Electric Motor Driving System Phase Control for Power Allocation
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Solution Overview
Problem
Existing electric motor driving systems with dual power supply-dual inverter systems face challenges in precisely controlling electric power allocation between inverters, leading to potential poor state of charge and battery degradation, especially when voltage amplitude is fixed at a maximum value, and fail to achieve effective electric power transportation and allocation during rectangular voltage wave control.
Innovation Solution
The system incorporates a control unit with first and second inverter control circuits that include an electric power controller to adjust the phase of voltage instructions, allowing for precise allocation of electric power between the pair of inverters based on a target allocation ratio or amount, even when the voltage amplitude is fixed, thereby maintaining a prescribed torque and preventing battery degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voltage amplitude is fixed at maximum value in rectangular voltage wave control, then torque output is maximized, but electric power transportation and allocation between dual power supplies cannot be achieved
Solution Approach 1:
The patent changes the control parameter from voltage amplitude to voltage phase. By adjusting the phase angle of the rectangular voltage wave while keeping amplitude at maximum, the system achieves both maximum torque output and controllable electric power allocation between dual power supplies. The phase angle becomes the new control variable that determines power distribution ratio.
2Reliability
If dual power supply-dual inverter system is used, then system redundancy and reliability are improved, but control complexity increases significantly
Solution Approach 1:
The patent makes the voltage phase control mechanism serve multiple functions simultaneously: it controls both the torque output and the electric power allocation ratio between dual power supplies. This multi-functionality reduces the need for separate control mechanisms, thereby simplifying the overall control system despite the dual power supply configuration.
Solution Approach 2:
The patent implements feedback control by detecting actual electric power allocation ratio and comparing it with the target ratio determined by phase angle. The system adjusts the voltage phase based on feedback to maintain accurate power distribution, which simplifies control by using a single unified feedback loop rather than multiple independent control systems.
3Ease of operation
If electric power allocation is not precisely controlled, then system operation is simpler, but state of charge imbalance and battery degradation occur
Solution Approach 1:
The patent enables the dual power supply system to self-regulate power allocation through phase angle control. The system automatically distributes power between power supplies according to their state of charge and capacity by adjusting the voltage phase, eliminating the need for complex external management while preventing battery degradation through balanced operation.
Data Source
AI summary
An electric motor driving system controls driving of an electric motor having windings of two or more phases each having open ends by using a pair of inverters. A control unit includes a first inverter control circuit that generates a first voltage instruction output to the first inverter based on a torque instruction and a second inverter control circuit that generates a second voltage instruction output to the second inverter based on the torque instruction. At least one of the inverter control circuits includes an electric power controller that controls allocation of electrical power supplied from a pair of power supplies to the pair of inverters, respectively, by either advancing or delaying an angle of a phase of each of vectors of voltage instructions in accordance with the target electric power instruction during execution of torque feedback control.