Electric Vehicle Motor Controller Torque Transition
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Solution Overview
Problem
Two-wheeled electric vehicles experience discontinuous changes in braking torque when transitioning from a three-phase short-circuited state to a regenerative state, leading to an unpleasant riding experience due to differences in braking torque generation in these states.
Innovation Solution
A motor controller system that includes short-circuit control, release control, and regeneration control means to manage the three-phase AC electric motor, ensuring a smooth transition by controlling regenerative current to match the braking torque generated in the short-circuited state, even when the accelerator or brake is not operated, thereby maintaining a natural riding feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If three-phase short-circuiting is performed to decelerate the motor, then braking torque is generated and speed control is achieved, but the braking torque differs from the regenerative state causing discontinuous change and poor riding feeling
Solution Approach 1:
The patent changes the parameter of regenerative current to match the braking torque characteristics of the three-phase short-circuited state. Specifically, the regenerative current is controlled to generate a braking torque that is substantially equal to the braking torque in the short-circuited state, thereby achieving smooth transition between states and eliminating discontinuous changes in braking torque.
2Use of energy by moving object
If regenerative braking is implemented to recharge the battery, then energy utilization efficiency is improved, but the braking torque differs from the short-circuited state causing discontinuous change
Solution Approach 1:
The patent adjusts the regenerative current parameter to control the braking torque generated during regenerative braking. By setting the regenerative current such that the resulting braking torque matches the braking torque of the three-phase short-circuited state, the system achieves both energy recovery and smooth riding experience without discontinuous torque changes.
Solution Approach 2:
The patent ensures continuous and smooth braking action by making the braking torque in the regenerative state substantially equal to the braking torque in the short-circuited state. This continuity eliminates abrupt changes in braking force, providing a natural and comfortable riding experience while maintaining energy recovery functionality.
3Loss of energy
If the three-phase short circuit is released and regeneration operation is started, then battery charging is achieved, but the transition causes discontinuous braking torque change giving rider a feeling of disorder
Solution Approach 1:
The patent controls the regenerative current parameter during the transition from short-circuited state to regenerative state, ensuring that the braking torque remains substantially constant. This parameter control eliminates discontinuous changes in braking torque that would otherwise occur during state transition, providing a smooth and natural riding experience while enabling battery charging.
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
The system reduces the discontinuity in braking torque, enhancing the riding experience by ensuring the regenerative braking torque matches the short-circuited state torque, providing a consistent and natural braking sensation.
Implementation Method 1
a three-phase AC electric motor 5 arranged to generate a driving force, generated by a three-phase AC electric motor, is transmitted to a drive wheel
Implementation Method 2
When the three-circuit short-circuiting is executed, the energy of rotation is thermally consumed within the electric motor and a braking torque that decelerates the rotation of the electric motor is generated
Implementation Method 3
a regeneration operation of supplying a regenerative current, generated by the electric motor, to the battery
Data Source
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AI summary
A two-wheeled electric vehicle includes a battery, a three-phase AC electric motor, a motor controller, an accelerator operator, and an accelerator operation detection means. The electric motor is arranged to generate a driving force to be transmitted to a drive wheel when a current is supplied from the battery and to generate a prescribed braking torque when coils of three phases are short-circuited. The motor controller includes a short-circuit control means for putting the electric motor in a short-circuited state in response to meeting of a short-circuiting condition, a release control means for releasing the short-circuited state in response to meeting of a release condition when the electric motor is in the short-circuited state, and a regeneration control means for executing a regeneration operation of supplying a regenerative current, generated by the electric motor, to the battery when the operation amount of the accelerator operator is zero. When the short-circuited state is released by the release control means, the regeneration control means controls the regenerative current so that the electric motor generates a braking torque equivalent to that in the three-phase short-circuited state.