Direct-current power supply device, motor drive device, blower, compressor, and air conditioner
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Solution Overview
Problem
Existing direct-current power supply devices require additional current detectors to detect overcurrent, leading to increased costs and reduced reliability due to the increased parts count.
Innovation Solution
A direct-current power supply device with a reactor, bridge circuit, capacitor, and dual current detectors that determine overcurrent based on alternating and direct current values, allowing the bridge circuit to stop operation when either detector indicates an overcurrent, reducing the need for additional current detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shunt resistors are inserted at two different locations for overcurrent detection, then overcurrent detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The first current detector serves dual purposes: it detects overcurrent on the AC side and also provides current information for normal control operations. This multi-functionality eliminates the need for separate shunt resistors at both locations, reducing parts count while maintaining overcurrent detection capability
Solution Approach 2:
The patent combines the overcurrent detection function with the normal control current detection function into a single first current detector configuration. By merging these functions and strategically placing only one current detector on the AC side with intelligent control logic, the system achieves both overcurrent protection and normal operation monitoring without requiring two separate detection devices
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
Enables overcurrent detection in direct-current power supply devices with a reduced additional current detector count, enhancing reliability and cost-effectiveness.
Implementation Method 1
a reactor having one end connected to an alternating-current power supply
Implementation Method 2
a bridge circuit that is connected to another end of the reactor and converts a first voltage that is an alternating-current output of the alternating-current power supply into a direct-current voltage
Implementation Method 3
a capacitor that smoothes a second voltage that is the direct-current voltage of the bridge circuit
Data Source
AI summary
A direct-current power supply device includes a reactor, a bridge circuit that converts alternating-current voltage output from an alternating-current power supply, which is connected to the reactor, into direct-current voltage, a capacitor that smoothes the output voltage of the bridge circuit, a current detector that detects a first current flowing as an alternating current between the alternating-current power supply and the bridge circuit, a current detector that detects a second current flowing as a direct current between the bridge circuit and the capacitor, an overcurrent determination unit that determines on the basis of a detected first current value whether or not the first current is an overcurrent, and an overcurrent determination unit that determines on the basis of a detected second current value whether or not the second current is an overcurrent. The bridge circuit stops operating when a determination result of either the overcurrent determination unit or the overcurrent determination unit indicates an overcurrent.