Power Conversion Device With Shared Bridge Circuit
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Solution Overview
Problem
Existing power conversion devices face challenges in efficiently controlling power transmission among three or more electric devices due to conflicting requirements that reduce efficiency and increase size and cost, such as the need for multiple full-bridge circuits and coils, and the inability to transmit power simultaneously between multiple devices.
Innovation Solution
A power conversion device with a first and second smoothing circuit, a bridge circuit connected to the smoothing circuits, and a transformer with a primary side connected to a third electric device, where a controller varies the duty ratio of the bridge circuit at a frequency higher than the cutoff frequencies of the smoothing circuits to control power exchange between the electric devices, allowing simultaneous power transmission among three or more devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple full-bridge circuits and coils are provided for each electric device, then power transmission control among multiple devices is achieved, but device size, weight, and cost increase
Solution Approach 1:
The patent merges multiple full-bridge circuits into a single shared full-bridge circuit that serves multiple electric devices. The transformer has multiple secondary coils that can be independently controlled through duty ratio modulation of the single full-bridge circuit, eliminating the need for separate full-bridge circuits for each device. This combining approach reduces the number of power conversion circuits while maintaining the capability to control power transmission among multiple devices independently.
Solution Approach 2:
The single full-bridge circuit is designed to perform multiple functions by serving different secondary coils of the transformer simultaneously. Each secondary coil can be independently controlled to connect to different electric devices, allowing the full-bridge circuit to adaptively serve multiple devices with different power requirements. The controller dynamically assigns the full-bridge circuit to different devices based on power transmission needs.
2Ease of operation
If the transformer secondary-side coil cuts off ripple current, then DC current is obtained between first and second electric devices, but power transmission efficiency decreases when ripple current is needed for third electric device
Solution Approach 1:
The transformer secondary side is segmented into multiple independent coils, each capable of serving different functions. One secondary coil can be configured to cut off ripple current for DC output to the first and second electric devices, while another secondary coil can allow ripple current to pass through to supply the third electric device. This segmentation allows independent optimization of current characteristics for different devices without compromising overall system efficiency.
3Adaptability or versatility
If self-inductance of transformer is switched according to situation, then power transmission between first and second devices is controlled, but simultaneous power transmission to third device is impossible
Solution Approach 1:
The system employs dynamic control of the full-bridge circuit's duty ratio at varying frequencies. The controller can dynamically adjust the switching frequency and duty ratio to accommodate different power transmission scenarios simultaneously. By using high-frequency switching control, the system can independently regulate power flow to multiple devices connected through different secondary coils of the transformer, enabling simultaneous power transmission while maintaining control flexibility.
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 enables efficient, bidirectional power transmission among three or more electric devices while reducing the size and cost of the power conversion device, eliminating conflicting design requirements and enhancing power transmission efficiency.
Implementation Method 1
a transformer having a primary side connected to a third electric device and a secondary side connected to the first bridge circuit and the second smoothing circuit
Implementation Method 2
the controller varies a duty ratio of the first bridge circuit at a frequency higher than a cutoff frequency of the first smoothing circuit and a cutoff frequency of the second smoothing circuit
Data Source
AI summary
A power conversion device includes: a first smoothing circuit connected to a first electric device; a second smoothing circuit connected to a second electric device; a first bridge circuit connected to the first smoothing circuit; a transformer having a primary side connected to a third electric device and a secondary side connected to the first bridge circuit and the second smoothing circuit; and a controller, wherein the controller varies a duty ratio of the first bridge circuit at a frequency higher than cutoff frequencies of the first and second smoothing circuits, controls a constant component of the duty ratio to control power exchange between the first and second electric devices, and controls a phase of a varying component of the duty ratio to control power exchange to and from the third electric device.