Parallel Power Converter Control for Seamless Backup Switching
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Solution Overview
Problem
Mechanical relays in power devices take several milliseconds to transition between power sources, leading to energy shortages during mode transitions, and charging capacitors to higher voltages to compensate introduces increased losses and costs.
Innovation Solution
Implementing a system with parallel-connected power devices where one operates actively and one in standby, maintaining capacitors at different voltage levels to ensure seamless transitions with minimized losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical relays are used to transition between power sources, then power switching can be achieved, but transition time increases (several milliseconds) causing energy shortages
Solution Approach 1:
The system divides the power supply function into multiple parallel power devices (first power device and second power device), each capable of independently providing power. This segmentation allows one device to be active while another is on standby, enabling seamless transitions without relying on slow mechanical relay switching.
Solution Approach 2:
The standby power device is pre-configured and kept ready to immediately take over power provision when needed. The system maintains a standby power device with capacitors charged to a higher voltage level, so when a transition is needed, the standby device can immediately become active without waiting for mechanical relay transitions.
2Reliability
If capacitors are charged to higher voltages to compensate for transition energy shortages, then power continuity is improved, but energy losses and costs increase
Solution Approach 1:
The system applies different voltage levels to different power devices based on their operational state. The standby power device maintains capacitors at a higher voltage level (second voltage) to ensure immediate power availability, while the active power device operates at a lower voltage (first voltage), optimizing overall energy efficiency and reducing losses.
3Reliability
If multiple power devices operate in parallel, then seamless transitions are enabled, but system complexity increases
Solution Approach 1:
The system combines multiple power devices in parallel configuration, where each device has similar functional capabilities. This merging approach allows the system to leverage the collective capacity of multiple devices while using a controller to manage their coordination, achieving seamless transitions through standardized control logic.
Data Source
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AI summary
Examples of the disclosure include a power system including a first device (302) having a first converter (112a) and a first DC bus, a second device (304) having a second converter (112b) and a second DC bus, an output coupled to a load, and at least one controller (116a, 116b) configured to control, in a mains mode, the first device to be in an active state, control the first converter to maintain the first DC bus at an active voltage in the active state of the first device, control, in the mains mode, the second device to be in a standby state, control the second converter to maintain the second DC bus at a standby voltage higher than the active voltage in the standby state of the second device, and control the second converter to transition to the active state responsive to initiating a transition from the mains mode to a backup mode.