Resonant Switched Capacitor Balancer Circuit for Soft Switching

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Solution Overview

Problem

Switching losses in switched capacitor circuits are significant due to voltages across the switch and current flowing through it, especially when operating at high frequencies.

Innovation Solution

Implement a resonant switched capacitor converter with a resonant circuit and a control method that enables zero-voltage switching (ZVS) and zero-current switching (ZCS) to reduce switching losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If switching frequency is increased to improve power conversion speed, then productivity is improved, but switching losses increase due to voltages across the switch and current flowing through it

Engineering Contradiction:
Improvepower conversion speedVSAvoidswitching losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by using resonant circuits to pre-charge or pre-discharge capacitor banks before switching operations. The resonant circuit prepares the voltage and current conditions in advance, ensuring that switches operate under zero-voltage or zero-current conditions, thereby eliminating switching losses while maintaining high switching frequency for improved productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the operating parameters of the switching circuit by utilizing resonant frequency relationships between inductors and capacitors. By tuning the resonant circuit parameters (inductance and capacitance values), the system achieves soft switching conditions where voltage and current are simultaneously minimized at switching instants, resolving the contradiction between high switching frequency and low switching losses

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional switching is used to simplify the circuit, then device complexity is reduced, but switching losses are significant due to voltage and current overlap

Engineering Contradiction:
Improvecircuit simplicityVSAvoidswitching losses
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent introduces resonant circuits as intermediary elements between the power switches and capacitor banks. These resonant circuits act as mediators that transform the switching process by creating oscillating current paths, enabling zero-voltage switching conditions without requiring complex multi-stage switching sequences, thus maintaining relative circuit simplicity while dramatically reducing switching losses

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution significantly reduces switching losses and increases efficiency by minimizing voltage and current transitions during switching operations.

Implementation Method 1

The SCC may include a resonant circuit including an inductor

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a resonant circuit including an inductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3846329B1DC balancer circuit with zvs
Publication Date: 2025.08.06 SOLAREDGE TECH LTD
  • EP3846329B1 patent drawingFigure 1A
  • EP3846329B1 patent drawingFigure 1B
  • EP3846329B1 patent drawingFigure 1C

AI summary

Disclosed herein are systems and/or methods for operation of a switched capacitor converter (SCC). The SCC may include a resonant circuit including an inductor. Aspects of the disclosure include methods for controlling the SCC switches (e.g., modulation methods) to decrease switching losses associated with operating the converter and to increase efficiency of the SCC. According to some aspects, a control method may be used to switch converter switches under zero-voltage conditions. According to some aspects, a control method may be used to switch converter switches under zero-current conditions.