Series-Input Parallel-Output Converter Voltage Balancing
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Solution Overview
Problem
Existing methods for balancing input voltages of power converters with series-connected inputs and parallel-connected outputs are inefficient, either leading to excessive power loss, increased cost, or poor regulation of input and output voltages, especially when converters and capacitors mismatch.
Innovation Solution
The method involves independently regulating input and output voltages using separate controllers for each converter, with an output regulating controller managing the output voltage and input regulating controllers managing their respective input voltages, allowing for tight regulation of both without additional power components, and using a delay circuit to synchronize startup operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistor voltage-balancing method is used, then capacitor impedance mismatching is compensated, but power loss increases and conversion efficiency decreases
Solution Approach 1:
The patent implements feedback control by sensing the input voltages of each converter and using the controller to adjust the duty cycle of the switches. This closed-loop feedback mechanism dynamically compensates for voltage imbalances caused by capacitor impedance mismatching without requiring resistive balancing, thereby eliminating the associated power losses while maintaining reliable voltage balance.
2Reliability
If totem-pole switch configuration with inductor is used, then large converter input current mismatching is handled effectively, but additional power components increase cost and decrease efficiency
Solution Approach 1:
The patent makes the existing switches in each converter perform multiple functions: they simultaneously regulate the output voltage and balance the input voltages of series-connected converters by independent duty cycle control. This eliminates the need for separate totem-pole switch configurations and additional inductors, reducing device complexity and cost while maintaining effective voltage balancing for large current mismatches.
3Loss of energy
If voltage balancing is implemented solely at control level, then efficiency and power density are maintained, but input voltage balancing is poor and tight regulation is not achieved
Solution Approach 1:
The patent implements dynamic independent duty cycle control for each converter through separate controllers. This dynamic control allows each converter to adjust its switching parameters in real-time based on its specific input voltage conditions, achieving tight input voltage balancing and regulation without requiring additional power components that would reduce efficiency. The system adapts continuously to maintain precise voltage control.
Data Source
AI summary
A power supply is coupled to an input voltage source. The power supply includes a plurality of converters. Each converter has an input for receiving an input voltage and an output for providing an output voltage. The inputs are connected in series and the outputs are connected in parallel to provide an output voltage. The power supply further includes an output regulating controller coupled to one of the plurality of converters for regulating the output voltage. The power supply further includes one or more input regulating controllers correspondingly coupled to the remaining one or more converters of the plurality of converters for regulating one or more input voltages.