Active Equalizer Circuit With Shared Transformer Drive
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Solution Overview
Problem
Conventional active equalizer circuits for battery packs are costly and voluminous due to the use of numerous MOSFET switches and isolated drivers.
Innovation Solution
The proposed active equalizer circuit reduces costs and volume by using a driving transformer with shared secondary windings and a multi-port converter that eliminates the need for isolated drivers, with each battery cell requiring only one switching transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional active equalizer circuits use a large number of MOSFET switches and isolated drivers for each battery cell, then the equalization function can be achieved, but the cost and volume of the circuit increase significantly
Solution Approach 1:
The patent merges multiple isolated driver circuits into a single unified driver circuit that controls multiple MOSFET switches. The driving transformer uses a primary winding connected to the unified driver and multiple secondary windings connected to individual MOSFETs, consolidating what would otherwise be separate driver modules into one integrated unit, thereby reducing overall circuit volume.
Solution Approach 2:
The driving transformer serves multiple functions simultaneously: it provides galvanic isolation between the primary and secondary sides, steps down the voltage from the primary winding to appropriate levels for MOSFET gate驱动, and provides multiple secondary windings to drive multiple MOSFETs in parallel. This multi-functional design eliminates the need for separate isolated driver circuits for each MOSFET.
2Reliability
If conventional active equalizer circuits use a large number of MOSFET switches and isolated drivers for each battery cell, then the equalization function can be achieved, but the cost of the circuit increases significantly
Solution Approach 1:
The patent merges multiple isolated driver circuits into a single unified driver circuit that controls multiple MOSFET switches. The driving transformer uses a primary winding connected to the unified driver and multiple secondary windings connected to individual MOSFETs, consolidating what would otherwise be separate driver modules into one integrated unit, thereby reducing overall circuit volume.
Solution Approach 2:
The driving transformer serves multiple functions simultaneously: it provides galvanic isolation between the primary and secondary sides, steps down the voltage from the primary winding to appropriate levels for MOSFET gate驱动, and provides multiple secondary windings to drive multiple MOSFETs in parallel. This multi-functional design eliminates the need for separate isolated driver circuits for each MOSFET.
3Adaptability or versatility
If each battery cell requires multiple components (MOSFET, isolated driver, transformer winding), then individual cell control is achieved, but the overall circuit complexity increases
Solution Approach 1:
The patent segments the control function at the MOSFET level (each battery cell has its own MOSFET for individual control) while consolidating the driver function at the circuit level (a single unified driver controls multiple MOSFETs through the transformer). This segmentation allows individual cell control to be maintained while reducing overall circuit complexity by eliminating redundant driver circuits.
Solution Approach 2:
The driving transformer acts as an intermediary device that bridges the unified driver circuit and multiple MOSFET switches. It receives a single control signal from the unified driver, transforms and distributes it to multiple MOSFET gates through its secondary windings, thereby enabling individual cell control without requiring multiple isolated drivers.
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 design significantly reduces the volume and cost of the active equalizer circuit while maintaining efficient battery equalization, thereby improving the available capacity and cycle life of the battery pack.
Implementation Method 1
a driving transformer comprising a first primary winding and a plurality of first secondary windings, with each of the first secondary windings being coupled to a control terminal of a corresponding switching transistor
Implementation Method 2
an equalizing transformer comprises a second primary winding and a plurality of second secondary windings, output terminals of the bridge converter are coupled respectively to the first primary winding and the second primary windings
Data Source
AI summary
Embodiments of the present disclosure provide an active equalizer circuit, a battery management system, and a power supply system. The active equalizer circuit comprises a plurality of switching transistors, a driving transformer, a multi-port converter, a buck converter, and a microcontroller. Each of the switching transistors is coupled to a battery cell in the series battery pack on a one-to-one basis. The multi-port converter comprises an equalizing transformer and a bridge converter. The microcontroller is configured to output a first control signal to the buck converter, to facilitate the buck converter to transform an output voltage of the series battery pack and output the transformed output voltage to the bridge converter, and output a second control signal to the bridge converter, to control an operation state of the bridge converter.