DC-DC Bus Balancing Circuit With Fewer Semiconductor Switches

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Solution Overview

Problem

Conventional uninterruptible power supplies (UPS) require an additional balancing bridge arm to balance direct current bus voltages, leading to increased system costs and reduced power density due to the higher number of semiconductor devices.

Innovation Solution

A DC-DC conversion circuit that includes a series connection of four switching transistors with antiparallel diodes, inductors connected to the battery electrodes, and switches to control the circuit's operation in charging, discharging, and balancing modes, effectively balancing direct current bus voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional balancing bridge arm is added to balance direct current bus voltages, then the voltage balancing function is improved, but the quantity of semiconductor devices increases and system cost increases

Engineering Contradiction:

Improvevoltage balancing capabilityVSAvoidquantity of semiconductor devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the DC-DC converter perform multiple functions: it can charge the battery, discharge the battery, and balance the direct current bus voltages. By integrating the balancing function into the existing converter circuit rather than adding a separate balancing bridge arm, the quantity of semiconductor devices is reduced while maintaining voltage balancing capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the balancing function with the existing DC-DC converter circuit. The converter is configured to operate in different modes (charging, discharging, balancing) by controlling the switching states of its components, thereby merging multiple functions into a single integrated circuit rather than using separate dedicated circuits for each function.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If an additional balancing bridge arm is added to balance direct current bus voltages, then the voltage balancing function is improved, but the system cost increases

Engineering Contradiction:

Improvevoltage balancing capabilityVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The DC-DC converter is designed to perform multiple functions including charging, discharging, and voltage balancing. This multi-functionality eliminates the need for a separate balancing bridge arm, reducing the total number of semiconductor devices required and thereby lowering system cost while maintaining voltage balancing capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If an additional balancing bridge arm is added to balance direct current bus voltages, then the voltage balancing function is improved, but the integrated power density of modules is reduced

Engineering Contradiction:

Improvevoltage balancing capabilityVSAvoidintegrated power density

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the balancing function into the existing DC-DC converter circuit, eliminating the need for a separate balancing bridge arm. This integration reduces the total component count and space requirements, thereby maintaining higher integrated power density while achieving voltage balancing capability.

Inventive Principle:

Principle #5Merging (Combining)

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 proposed solution allows the DC-DC conversion circuit to operate in multiple modes, thereby reducing the number of semiconductor devices, lowering system costs, and improving integrated power density while effectively balancing direct current bus voltages.

Implementation Method 1

the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor are respectively connected in antiparallel with a first diode, a second diode, a third diode, and a fourth diode

Methodology Applied

Scientific EffectDiode rectification: Diode

Implementation Method 2

a first inductor, one end of which is connected to a positive electrode of a battery, and a second end of which is connected to a first node between the first switching transistor and the second switching transistor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250125723A1Direct current(DC)-DC conversion circuits for balancing direct current buses

Publication Date: 2025.04.17 SANTAK ELECTRONICS SHENZHEN

AI summary

A direct current (DC)-DC conversion circuit for balancing direct current buses is provided, including: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor that are connected in series between direct current buses, and are respectively connected in antiparallel with a diode; a first inductor, one end of which is connected to a positive electrode of a battery, and a second end is connected to a first node; a second inductor, one end of which is connected to a negative electrode of the battery, and a second end of which is connected to a third node; a first switch, connected between the first inductor and the positive electrode of the battery or between the second inductor and the negative electrode of the battery; and a third switch and a third inductor that are connected in parallel, connected between a second node and a ground.