Bi-directional DC/DC Converter Topology for Bipolar Systems
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Solution Overview
Problem
Existing DC/DC converters for bipolar or midpoint grounded systems are complex and costly due to the need for independent controllers for positive and negative sections, and they lack efficient mechanisms for balancing and fault detection.
Innovation Solution
A bi-directional DC/DC converter topology using a pair of inductors and active switches with diodes, allowing energy transfer between two midpoint-connected DC circuits, featuring a single controller for both sections, automatic reset, and self-balancing capabilities, with optional energy storage components for enhanced balancing and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If four active switches are used in the DC/DC converter circuit, then power transfer capability between bipolar DC circuits is achieved, but device complexity and gating circuit cost increase
Solution Approach 1:
The patent combines multiple functions into fewer components. The single-switch configuration merges the functions of power transfer, voltage conversion, and control that would traditionally require four separate switches. The capacitor serves multiple purposes including voltage balancing, energy storage, and isolation between the high-voltage and low-voltage sides, reducing overall circuit complexity while maintaining power transfer capability.
Solution Approach 2:
The single active switch and capacitor in the patent perform multiple functions simultaneously. The switch handles bidirectional power flow control, while the capacitor provides voltage balancing, energy storage, and galvanic isolation. This multi-functionality reduces the number of components needed compared to traditional four-switch configurations, directly addressing the complexity issue while preserving power transfer capability.
2Measurement precision
If independent controllers are used for positive and negative sections, then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the control of both positive and negative sections into a single controller. The capacitor naturally balances the voltages between the two sections, eliminating the need for independent controllers. The single controller manages the single active switch, while the passive capacitor handles the balancing function that would otherwise require additional active control circuits, thereby reducing complexity while maintaining control precision.
Solution Approach 2:
The capacitor in the circuit automatically performs voltage balancing between the positive and negative sections without requiring external control. This self-balancing mechanism eliminates the need for complex independent controllers, as the system uses the inherent properties of the capacitor to maintain voltage equilibrium, reducing controller complexity while preserving control precision.
3Power
If traditional DC/DC converter topology is used, then power transfer is achieved, but fault detection capability and automatic balancing are insufficient
Solution Approach 1:
The patent incorporates voltage sensing and control mechanisms that provide feedback about the system state. The single controller monitors the voltage across the capacitor and adjusts the switch operation accordingly to maintain proper balancing. This feedback mechanism enables automatic detection of imbalance conditions and adjusts operation to correct them, improving fault detection capability while maintaining power transfer function.
Solution Approach 2:
The capacitor automatically performs voltage balancing between the high-voltage and low-voltage sides through its inherent energy storage capability. This self-balancing function improves reliability by automatically correcting voltage imbalances without requiring external intervention or complex detection circuits, while the single controller can detect abnormal conditions through voltage sensing.
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 topology reduces complexity and cost by using a single controller, self-regulates currents, automatically balances DC-links, and enables quicker fault detection and reduced short-circuit currents, improving efficiency and reliability in bipolar DC systems.
Implementation Method 1
a storage configuration, wherein energy is transferred from one of the buses and stored in the inductors; and a release configuration, wherein energy is released from the inductors and transferred to the other of the buses
Data Source
AI summary
A method for transferring power between two DC circuits, each circuit being bipolar or connected at the midpoint thereof, involves: coupling the high voltage bus across a pair of inductors, arranged in parallel; coupling the low voltage bus across the pair of inductors; coupling the high voltage bus, the low voltage bus and the inductors by active switches and diodes, to provide for: (i) a storage configuration, wherein energy is transferred from one of the buses and stored in the inductors; and (ii) a release configuration, wherein energy is released from the inductors and transferred to the other of the buses.