Motor Inverter Isolation for Induced Voltage Protection
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Solution Overview
Problem
Existing motor control systems for electric vehicles and ships fail to protect inverter circuits and their peripherals from induced voltages when the motor rotates due to external forces, leading to potential overheating, ignition, and circuit failure.
Innovation Solution
A control device with a processor that generates commands to disconnect the inverter circuit from the motor coil when rotation is detected without power supply, using a switching circuit to prevent voltage-induced damage, ensuring simple and reliable circuit protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor rotates due to external force when not in operation, then induced voltage is generated in motor coil, but inverter circuit and battery may fail due to overvoltage and heat generation
Solution Approach 1:
The control device applies preliminary anti-action by detecting motor rotation through current sensing and proactively controlling the switching circuit to disconnect the inverter circuit from the motor coil before induced overvoltage can damage the circuit. The processor monitors current to detect rotation and issues disconnection commands in advance to prevent harmful effects.
Solution Approach 2:
The switching circuit acts as an intermediary component between the inverter circuit and motor coil. It mediates the connection state, allowing normal operation when connected and providing protection when disconnected. The switching circuit responds to processor commands to switch between connected and disconnected states based on rotation detection.
2Temperature
If Patent Document 1's power conversion device consumes regenerative power, then inverter cooling is improved, but cooler cost increases to achieve sufficient cooling performance
Solution Approach 1:
The invention extracts the cooling function from the inverter circuit by introducing a separate switching circuit that isolates the inverter from the motor coil during rotation. This extraction prevents heat generation at the source, eliminating the need for expensive high-performance coolers and reducing overall system cost.
Solution Approach 2:
The switching circuit provides beforehand cushioning by preventing heat generation in the inverter circuit before it occurs. By disconnecting the inverter from the motor coil upon detecting rotation, the system prevents thermal stress and eliminates the need for expensive cooling solutions, cushioning against future thermal damage.
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
Effectively protects inverter circuits and peripherals from induced voltages, preventing overheating and failure by disconnecting the inverter circuit from the motor coil during external rotation, thus ensuring high reliability and cost-effective cooling solutions.
Implementation Method 1
if a motor rotates due to an external force when the motor is not in operation, an induced voltage is generated in a motor coil
Data Source
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AI summary
A control device 10 for a motor 1 includes: a processor 20 for generating a control command for power supplied to a coil 2 of the motor 1; an inverter circuit 30 for controlling, based on the control command of the processor 20, the power supplied to the coil 2 of the motor 1; and a switching circuit 60 disposed between the inverter circuit 30 and the coil 2 of the motor 1, and configured to switch between an energized state where the inverter circuit 30 and the coil 2 are energized and a non-energized state where the inverter circuit 30 is electrically disconnected from the coil 2. The processor 20 is configured to give the switching circuit 60 a first disconnection command to switch from the energized state to the non-energized state, when rotation of the motor 1 is detected in a state where the power is not supplied to the coil 2.