Dual-Motor EV Inverter Control for Beat Suppression
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Solution Overview
Problem
The challenge is to suppress the occurrence of beats in electrified vehicles while minimizing manufacturing costs, which are increased by varying the hardware configurations of in-wheel motors.
Innovation Solution
Implementing a control device that sets specific current effective value and advance value commands in a dq coordinate system to manage torque and rotational speed differences between motors, thereby controlling torque variations to prevent beats without altering hardware configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the hardware configurations of in-wheel motors are varied to suppress beats, then the beat suppression effect is improved, but the manufacturing costs increase
Solution Approach 1:
The patent changes the control parameters (current effective value command and current advance value command) of the in-wheel motors instead of changing hardware configurations. By adjusting these parameters, the torque variation difference between motors is controlled to be equal to or larger than a predetermined value, which suppresses beats while using identical hardware configurations for all motors, thereby reducing manufacturing costs.
Solution Approach 2:
The patent replaces the mechanical approach of varying hardware configurations with an electrical control approach. The control device adjusts the current vectors in the dq coordinate system to create torque variation differences between motors, substituting mechanical differentiation with electrical parameter control. This eliminates the need for different hardware configurations while achieving beat suppression.
2Object-affected harmful factors
If the torque variation difference between motors is increased to suppress beats, then the beat suppression effect is improved, but the torque control precision may deteriorate
Solution Approach 1:
The patent dynamically adjusts the current effective value command and current advance value command based on operating conditions. The control device calculates appropriate parameter values that satisfy both the beat suppression requirement (torque variation difference ≥ predetermined value) and the torque control precision requirement. This dynamic adjustment allows the system to adapt to different operating states while maintaining both beat suppression and control precision.
Solution Approach 2:
The patent carefully selects and adjusts control parameters within specific ranges to achieve multiple objectives. By controlling the torque variation difference to be equal to or larger than a predetermined value while managing the torque commands appropriately, the system achieves beat suppression without compromising torque control precision. The parameter changes are constrained to satisfy multiple performance requirements simultaneously.
Data Source
AI summary
An electrified vehicle includes first and second motors, first and second inverters for driving the first and second motors, respectively, and a control device configured to control the first and second inverters by setting first and second current effective value commands, and first and second current advance value commands of first and second current vectors in a dq coordinate system including a d-axis and a q-axis as coordinate axes based on first and second torque commands for the first and second motors. The control device is configured to set the first and second current effective value commands and the first and second current advance value commands to control a torque variation difference to be a predetermined torque variation difference or larger when a torque difference is a predetermined torque difference or smaller and a rotational speed difference is a predetermined rotational speed difference or smaller.