Wound Rotor Synchronous Motor Charging System
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Solution Overview
Problem
The increasing weight, volume, and cost of eco-friendly vehicles due to the on-vehicle charging circuits required for battery charging in electric vehicles pose a significant challenge, as these circuits often rely on bulky magnetic transformers and complex control systems.
Innovation Solution
A charging system utilizing a wound rotor synchronous motor, which includes an inverter, stator coils, a field coil, and a controller to manage the charging process, allowing for selective insulation between the battery and field coil, and controlling the transfer of electricity from the grid to the stator coils for efficient battery charging, thereby eliminating the need for a separate on-vehicle charging circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate on-vehicle charging circuit with high-frequency transformer is implemented, then battery charging capability is provided, but vehicle weight and volume increase
Solution Approach 1:
The patent merges the charging circuit functionality with the existing motor structure by using the motor's field coil as part of the charging system. The high-frequency transformer and charging circuit are integrated into the motor assembly, eliminating the need for separate charging components and reducing overall vehicle weight while maintaining battery charging capability.
2Reliability
If a high-frequency transformer is used in the charging circuit, then battery charging is enabled, but the charging circuit volume increases
Solution Approach 1:
The patent implements nesting by placing the high-frequency transformer and charging circuit components within the motor's existing structural space. The transformer is positioned to utilize the motor's internal volume, and the charging circuit is integrated into the motor assembly, effectively hiding the charging components within the motor structure and reducing overall vehicle volume.
3Reliability
If a separate on-vehicle charging circuit is added, then battery charging function is provided, but manufacturing cost increases
Solution Approach 1:
The patent makes the motor structure multi-functional by enabling it to serve both as a propulsion motor and as part of the charging system. The field coil and rotor structure are designed to function during both motor operation and battery charging modes, eliminating the need for dedicated charging components and reducing manufacturing costs through component sharing.
4Ease of operation
If the battery is directly connected to the field coil for charging, then charging simplicity is achieved, but charging current control precision is reduced
Solution Approach 1:
The patent implements a feedback control system with a controller that monitors the charging current flowing through the field coil and adjusts the inverter's output accordingly. The controller receives feedback signals about the actual charging current and modifies the inverter's switching patterns to maintain precise current control, ensuring accurate charging while keeping the system relatively simple.
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 the weight, volume, and cost of the vehicle while enhancing battery charging capacity and efficiency, allowing for high-efficiency charging and expanded charge capacity without additional circuits, particularly during fast charging.
Implementation Method 1
a field coil configured to form a mutual inductance with the stator coils, the field coil being installed in a rotor to form a magnetic flux using a direct current output of the battery and being connected to a grid when the battery is being charged
Data Source
AI summary
Disclosed herein is a charging system using a wound rotor synchronous motor, capable of increasing a battery charging capacity while reducing the volume, weight, and/or cost of a vehicle increased due to an on-vehicle charging circuit. The charging system includes an inverter converting a DC output of a battery into a plurality of AC signals having different phases, a wound rotor synchronous motor having a plurality of stator coils, to which the AC signals having different phases are respectively input, and a field coil forming a mutual inductance with the stator coils, the field coil being installed in a rotor to form a magnetic flux using the DC output of the battery, and a controller allowing the battery and the field coil to be insulated from each other in a charge mode in which electricity from a grid is applied to the field coil of the wound rotor synchronous motor.