DC Bus Short Circuit Detection Using Reduced Test Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for detecting short circuits in direct current buses within inverters fail to identify faults at lower test voltages, potentially causing damage to electric motors and inverter circuitry due to the inability to detect failures in power switching semiconductors before they lead to short circuits.
Innovation Solution
A system comprising a direct current bus with capacitors for voltage regulation, thermal circuits for temperature monitoring, and logic devices coupled with buffer memory and electronic data processing systems to detect short circuits using test voltages lower than operational voltages, thereby minimizing damage by identifying faults before they escalate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If testing is performed at operational voltage levels, then detection accuracy is improved, but damage to motors and inverter circuitry occurs
Solution Approach 1:
The patent applies parameter changes by testing the direct current bus at reduced voltage levels (below operational voltage) rather than at full operational voltage. This allows short circuit detection to be performed safely without causing damage to the motor or inverter circuitry, while still maintaining sufficient detection accuracy to identify faults in power switching semiconductors.
2Object-affected harmful factors
If testing is performed at lower voltage levels, then damage to circuitry is minimized, but detection capability is reduced
Solution Approach 1:
The patent implements preliminary action by performing short circuit detection tests at reduced voltage levels before the inverter is fully operational or before damage can occur. The control device activates the direct current bus at a reduced voltage state to test for short circuits, thereby preventing damage while still enabling fault detection through preliminary testing.
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 detects short circuits at lower test voltages, reducing the risk of damage to motors and inverter circuitry by triggering protective measures before operational voltage levels are reached, ensuring reliable operation and minimizing damage.
Implementation Method 1
A capacitor connected in parallel across the terminals of the direct current bus. The capacitor filters the direct current and keeps the voltage on the direct current bus at a substantially uniform level
Implementation Method 2
A first thermal circuit associated with the supply for detecting whether the supply exceeds an operational temperature threshold
Implementation Method 3
A supply adapted to generate a test voltage that is lower than an operational voltage of the direct current bus. A first thermal circuit associated with the supply for detecting whether the supply exceeds an operational temperature threshold
Data Source
Figure 1
Figure 2
AI summary
The system (211) comprises a direct current bus (33) having a positive terminal (36) and a negative terminal (38). A first switching transistor (104) and a second switching transistor (106) have their respective switched terminals connected in series mm respect to each other between the positive terminal (38) and the negative terminal (38), A primary supply (16) is arranged to generating a test voltage that is lower than an operational voltage of the direct current bus (33), The test voltage is applied between the positive terminal (36) and the negative terminal (38) of the direct current bus (33). A primary thermal circuit (222) is associated with the supply (16) for detecting whether the supply exceeds an operational temperature threshold. The thermal circuit (222) provides a signal or logic level state Indicative of a detected short circuit In the direct, current bus (33) if the primary supply (16) exceeds the operational temperature threshold.