Motor Control Device Parallel Switching Failure Segmentation
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Solution Overview
Problem
In motor driving devices, when a failure is detected in one relay, all connected motors are stopped, even if other motors can operate normally, impairing user convenience.
Innovation Solution
A motor control device with a power converter supplying three-phase voltage to two motors, a switching device with two-phase switches, and a controller that identifies the failure position by detecting no current flow and adjusts the switches to maintain operation of operable motors without stopping all motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system power source is turned off when a relay failure is detected, then safety is ensured, but all motors are stopped even when other motors can operate normally, impairing user convenience
Solution Approach 1:
The power distribution system is segmented into independent branches, each with its own switching device. When a failure is detected in one relay or switching device, only the affected branch is isolated while other branches continue to operate normally, allowing selective operation of individual motors rather than shutting down the entire system
2Reliability
If all motors are stopped when one relay failure is detected, then system safety is maintained, but productivity is reduced due to complete system shutdown
Solution Approach 1:
The system is divided into independent motor branches with separate switching devices. Upon detecting a relay or switching device failure, the control device isolates only the affected branch while maintaining operation of other branches, thereby preserving overall system productivity rather than forcing a complete shutdown
Solution Approach 2:
The system maintains continuous operation of functional motor branches even when one branch experiences a relay or switching device failure. The control device enables the motor control device to continue driving operable motors, ensuring uninterrupted useful action and productivity
3Reliability
If the switching device state is not adjusted after failure detection, then the failed motor cannot operate, but other motors are unnecessarily stopped
Solution Approach 1:
The control device continuously monitors the state of switching devices and motor operation. When a relay or switching device failure is detected through feedback signals, the control device automatically adjusts the switching state of other relays to maintain operation of functional motors, using real-time feedback to optimize system performance
Solution Approach 2:
The switching device states are made dynamic and adaptable based on real-time failure detection. The control device can change the on/off state of switching devices in response to detected failures, allowing the system to dynamically reconfigure and maintain operation of healthy motors rather than maintaining a static shutdown state
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
Enables continuous operation of some motors without stopping all motors when a switching device failure occurs, enhancing user convenience by allowing emergency operation and maintaining air-conditioning apparatus functionality.
Implementation Method 1
a power converter that converts a power into a three-phase voltage and supplies the three-phase voltage to two motors being connected in parallel
Implementation Method 2
a current detection device that detects three-phase currents flowing in the two motors
Implementation Method 3
a switching device having two switches that are provided on power lines of two phases of the branch three-phase power line and switch between an on-state and an off-state, the on-state being a state in which the power line of the corresponding phase is electrically connected between the other motor and the power converter, the off-state being a state in which the power line thereof is disconnected
Data Source
AI summary
A motor control device includes a power converter that supplies a three-phase voltage to two motors being connected in parallel, a three-phase power line that connects between one of the two motors and the power converter, a branch three-phase power line that connects between the other of the two motors and the power converter, a switching device having two switches that are provided on the branch three-phase power line, a current detection device that detects three-phase currents flowing in the two motors, and a controller. The controller performs a failure determination of the switching device by identifying a phase of a power line in which no current flows in the three-phase power line and the branch three-phase power line, and, when a failure is detected in one of the two switches in the failure determination, controls to change a state of the other switch, which operates normally, to coincide with a state of the failed switch.