Motor Control Device Voltage Optimization
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Solution Overview
Problem
The existing motor control devices face significant heat generation and loss issues in switching elements due to high input voltages required for high torque operations, leading to inefficient energy use and increased thermal management challenges.
Innovation Solution
A motor control device that calculates and sets a target input voltage based on minimum power loss conditions, using a combination of rotation speed, torque, and voltage detection units to optimize the input voltage, setting either the optimum or minimum voltage as the target input voltage depending on the torque requirements, thereby reducing heat generation and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the target input voltage is set to a higher value for generating higher motor torque, then the motor torque is improved, but the loss in the switching element of the inverter becomes large and heat generation becomes large
Solution Approach 1:
The patent applies dynamics by making the target input voltage adjustable rather than fixed. The control device dynamically changes the target input voltage based on operating conditions (motor torque requirements). When high torque is needed, it allows higher voltage; when low torque suffices, it reduces the voltage. This dynamic adjustment resolves the contradiction by optimizing the voltage level for each specific operating condition rather than maintaining a consistently high voltage that causes excessive losses during low-torque operation
Solution Approach 2:
The patent changes the parameter of target input voltage based on motor torque requirements. The control device calculates the actual motor torque and adjusts the target input voltage accordingly - using higher voltages only when high torque is required and lower voltages when sufficient torque can be achieved with reduced voltage. This parameter change strategy resolves the contradiction by matching voltage levels to actual torque needs, minimizing unnecessary energy losses in switching elements during low-torque operation
2Force
If the target input voltage is set to a higher value for generating higher motor torque, then the motor torque is improved, but the heat generation becomes large
Solution Approach 1:
The control device dynamically adjusts the target input voltage based on actual motor torque requirements. During low-torque operation, it reduces the voltage to minimize heat generation in switching elements. During high-torque demand, it allows higher voltage to achieve the required torque. This dynamic voltage adjustment resolves the contradiction between torque output and heat generation by adapting voltage levels to match actual operational needs
Solution Approach 2:
The patent changes the target input voltage parameter according to motor torque conditions. The control device monitors motor torque and adjusts the voltage parameter accordingly - using lower voltages when sufficient torque can be achieved with reduced power loss and heat generation, and higher voltages only when high torque is genuinely required. This parameter adaptation resolves the contradiction by optimizing the thermal performance while maintaining torque capability
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 effectively suppresses heat generation in switching elements, improves energy efficiency, and ensures efficient motor operation by minimizing power losses across the inverter, motor, and converter components.
Implementation Method 1
performs pulse width modulation (PWM) control for a switching element of the converter such that the input voltage becomes the target input voltage
Implementation Method 2
an inverter that converts a DC power into an AC power and supplies the AC power to the motor
Data Source
AI summary
The present motor control device includes an inverter, a converter, and a control device. The control device has a rotation speed calculation unit that calculates a rotation speed of a motor; an optimum voltage calculation unit that calculates an optimum input voltage; a minimum voltage calculation unit that calculates a minimum input voltage required to operate the motor at a motor operating point; and a target value setting unit that sets either one of the optimum input voltage and the minimum input voltage as a target input voltage. In a case in which the set target torque exceeds a predetermined value, the target value setting unit sets the minimum input voltage lower than the optimum input voltage as the target input voltage.