Switchable Multi-Stage Inverter for Double-Rotor EV Drives
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Solution Overview
Problem
Current two-stage inverters dominate electric vehicle drive systems, while three-stage or multi-stage inverters, offering advantages like lower harmonics and higher voltage handling, are not used due to perceived insufficient benefits and additional costs in automotive applications.
Innovation Solution
A controllable three- or multi-stage inverter system with an operating mode setting device that adjusts between two-stage and three-stage operations based on efficiency, combined with a solid double rotor electric machine, to minimize losses and improve efficiency without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If three-stage or multi-stage inverters are used, then voltage handling capability and harmonic performance are improved, but device complexity and cost increase
Solution Approach 1:
The inverter is designed with dynamically switchable circuit configurations that can transition between two-stage and three-stage topologies. Switching elements are arranged to enable reconfiguration of the power conversion circuit, allowing the system to adapt its stage configuration based on operational requirements, thus providing high voltage handling capability only when needed while reducing complexity during normal operation
Solution Approach 2:
The system changes its operational parameters by switching between different inverter stage configurations. The number of voltage levels and circuit topology are changed dynamically based on load conditions and efficiency requirements, allowing the inverter to optimize its performance characteristics without being permanently fixed in a complex multi-stage configuration
2Loss of energy
If three-stage or multi-stage inverters are used, then efficiency at high voltage is improved, but manufacturing cost increases
Solution Approach 1:
The inverter employs dynamically reconfigurable circuit elements that can switch between two-stage and three-stage configurations. This allows the system to achieve high efficiency through three-stage operation only when operating conditions warrant the additional performance benefits, while maintaining cost-effectiveness by defaulting to the simpler two-stage configuration for standard applications
Solution Approach 2:
The system optimizes efficiency by changing its operational configuration based on detected operating parameters such as load level and efficiency requirements. At low load conditions where three-stage operation provides significant efficiency improvements, the system switches to three-stage configuration, thereby reducing energy losses without incurring the full manufacturing cost of a permanent multi-stage design
3Device complexity
If inverter operates in two-stage mode, then device simplicity is maintained, but losses increase particularly at low loads
Solution Approach 1:
The inverter system dynamically transitions between two-stage and three-stage configurations based on real-time monitoring of operational conditions. When operating at low load levels where two-stage mode produces excessive losses, the system automatically reconfigures to three-stage mode to minimize energy waste, while maintaining structural simplicity by defaulting to two-stage operation during normal conditions
Solution Approach 2:
The system changes its operational parameters by switching inverter configuration in response to detected efficiency requirements. At low load conditions, the system transitions to three-stage operation to reduce losses, thereby optimizing energy efficiency without permanently increasing device complexity or manufacturing cost
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
Significantly reduces losses in the electric drive system, particularly at low loads, by optimizing inverter operation and using a solid double rotor design, enhancing overall efficiency and cost-effectiveness.
Implementation Method 1
Two-stage inverters convert the direct current from a direct current source into an alternating current with two voltage levels
Implementation Method 2
electric machines, such as synchronous or asynchronous machines, which are powered by a multiphase alternating current
Data Source
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AI summary
The present invention relates to an electrical drive system for or in a motor-vehicle, having at least one multi-phase electric machine, which has a double rotor, wherein the double rotor is made from flux-guiding material made of solid material, with a three-stage or multi-stage inverter circuit for driving the electric machine, which has: a controllable three-stage or multi-stage inverter coupled to the electric machine on the output side, which is designed to supply the electric machine with an AC voltage, and an operating mode setting device, which is designed to operate the inverter as a function of at least one parameter influencing the overall efficiency of the electrical drive system, selectively in a three-stage or multi-stage operation or in a two-stage operation.