Parallel UPS Current Equalization With Harmonic Compensation
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Solution Overview
Problem
Existing uninterruptible power supply (UPS) systems inject large harmonic and reactive currents into the power grid when operating in an economical mode (ECO mode), leading to grid pollution and inefficiencies, and current equalization methods require additional components that increase costs and energy loss.
Innovation Solution
A power supply system with multiple UPSs connected in parallel, each equipped with a control module that collects and compensates harmonic and reactive currents without additional components by adjusting the duration of power grid connection and using direct current to alternating current conversion modules, ensuring equalized current output and minimizing grid pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If UPSs run in ECO mode to provide stable power supply with high efficiency, then power supply efficiency is improved, but large harmonic current and reactive current are injected into the power grid causing pollution
Solution Approach 1:
The patent converts the harmful harmonic current and reactive current injected by UPSs into a beneficial control signal. The control module detects these currents and uses them to generate compensation signals that adjust the bypass switch module's conduction angle, thereby eliminating the pollution while maintaining ECO mode operation
Solution Approach 2:
The patent implements a feedback mechanism where the control module continuously monitors the harmonic current and reactive current injected into the power grid, and adjusts the bypass switch module's conduction angle based on this feedback to minimize grid pollution while maintaining high efficiency
2Reliability
If current equalization adjustment is performed on currents provided by multiple UPSs to improve reliability and loading capability, then system reliability is improved, but the pollution to the power grid becomes more serious
Solution Approach 1:
The patent merges the current equalization function with the harmonic compensation function into a single control mechanism. The control module simultaneously performs both current equalization among multiple UPSs and harmonic current compensation by adjusting the bypass switch module's conduction angle, achieving both goals without separate components
Solution Approach 2:
The bypass switch module is designed to perform multiple functions: it provides power transmission in ECO mode, performs current equalization among parallel UPSs, and compensates for harmonic currents and reactive currents. This multi-functionality eliminates the need for additional components while resolving the contradiction
3Object-generated harmful factors
If direct current to alternating current conversion module is used to compensate current harmonic or reactive current, then power grid pollution is minimized, but device complexity increases
Solution Approach 1:
The patent makes the bypass switch module multi-functional by enabling it to perform both power transmission and harmonic compensation functions. Through pulse width modulation control of the bypass switch's conduction angle, the module can compensate for harmonic currents and reactive currents without requiring a separate direct current to alternating current conversion module, thus reducing system complexity
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
The system achieves high power supply efficiency, loading capability, and reduced grid pollution by equalizing currents within the UPSs, improving reliability and efficiency without additional hardware.
Implementation Method 1
a direct current to alternating current conversion module, configured to output a current to an output terminal
Data Source
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AI summary
This application provides a power supply system, a power supply method, a control apparatus, and a computer storage medium, which have high power supply efficiency, high loading capability, and little pollution to a harmonic current and a reactive current in a power grid, and do not require an additional component. The power supply system includes a plurality of parallelly-connected uninterruptible power supplies UPSs, and each UPS collects a first current of the UPS within a collection period in a first duration. In a current equalization period in the first duration, a direct current to alternating current conversion module is controlled to output a first compensation current, where the first compensation current includes a first compensation reactive current component and/or a first quantity of first compensation harmonic components; one first compensation reactive current component in the first quantity of first compensation harmonic components and one harmonic component of the first current have a same frequency and opposite amplitudes; the first compensation reactive current component and the reactive current component have a same frequency and opposite amplitudes. A duration in which a bypass switch module connects a power grid to a load is adjusted, where the current equalization period does not completely overlap the collection period.