Motor Control System Minimizing Heat via Dynamic Voltage Adjustment
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Solution Overview
Problem
Permanent magnet synchronous motors in environmentally-friendly vehicles generate excessive heat due to varying input voltage from limited power sources, affecting fuel economy and cooling burdens.
Innovation Solution
A motor control system that includes a power source, converter, relay module, inverter module, and controller, which performs minimum heat-generation control by calculating and applying inverter input voltage to minimize heat generated through flux-weakening control and its suppression, using characteristic values related to currents and voltage-converting characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the power supplying device operates at limited capacity, then the vehicle can maintain compact size, but the output voltage varies causing excessive heat generation in the motor and controller
Solution Approach 1:
The patent implements dynamic voltage adjustment by varying the inverter input voltage based on motor speed and torque requirements. The controller dynamically selects operating points that minimize heat generation while meeting performance demands, transforming the static voltage limitation into a dynamic optimization problem that resolves the contradiction between compact power supply design and heat control
Solution Approach 2:
The patent changes the voltage parameter dynamically during operation. By adjusting the inverter input voltage according to the motor's operating conditions (speed, torque, flux-weakening requirements), the system optimizes the balance between power delivery and heat generation, allowing the compact power supplying device to operate efficiently across different loading conditions
2Speed
If flux-weakening control is applied to high-speed motor operation, then the motor can operate above base speed, but heat generation increases due to additional current requirements
Solution Approach 1:
The patent applies partial flux-weakening control only when necessary for high-speed operation, rather than continuously. The controller selectively activates flux-weakening mode based on speed thresholds and torque requirements, applying the minimum necessary current to achieve the desired speed while minimizing additional heat generation from the flux-weakening current
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
Reduces heat generation in the motor and inverter module, minimizing energy loss and cooling costs, thereby enhancing fuel economy and the environmental efficiency of the vehicle.
Implementation Method 1
a converter selectively configured to receive and convert the DC electricity of the power source into inverter input voltage
Implementation Method 2
an inverter module configured to receive the inverter input voltage from the converter, convert the inverter input voltage into 3-phase AC current
Implementation Method 3
a motor that generates a driving torque by using electricity from a battery
Data Source
AI summary
A system for controlling a motor of a vehicle that improves fuel economy by minimizing a sum of heat generated by the motor and heat generated by a converter, is disclosed. More specifically, a power source supplies DC electricity; a converter selectively receives and converts the DC electricity of the power source into inverter input voltage. A relay module selectively connects the power source to the converter and an inverter module receives the inverter input voltage from the converter, converts the inverter input voltage into 3-phase AC current, and supplies the 3-phase AC current to the motor. Further, a controller controls operations of the converter, the relay module, and the inverter module, to perform to minimize the inverter input voltage that is a sum of heat generated due to the flux-weakening control and heat generated due to suppression of the flux-weakening control.