Gate Drive Circuit Abnormality Detection for UPS Reliability
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Solution Overview
Problem
Uninterruptible power supply systems face malfunctions in switching elements due to unsteady gate potentials when an abnormality occurs in the power source for gate drive circuits, leading to erroneous switching states.
Innovation Solution
Incorporating a controller with an abnormality detection circuit that switches from inverter power supply to bypass AC power supply, maintaining the gate potential of switching elements during the transition to prevent malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate drive circuit power source continues to supply power during abnormality detection, then the gate potential remains stable, but the abnormality cannot be detected and switched off in time causing continuous malfunction risk
Solution Approach 1:
The abnormality detection circuit continuously monitors the power source voltage and provides real-time feedback to the controller. When the voltage falls outside the predetermined range, the feedback signal triggers immediate switching action. This closed-loop feedback mechanism ensures both timely abnormality detection and continuous gate potential stability by maintaining appropriate power supply levels.
2Reliability
If the system uses a bypass AC power source for power supply, then the load receives uninterrupted power, but the gate drive circuit may not receive adequate power causing gate potential instability
Solution Approach 1:
The controller acts as an intermediary between the bypass AC power source and the gate drive circuit. It manages the power distribution by switching the bypass power source to supply both the load and the gate drive circuit simultaneously through controlled switching elements. This intermediary control ensures that the gate drive circuit receives adequate power for stable gate potential while the load receives uninterrupted power supply.
Data Source
AI summary
A plurality of gate drive circuits each drive a gate of a corresponding one of a plurality of switching elements included in a converter and an inverter. Each gate drive circuit includes a gate driver and a power source circuit. The gate driver drives the gate potential of the switching element to a potential corresponding to H or L level, in accordance with the gate signal input from a controller to the gate electrode of the switching element. The power source circuit supplies power to the gate driver. When a first switch is ON and a second switch is OFF, the controller, upon detection of an abnormality of the power source circuit of the gate drive circuit, turns on the second switch and turns off the first switch. The gate drive circuit maintains the gate potential of the switching element during the period from when the abnormality of the power source circuit is detected to when the second switch is turned on.