Method and apparatus for detecting inter-phase short-circuit of three-phase motor and air conditioner including the same
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Solution Overview
Problem
Inter-phase short-circuits in power converters for air conditioners can lead to overcurrent situations, potentially damaging motors and inverter devices due to the lack of efficient detection methods.
Innovation Solution
A method and apparatus that utilize a power converter with a controller to control the gate driver of high-side and low-side switching elements in the inverter, allowing current to partially short-circuit and flow through a current sensor to detect inter-phase short-circuits by comparing the sensed current with a threshold voltage, enabling rapid identification of short-circuit paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional overcurrent protection methods are used, then device damage is prevented, but detection speed is insufficient and damage may occur before detection
Solution Approach 1:
The patent applies preliminary action by performing short-circuit detection before normal motor operation begins. The controller drives the inverter in a short-circuit detection mode where specific switching elements are activated to intentionally create current paths that would indicate a short-circuit condition. This allows the system to detect potential faults before they cause damage during actual motor operation, resolving the contradiction by enabling early detection without waiting for harmful overcurrent conditions to develop.
Solution Approach 2:
The patent implements continuous useful action by integrating the short-circuit detection function into the existing inverter circuitry without requiring separate detection equipment. The same switching elements and current sensors used for motor control are utilized for detection purposes, ensuring that the detection process is continuous and seamlessly integrated into the system's operational framework, thus maintaining high detection speed while ensuring reliable detection.
2Reliability
If additional detection circuits are added to improve detection capability, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the inverter circuit to serve dual purposes: motor control and short-circuit detection. The switching elements (first through sixth switching elements) and current sensors are configured to perform both normal motor drive functions and detection functions. By making the detection capability inherent to the existing circuit components rather than adding separate detection circuits, the system achieves reliable short-circuit detection without increasing device complexity.
Solution Approach 2:
The patent implements self-service by enabling the inverter system to detect its own faults using its own components. The controller utilizes the existing current sensors and switching elements to monitor for short-circuit conditions without requiring external detection equipment. This self-diagnostic capability allows the system to maintain high detection reliability while avoiding the added complexity of separate detection circuits.
Data Source
AI summary
The present disclosure relates to inter-phase short-circuit detection, and particularly, to a method and apparatus for detecting inter-phase short-circuit of a three-phase motor, and an air conditioner including the same. The apparatus for detecting inter-phase short-circuit of a three-phase motor includes: a power supply for rectifying AC power to supply DC power; an inverter for generating three-phase current for driving the three-phase motor using the DC power, the inverter including a plurality of switching elements including high-side switching elements and low-side switching elements corresponding to three phases, and a current sensor commonly connected to the switching elements; a gate driver for driving the plurality of switching elements; and a controller for controlling the gate driver such that current flowing through the high-side switching elements and current flowing through the low-side switching elements partially short-circuit to sense a current flowing through the current sensor and determine inter-phase short-circuit.