Inverter Control Device Turn-Off Failure Management
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Solution Overview
Problem
Existing inverter control systems fail to effectively perform fail-safe control when a switching element experiences a turn-off failure, leading to unbalanced currents and potential excessive heat in sound switching elements.
Innovation Solution
The inverter control device implements torque reduction control or deceleration control by performing switching control of the switching elements to manage current flow and facilitate a smooth transition to shutdown, even if one switching element is in a persistent off state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active short-circuit control is performed when a turn-off failure occurs in a switching element, then fail-safe control is attempted, but current balance is lost and excessive current flows through sound switching elements causing heat generation
Solution Approach 1:
The patent inverts the conventional active short-circuit control approach by detecting turn-off failures before executing short-circuit control. When a turn-off failure is detected in a switching element, the system identifies this condition and avoids performing active short-circuit control that would otherwise cause current imbalance. Instead, the system transitions directly to shutdown control or alternative safe operating modes, preventing the harmful current flow through sound switching elements.
2Device complexity
If conventional fail-safe control is implemented without turn-off failure detection, then control simplicity is maintained, but inappropriate control actions are taken leading to system damage
Solution Approach 1:
The patent implements preliminary detection of turn-off failures in switching elements before executing any fail-safe control actions. The control unit continuously monitors switching element states and identifies turn-off failures in advance. This preliminary detection enables the system to select the appropriate fail-safe control strategy (shutdown control, active short-circuit control, or other modes) based on the actual failure condition, ensuring control appropriateness without significantly increasing system complexity.
Data Source
AI summary
An inverter control device that controls an inverter connected to a direct-current power supply and connected to an alternating-current rotating electrical machine to convert electric power between direct current and alternating current of a plurality of phases, the inverter control device including an electronic control unit that is configured to perform, in a state in which one switching element of a plurality of switching elements included in the inverter has a turn-off failure in which the switching element always goes into an off state, torque reduction control for reducing torque of the rotating electrical machine or deceleration control for outputting torque in a reverse direction from a rotation direction of the rotating electrical machine by performing switching control of the plurality of switching elements.