Energy Storage Module Current Control for Stable Buck Conversion

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Solution Overview

Problem

Existing battery cell packs face challenges in maintaining well-defined output voltage and current parameters due to internal and external non-idealities, particularly in buck-type power converters like multi-level inverters, where achieving stable closed-loop responses is difficult.

Innovation Solution

Implementing a circuit with a transfer function comprising a first gain component with a higher than first-order low-pass response and a second gain component, along with a unit gain response, to control the module current and ensure stable operation of energy storage devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional control methodologies are used in buck-type power converters, then the system structure remains simple, but the output voltage and current parameters become unstable due to internal and external non-idealities

Engineering Contradiction:
Improvestability of output voltage and currentVSAvoidcomplexity of control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop control system that continuously monitors the actual output voltage and current, compares them with reference values, and adjusts the switching signals accordingly. This feedback mechanism compensates for internal non-idealities (such as component tolerances) and external disturbances (such as load variations), ensuring stable output parameters despite the added control complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts control parameters including duty cycle, switching frequency, and gain values based on operating conditions. By changing these parameters in real-time, the system maintains optimal performance and stability across different load conditions and temperature ranges, addressing the reliability challenge without requiring overly complex hardware

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional control is applied to multi-level inverters, then the device structure remains straightforward, but achieving well-defined output independent of non-idealities becomes difficult

Engineering Contradiction:
Improveprecision of output voltage and currentVSAvoidcomplexity of control circuitry
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs multiple feedback loops that independently monitor and control different output parameters. This multi-variable feedback approach ensures that each output parameter (voltage and current) maintains precise values despite variations in component characteristics or operating conditions, achieving manufacturing precision through active compensation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary calibration and parameter adjustment during startup and mode transitions to preemptively compensate for expected non-idealities. By preparing the control parameters in advance based on predicted operating conditions, the system achieves precise output without requiring complex real-time adjustments

Inventive Principle:
Principle #10Preliminary action

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 ensures stable and well-defined output voltage and current parameters in energy storage systems, effectively addressing non-idealities and enhancing the performance of buck-type power converters.

Implementation Method 1

converting, via an inductor, a difference between the input voltage and the counter voltage to a module current

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4641875A1Current control methodologies for energy storage devices
Publication Date: 2025.10.29 INSTAGRID GMBH
  • EP4641875A1 patent drawingFigure 1A
  • EP4641875A1 patent drawingFigure 1B
  • EP4641875A1 patent drawingFigure 1C

AI summary

Systems, methods and software products for operating circuit with energy storage module (ESM). The methods comprising: providing, at input port, an input voltage (IV); providing, via PWM, counter voltage (CV2); converting, via inductor, a difference between IV and CV2 to module current (MC) which charges or discharges ESM; providing reference waveform signal (RWS); generating error signal (ES) by combining MC measurement with RWS; applying, to ES, a transfer function (TF) to obtain correction signal (CS1); generating control signal (CS2) by combining CS1 with IV measurement; and using CS2 to govern MC's instantaneous value. TF may comprise: first gain component (FGC) having a higher than first-order low-pass response with a first corner frequency (CF), and a first low-frequency (DC) gain value; a second gain component acting parallelly to FGC and having a second low-frequency (DC) gain value; and a unit gain response providing a gain between TF's input and output.