages, allowing synchronization with a three-phase power grid for bidirectional charging, eliminating the need for additional hardware and enabling energy storage and power conditioning applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional hardware (rectifiers, converters, protection circuits) is used to charge the DC power source from the power grid, then the charging function is achieved, but the cost and weight of the electric vehicle increase
Solution Approach 1:
The patent combines the charging function with the existing AC electric motor by utilizing its multi-phase structure. The motor's phases are reconfigured to act as a generator during regenerative braking and as a charger during grid charging, merging two functions into one component and eliminating the need for separate charging hardware.
Solution Approach 2:
The AC electric motor is designed to perform multiple functions: propulsion during normal operation, energy generation during regenerative braking, and battery charging when connected to the power grid. This multi-functionality eliminates the need for dedicated charging hardware, reducing both weight and cost.
2Reliability
If additional hardware (rectifiers, converters, protection circuits) is used to charge the DC power source from the power grid, then the charging function is achieved, but the cost of the electric vehicle increases
Solution Approach 1:
The charging function is merged with the existing AC electric motor system. By reconfiguring the motor's multi-phase windings to operate in generator mode and directly interface with the DC battery through the existing inverter, the system eliminates the need for separate rectifiers, converters, and protection circuits, thereby reducing manufacturing cost.
Solution Approach 2:
The AC electric motor serves as a universal component that can function as a propulsion motor, a generator for regenerative braking, and a charger for battery replenishment from the power grid. This multi-functionality reduces the total component count and associated manufacturing costs.
3Adaptability or versatility
If the multi-phase machine is operated at grid frequency and switched to the electric grid, then direct grid interface is achieved, but control complexity increases
Solution Approach 1:
The controller dynamically reconfigures the connections of the multi-phase machine windings based on operating conditions. During grid charging, the phases are connected in a star configuration and operated at grid frequency; during regenerative braking, the configuration changes to enable generator mode. This dynamic reconfiguration allows adaptability while managing control complexity through a unified control strategy.
Solution Approach 2:
The system changes operating parameters such as frequency, voltage, and phase configuration based on the desired function. When interfacing with the grid, the machine operates at grid frequency (50/60 Hz) with appropriate voltage matching. The controller adjusts these parameters dynamically to enable direct grid interface without requiring complex additional hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces electrical emissions, enhances safety, and provides cost savings and weight reductions by allowing the electric vehicle to interface directly with the power grid for charging and energy storage, while maintaining versatility across grid frequencies and voltages.
Implementation Method 1
the second set of phases in the multi-phase machine generates energy via electrical coupling to the first set of phases in the multi-phase machine
Data Source
AI summary
A method and system for bidirectional charging in an electric vehicle include controlling a multi-phase machine in the electric vehicle. In response to determining that a direction of energy flow is from an electric grid to the electric vehicle, the method and system include operating a first set of phases in the multi-phase machine at a grid frequency of the electric grid and connecting the first set of phases in the multi-phase machine to the electric grid. In response to connecting the first set of phases in the multi-phase machine to the electric grid, the method and system include operating a second set of phases in the multi-phase machine, where the second set of phases in the multi-phase machine generates energy via electrical coupling to the first set of phases in the multi-phase machine. The method and system also include providing the energy generated by the second set of phases in the multi-phase machine to charge an energy source of the electric vehicle.