Interleaved Voltage-Doubler AC-DC Conversion for Extended Gain
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Solution Overview
Problem
Conventional AC-DC power conversion systems face limitations in achieving extended voltage gain, particularly at low AC input voltages, leading to increased conduction losses and reduced efficiency due to high duty-cycle operations and large output capacitors required for voltage regulation.
Innovation Solution
A bidirectional AC-DC power conversion system incorporating two voltage-doubler stages and a totem-pole rectifier stage, which allows for active power factor correction and extended voltage gain without wide duty-cycle variations, enabling seamless power transfer between AC and DC ports with reduced conduction losses and smaller output capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional AC-DC power conversion systems operate at high duty-cycle to achieve extended voltage gain at low AC input voltages, then voltage gain is improved, but conduction losses increase and efficiency decreases
Solution Approach 1:
The power conversion system is divided into two independent voltage-doubler stages, each capable of providing voltage gain. By segmenting the voltage multiplication function across multiple stages rather than relying on a single high-duty-cycle operation, the system achieves extended voltage gain while maintaining lower duty-cycles and reducing conduction losses in each stage.
Solution Approach 2:
The patent introduces a temporal dimension to voltage gain by using interleaved operation of two voltage-doubler stages. Instead of achieving voltage gain solely through duty-cycle control in a single stage, the system uses phase-shifted switching of multiple stages to accumulate voltage gain over time, effectively trading duty-cycle for multi-stage interleaved operation.
2Stability of the object's composition
If conventional AC-DC power conversion systems use large output capacitors to regulate DC output voltage, then voltage regulation is improved, but device complexity and size increase
Solution Approach 1:
The output capacitance requirement is segmented across two interleaved voltage-doubler stages. Each stage handles half of the power transfer duty, allowing each stage to use a smaller output capacitor. The interleaved operation ensures that when one stage is discharging its capacitor, the other is charging, effectively sharing the energy storage burden and reducing individual capacitor sizes while maintaining overall voltage regulation.
Solution Approach 2:
The interleaved operation of two voltage-doubler stages ensures continuous power transfer to the output, with one stage always available to supply power while the other is being charged. This continuous action reduces the energy storage requirement for each individual capacitor, as the system does not need to store enough energy for the entire output capacitance in a single stage.
3Loss of energy
If totem-pole configuration uses IGBTs with fast recovery antiparallel diodes, then reverse recovery loss is reduced, but device complexity increases compared to silicon MOSFETs
Solution Approach 1:
The patent changes the material parameter of the semiconductor devices from conventional silicon to wide-bandgap materials (such as GaN or SiC). This parameter change enables the use of MOSFETs with intrinsic body diodes that have negligible reverse recovery loss, eliminating the need for separate fast recovery diodes and simplifying the device structure while maintaining low reverse recovery losses.
4Power
If half-bridge PFC topology is used to achieve voltage-doubler characteristic, then voltage gain is improved, but output capacitor size increases significantly
Solution Approach 1:
The voltage-doubler function is segmented into two separate voltage-doubler stages operating in parallel with interleaved switching. Each stage provides partial voltage gain, and together they achieve the overall voltage-doubler characteristic. This segmentation allows each stage to use smaller capacitors compared to a single half-bridge topology that would require one large output capacitor.
Solution Approach 2:
The patent adds a spatial dimension by using two parallel voltage-doubler stages instead of a single half-bridge stage. The interleaved switching creates a temporal pattern where the stages operate out of phase, effectively distributing the energy storage requirement across both stages and reducing the size of individual output capacitors while maintaining the voltage-doubler characteristic.
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 enhanced current ripple cancellation and improved efficiency by reducing the need for large output capacitors and minimizing conduction losses, making it suitable for low AC-voltage applications with extended voltage gain characteristics.
Implementation Method 1
Each voltage-doubler stage includes a first inductor coupled between the AC voltage source and a junction point of the voltage-doubler stages
Implementation Method 2
Each voltage-doubler stage includes first and second switches connected in series across the first and second terminals of the voltage-doubler stage and connected at a common node, a third switch and a capacitor connected in series between the common node and the third terminal
Data Source
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AI summary
An AC-DC power conversion system (400) provides extended voltage gain characteristic by virtue of controlling a duty cycle of operation associated with the desired input-to-output gain. The AC-DC power conversion system (400) includes an AC-stage, first and second inductors (L1, L2), first and second voltage-doubler stages (401a, 401b), a totem-pole rectifier stage (402), and a DC-stage (403) coupled across the totem-pole rectifier stage (402). Each voltage-doubler stage (401a, 401b) includes a first terminal, a second terminal, and a third terminal, wherein a first terminal of the AC-stage is coupled by the first inductor (L1) to the first terminal of each voltage-doubler stage (401a, 401b) and by the second inductor (L2) to the third terminal of each voltage-doubler stage (401a, 401b). The totem-pole rectifier stage (402) includes first and second terminals coupled, respectively, to the second terminal of the first voltage-doubler stage (401a) and the second terminal of the second voltage-doubler stage (401b).