Motor Drive Voltage Control Minimizing System Loss
Solution Overview
Problem
Existing motor drive control systems fail to minimize overall system loss effectively, as they rely on pre-generated maps to determine target post-boost voltages, which may not optimize losses across all system devices.
Innovation Solution
A motor drive apparatus with a voltage boost circuit and a control device that calculates a target system voltage using function expressions approximating loss characteristics, allowing for selective switching between PWM and rectangular-wave voltage control modes to minimize system losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pre-generated maps are used to determine target post-boost voltages, then the control system is simple to implement, but the overall system loss cannot be minimized effectively
Solution Approach 1:
The patent changes the control parameter from fixed map-based voltage selection to dynamic voltage calculation based on loss function. The control device calculates target post-boost voltage by changing system voltage parameters to minimize overall system loss, considering voltage-dependent loss characteristics of different devices. This resolves the contradiction by allowing energy loss minimization through parameter optimization while maintaining practical implementability.
Solution Approach 2:
The patent introduces dynamic voltage control where the target post-boost voltage is not fixed but dynamically calculated based on current operating conditions. The control device continuously adjusts the system voltage to minimize loss, making the system adaptive to changing conditions. This dynamic approach resolves the contradiction between simple implementation and effective loss minimization.
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 approach enables the calculation of a target system voltage that minimizes overall system loss by accurately representing loss changes with respect to system voltage, optimizing energy efficiency across the motor drive apparatus.
Implementation Method 1
a voltage boost circuit provided between a DC power supply and the drive unit and performing voltage boost so that a system voltage which is a voltage for the drive unit is equal to or higher than a voltage of the DC power supply
Data Source
AI summary
An ECU sets target value of a system voltage based on an electric power loss of a motor generator and an inverter and controls a voltage boost converter. The ECU calculates the target value of the system voltage using a function expression generated, for each operating point of the motor generator, by approximating a loss characteristic which represents change of the electric power loss with respect to change of the system voltage, by a quadratic expression or a linear expression of the system voltage.