Electric Machine Converter Topology for Integrated External Charging
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Solution Overview
Problem
Existing electrical machines, particularly in vehicles, require efficient and cost-effective methods for charging energy storage devices externally, while maintaining high efficiency and reducing complexity in design and operation.
Innovation Solution
An electric machine unit with a converter that includes half-bridges for each phase connection, AC and DC switches for isolation and connection to external voltage sources, allowing galvanic isolation and efficient energy transfer and charging through transformer-like operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate charging device is integrated into the electric machine unit, then external charging capability is improved, but device complexity increases
Solution Approach 1:
The electric machine unit is designed to perform multiple functions: it can operate as a motor, generator, and simultaneously serve as a charging device. The converter unit enables bidirectional energy flow, allowing the system to charge the energy storage device both through regenerative braking and external AC/DC charging connections, eliminating the need for separate dedicated charging hardware
Solution Approach 2:
The charging device is merged with the existing converter unit of the electric machine. The converter unit, which already exists for motor control and regenerative braking, is extended with AC and DC switching circuits to provide external charging functionality. This integration combines what would traditionally be separate systems into a unified structure
2Adaptability or versatility
If additional charging components are added to the converter, then external charging capability is improved, but manufacturing cost increases
Solution Approach 1:
Existing converter components are made multi-functional to reduce the need for additional parts. The half-bridge circuits and switching elements already present in the converter are configured to handle both motor control and external charging operations, maximizing the utilization of existing components and minimizing additional manufacturing costs
Solution Approach 2:
The AC and DC charging circuits are merged with the existing converter architecture rather than being added as completely separate systems. This allows shared use of common components such as control circuits, housing, mounting structures, and parts of the power electronic switches, thereby reducing overall manufacturing costs
3Loss of energy
If the electric machine is used for regenerative braking, then energy recovery is improved, but the need for separate charging methods is reduced
Solution Approach 1:
The system maintains multiple charging pathways: regenerative braking through the generator function, external AC charging through the AC switching circuit, and external DC charging through the DC switching circuit. This multi-functionality ensures that energy recovery via regenerative braking is complemented by alternative charging methods, providing versatility in different operating scenarios
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
Enables efficient energy conversion and charging with reduced complexity, eliminating the need for additional components and mechanical interlocking, while enhancing power quality and grid stability.
Implementation Method 1
In electrical machines, in particular those used as motors and/or generators
Implementation Method 2
inverters (power converters) are used to rectify the alternating current generated or to alternate the direct current present
Data Source
AI summary
An electric machine unit has an electric machine with two phase groups of at least one phase each and having a power converter, the power converter having two half-bridge groups of at least one half-bridge in each case, each phase group being assigned one half-bridge group, so that one half-bridge is provided per phase connection of the electrical machine. The power converter has DC voltage terminals which are configured for connection to an energy storage, the phase terminals of a first phase group each being connected via an AC switch to the respectively associated half-bridge of a first half-bridge group, the phase terminals of a second phase group each being connected to the respectively associated half-bridge of a second half-bridge group, DC-voltage-side terminals of the half-bridges of the second half-bridge group each being connected to the DC terminals via a DC switch.