Three-Phase Inverter Negative Torque Control for Shift Down
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Solution Overview
Problem
Existing electronic control devices for vehicles with electric continuously variable transmissions (electric CVT) face difficulties in generating a negative torque corresponding to a shift down operation, especially when the battery is not chargeable, due to the limitations of three-phase on-control methods that result in inadequate control of the regeneration torque at the motor generator.
Innovation Solution
An electronic control device is implemented with a detector for shift down operations, a determination device to assess battery chargeability, and a controller that outputs a switching signal to all upper or lower arms of the three-phase inverter for simultaneous on-control, combined with PWM control of a shutdown signal to generate the required negative torque at the motor generator, even when the battery is not chargeable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If three-phase on control is performed to generate negative torque at the motor generator, then the vehicle can reduce speed, but the regeneration torque becomes smaller and the battery cannot be charged
Solution Approach 1:
The patent applies periodic action by alternately turning on and off the upper arms and lower arms in a pulsed manner during shift down operations. Instead of maintaining continuous three-phase on control, the controller periodically switches the arms on and off, which allows the motor generator to generate negative torque for speed reduction while preventing continuous regeneration current flow to the battery. This periodic switching resolves the contradiction by enabling speed reduction without requiring the battery to be chargeable.
2Force
If all upper arms or all lower arms are turned on simultaneously for three-phase on control, then the motor generator can generate negative torque, but it is difficult to adjust or control the negative torque to match the required torque
Solution Approach 1:
The patent applies dynamics by dynamically controlling the switching state of the upper arms and lower arms based on the detected shift down operation. The controller dynamically adjusts which arms are turned on and off, and controls the duration and timing of their on-states, enabling precise adjustment of the negative torque generated by the motor generator. This dynamic control resolves the contradiction by making torque adjustability possible while maintaining negative torque generation capability.
Solution Approach 2:
The patent applies partial action by selectively turning on only certain upper arms and lower arms rather than all arms simultaneously. The controller determines the appropriate combination and timing of arm activation based on the required negative torque level, enabling fine-grained control of the torque magnitude. This partial activation approach resolves the contradiction by providing torque adjustability while still achieving the necessary negative torque for shift down operations.
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
This solution effectively generates the necessary negative torque during shift down operations without generating regeneration current, ensuring efficient vehicle speed reduction and improved energy management by mixing three-phase on and off states through PWM control, even when the battery cannot be charged.
Implementation Method 1
a three phase inverter executing an electricity conversion between the battery and the motor generator bi-directionally
Implementation Method 2
the controller controls the three phase inverter to generate the negative torque at the motor generator
Data Source
AI summary
An electronic control device on a vehicle having a shift transmission operable by a driver includes: a battery; a motor generator; and a three-phase inverter executing an electricity conversion between the battery and the motor generator bi-directionally; a detector detecting a shift down operation; an obtaining device obtaining a negative torque corresponding to the shift down operation; a determination device determining whether the battery is chargeable; and a controller controlling the three-phase inverter to generate the negative torque at the motor generator. When the detector detects the shift down operation, and the determination device determines that the battery is not chargeable, the controller outputs a switching signal to all of three upper arms or all of three lower arms to turn on simultaneously, and outputs a shutdown signal to all of three upper arms or all of three lower arms with executing a PWM control of the shutdown signal.