Stacked Half-Bridge Battery Charging With Switched-Capacitor Boosting
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Solution Overview
Problem
Conventional battery charging systems for high-voltage batteries require additional power converters for boosting and balancing, leading to increased cost, complexity, and space usage.
Innovation Solution
A battery charging system that incorporates an inverter, transformer, stacked half-bridge rectifier, and control circuitry to operate as a switched capacitor booster or balancer, eliminating the need for separate power converters by using a blocking capacitor as a flying capacitor to charge batteries from AC or DC sources with varying voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional boost converter and balancer power converter are added to charge high-voltage batteries, then charging capability and battery balancing are improved, but system complexity, cost, and device mass increase
Solution Approach 1:
The stacked half-bridge rectifier is designed to perform multiple functions: it can operate as a standard rectifier, as a boost converter for voltage matching, and as a balancer power converter for energy distribution between batteries. By integrating these functions into a single device, the system eliminates the need for separate boost converter and balancer power converter components, thereby reducing system complexity while maintaining full charging capability and battery balancing functionality
Solution Approach 2:
The invention merges the rectifier, boost converter, and balancer power converter into a single stacked half-bridge rectifier unit. The circuit topology combines the rectification bridges and balancer switches in a unified structure where shared components (capacitors, inductors, switches) serve multiple purposes simultaneously, eliminating redundant components and reducing overall system complexity
2Adaptability or versatility
If conventional boost converter and balancer power converter are added to charge high-voltage batteries, then charging capability and battery balancing are improved, but device mass and space usage increase
Solution Approach 1:
The stacked half-bridge rectifier serves as a multi-functional device that replaces the boost converter, balancer power converter, and traditional rectifier. By consolidating these functions into one device, the total mass of power conversion equipment is significantly reduced while maintaining full charging capability and battery balancing functionality
Solution Approach 2:
The invention merges multiple power conversion functions into a single unified device, eliminating redundant components. The shared capacitors, inductors, and switching devices reduce the total component count and overall device mass while providing boost conversion and battery balancing capabilities
3Adaptability or versatility
If conventional boost converter and balancer power converter are added to charge high-voltage batteries, then charging capability and battery balancing are improved, but system cost increases
Solution Approach 1:
The stacked half-bridge rectifier is designed as a universal power conversion device that can operate in multiple modes: standard rectification, boost conversion for voltage matching, and battery balancing. This multi-functionality eliminates the need for separate boost converter and balancer power converter purchases and installations, significantly reducing system cost while maintaining full charging capability
Solution Approach 2:
The invention merges multiple power conversion functions into a single unified device, eliminating redundant components. The shared capacitors, inductors, and switching devices reduce the total component count and overall system complexity while providing boost conversion and battery balancing capabilities
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 solution enables efficient charging and balancing of high-voltage batteries from lower voltage sources without additional converters, reducing system complexity and cost while improving efficiency through soft switching techniques.
Implementation Method 1
control circuitry that can selectively operate the one or more contactors and switching devices of the stacked half bridge rectifier as a switched capacitor booster using the blocking capacitor as a flying capacitor to charge the battery from the second DC source
Implementation Method 2
alternating between: a first switching state in which lower switches of the upper and lower half bridges of the rectifier are closed while upper switches of the upper and lower half bridges are opened to charge the blocking capacitor as a flying capacitor of the switched capacitor booster; and a second switching state in which upper switches of the upper and lower half bridges of the rectifier are closed to discharge the flying capacitor into the battery
Implementation Method 3
The frequency of alternating between the first switching state and the second switching state can be controlled to achieve soft switching using energy stored in an inductance that resonates with the flying capacitor. The inductance can include a leakage inductance of the transformer and/or a discrete inductor
Implementation Method 4
a transformer having a primary winding coupled to an output of the inverter and a secondary winding
Data Source
AI summary
A battery charging system can include a stacked half bridge rectifier having an upper half bridge (“UHB”) and a lower half bridge (“LHB”); a blocking capacitor and a winding coupled between a midpoint of the UHB and a midpoint of the LHB; a battery coupled between an upper terminal of the UHB and a lower terminal of the LHB; and control circuitry that can selectively operate the stacked half bridge rectifier as a switched capacitor converter using the blocking capacitor as a flying capacitor by alternating between: a first switching state in which lower switches of the UHB and LHB are closed while upper switches of the UHB and LHB are opened; and a second switching state in which upper switches of the UHB and LHB are closed; wherein the switched capacitor converter operates as a booster to charge the battery from a DC voltage lower than the battery voltage.