Inverter Rectifier Circuit for UPS Capacitor Precharging
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Solution Overview
Problem
Conventional uninterruptible power supply devices using electric double-layer capacitors require complex configurations and increased device size for precharging, especially during long power interruptions, as they need to be charged from 0V to a predetermined voltage.
Innovation Solution
The device incorporates a converter, an electric double-layer capacitor, an inverter, a rectifier circuit, and a charging circuit, where the rectifier circuit supplies power to the capacitor at the first startup and selectively uses output power from either the converter or rectifier circuit at subsequent startups, allowing for easy precharging with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bidirectional chopper circuit is provided between the converter and the electric double-layer capacitor to perform precharge, then the electric double-layer capacitor can be precharged from 0V to a predetermined voltage, but the device size increases and the device configuration becomes complicated
Solution Approach 1:
The inverter is made to perform multiple functions: its normal function of converting DC to AC power, and an additional function of precharging the electric double-layer capacitor by converting AC to DC through its rectifier circuit. This eliminates the need for a separate bidirectional chopper circuit dedicated to precharging, thereby reducing device complexity while maintaining precharge capability
Solution Approach 2:
The precharge function is merged with the inverter unit by utilizing the inverter's rectifier circuit. Instead of having separate precharge and power conversion devices, the patent combines these functions into a single integrated system where the inverter handles both AC-DC conversion for precharging and DC-AC conversion for power supply
2Reliability
If a bidirectional chopper circuit is provided between the converter and the electric double-layer capacitor to perform precharge, then the electric double-layer capacitor can be precharged from 0V to a predetermined voltage, but the device size increases
Solution Approach 1:
The precharge function is merged with the inverter unit by utilizing the inverter's rectifier circuit. Instead of having separate precharge and power conversion devices, the patent combines these functions into a single integrated system where the inverter handles both AC-DC conversion for precharging and DC-AC conversion for power supply
Solution Approach 2:
The inverter is made to perform multiple functions: its normal function of converting DC to AC power, and an additional function of precharging the electric double-layer capacitor by converting AC to DC through its rectifier circuit. This eliminates the need for a separate bidirectional chopper circuit dedicated to precharging, thereby reducing device complexity while maintaining precharge capability
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
This configuration enables easy precharging of the electric double-layer capacitor, reducing device complexity and size while maintaining reliable power supply during interruptions.
Implementation Method 1
a converter converting ac power into dc power
Implementation Method 2
an electric double-layer capacitor storing the dc power
Implementation Method 3
an inverter converting the dc power into ac power
Implementation Method 4
a rectifier circuit converting the second ac power into dc power
Data Source
AI summary
An uninterruptible power supply device including a rectifier circuit rectifying output power of an inverter. At a first startup of the inverter, output power of the rectifier circuit is supplied to an electric double-layer capacitor. At second and subsequent startups of the inverter, output power of one of a converter and the rectifier circuit is selectively supplied to the electric double-layer capacitor. Therefore, by controlling the inverter, the electric double-layer capacitor can be precharged easily with a simple configuration.