Switch Short-Circuit Detection Using Open-State Voltage Comparison
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Solution Overview
Problem
Existing systems fail to quickly and easily detect a short-circuit state in switches that disconnect three-phase motors from inverters, leading to potential electrical connection issues and increased energy consumption when an abnormality is not promptly identified.
Innovation Solution
A detection apparatus is introduced, featuring a switch determination resistor and a detection unit that compares pre-memorized voltages with real-time measurements to determine if a switch is in a short-circuit state, using a configuration with high-side and low-side switching elements connected in series between power supply lines, allowing for rapid identification of switch abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switch is controlled to be open to disconnect the three-phase motor and inverter, then the current path is cut off and energy consumption is reduced, but the detection of short-circuit state becomes more difficult and time-consuming
Solution Approach 1:
The detection apparatus performs short-circuit detection of the switch before the vehicle operation begins. The control device controls the switch to be in an open state prior to operation, and the detection apparatus detects whether the switch is in a short-circuit state while it is open, enabling advance detection before energy consumption becomes an issue.
Solution Approach 2:
The detection apparatus uses an intermediary detection mechanism that can sense the short-circuit state of the switch without requiring the switch to be closed. By detecting voltage or current characteristics through the open switch, the system can identify short-circuits without creating a direct current path between the inverter and motor.
2Power
If the abnormality detection is delayed, then the system can operate with higher output power, but the three-phase motor is applied with unexpected load and additional energy is required
Solution Approach 1:
The system performs abnormality detection of the switch before vehicle operation begins. By detecting short-circuit states in advance when the switch is open and the motor is not under load, the system can identify issues before they cause unexpected energy consumption during high-power operation.
Solution Approach 2:
The detection apparatus provides feedback about the switch status to the control device. Based on this feedback, the control device can determine whether to proceed with normal operation or take corrective action, preventing unexpected energy consumption that would result from operating with a faulty switch.
3Productivity
If the switch short-circuit is not detected in advance, then the system maintains full operational capacity, but the current path cannot be properly separated when abnormality occurs
Solution Approach 1:
The detection apparatus detects short-circuit abnormalities of the switch before vehicle operation begins. This preliminary detection ensures that the system knows the actual status of the switch, allowing reliable electrical separation to be implemented when needed, while maintaining full operational capacity when the switch is functioning properly.
Solution Approach 2:
By detecting switch short-circuits in advance, the system prepares for potential failures before they occur. This beforehand detection acts as a cushioning measure, preventing unreliable electrical separation during operation by identifying issues that would compromise separation reliability.
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
The apparatus enables quick and accurate detection of short circuits in switches, preventing electrical misconnections and optimizing energy usage by identifying abnormal switch operations before vehicle operation begins.
Implementation Method 1
a detection portion detecting voltages of terminals which are included in the three switches, respectively, and which are connected to the inverter
Implementation Method 2
a switch determination resistor provided between the first power supply line and at least one of three terminals included in the three-phase motor
Data Source
Figure 1
Figure 2
AI summary
A detection apparatus (1) includes a switch determination resistor (11), a detection portion (12) detecting voltages of terminals which are included in the three switches (6, 6U, 6V, 6W), respectively, and which are connected to the inverter (4), and a determination portion (13) previously memorizing the voltages of the terminals of the three switches (6, 6U, 6V, 6W) being acquired in a state where the three switches (6, 6U, 6V, 6W) are in an open state, the determination portion (13) determining the switch in the short-circuit state in the three switches (6, 6U, 6V, 6W) based on the voltages of the terminals of the three switches (6, 6U, 6V, 6W) which are previously memorized and a detection result of the detection portion (12) in a case where the three switches (6, 6U, 6V, 6W) are controlled to be in the open state.