Rectifier Inverter UPS with Dynamic Power Sharing
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Solution Overview
Problem
Conventional uninterruptible power supplies (UPS) face challenges in providing stable AC and DC power, particularly during main AC source interruptions, where voltage regulation and power flow management are not effectively handled, leading to inefficiencies and potential power quality issues.
Innovation Solution
The proposed UPS system includes a rectifier and inverter configuration with a control module that converts AC input voltage to DC and back to AC, with a secondary power source for backup, enabling dynamic power flow adjustment and voltage regulation, and includes features like power factor correction and relay-based bypass circuits to manage power distribution between AC and DC loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is supplied from the battery to the rectifier during AC source interruption, then the AC load can be powered without interruption, but the rectifier operates as a DC-to-DC boost converter which increases system complexity
Solution Approach 1:
The rectifier is designed to perform multiple functions: during normal operation it converts AC to DC and charges the battery, during AC interruption it acts as a DC-to-DC boost converter to power the inverter from the battery. This multi-functionality eliminates the need for separate power conversion stages and reduces overall system complexity despite the dual operating modes.
Solution Approach 2:
The rectifier dynamically changes its operating mode based on the state of the AC source. When AC power is available, it operates as an AC-to-DC converter; when AC power is interrupted, it transitions to DC-to-DC boost converter mode. This dynamic adaptation allows a single device to handle multiple power scenarios without requiring redundant hardware.
2Device complexity
If the battery backup is directly connected to the DC bus, then the battery can charge without a separate charger, but the DC bus voltage is not regulated and decreases as energy is drawn
Solution Approach 1:
The control module continuously monitors the DC bus voltage and adjusts the rectifier's operation to maintain regulated voltage. When the DC bus voltage drops below a threshold, the control module activates the rectifier to boost the voltage from the battery back to the required level, ensuring stable operation of DC-connected loads throughout the discharge cycle.
Solution Approach 2:
The rectifier serves as an intermediary between the battery and the DC bus, not just as a simple connection. It actively regulates the voltage transfer, preventing the DC bus voltage from dropping as the battery discharges. This intermediary function maintains voltage stability without requiring a separate voltage regulator on the DC bus.
3Adaptability or versatility
If an offline UPS configuration is used with relays, then both AC and DC power can be provided, but the AC load receives unfiltered and unregulated utility power
Solution Approach 1:
The patent combines online UPS topology (with rectifier-inverter conversion) and offline UPS topology (with direct AC connection) into a single system. The AC load can receive power through the rectifier-inverter path for filtered and regulated output, or through the direct relay path for unfiltered output, providing both power quality options and DC power capability in one system.
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 ensures uninterrupted and regulated AC and DC power supply, improves power efficiency by eliminating the need for external AC-to-DC conversion, and allows for dynamic power sharing between AC and DC loads, enhancing reliability and reducing energy consumption.
Implementation Method 1
A rectifier converts an alternating current input voltage to a first direct current voltage
Implementation Method 2
An inverter converts the first direct current voltage to an alternating current output voltage
Implementation Method 3
A backup power source, such as a battery, that is used to supply power when power from a main power source is interrupted
Data Source
AI summary
A power supply includes a rectifier that converts an alternating current input voltage to a first direct current voltage. An inverter that converts the first direct current voltage to an alternating current output voltage. A first set of output terminals that receives the alternating current output voltage. A second set of output terminals that receives the first direct current voltage. A charging circuit that charges a backup power source based on the first direct current voltage. The rectifier receives a second direct current voltage from the backup power source based on the power supply operating in a predetermined condition.