DC Bus Converter Control for Real-Time Voltage Stability

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Solution Overview

Problem

Current power systems face challenges in timely and continuous control of direct current (DC) bus voltage, leading to excessive fluctuations that can damage the system, as existing methods rely on open-loop conditions and lack effective real-time adjustments to maintain voltage within acceptable ranges.

Innovation Solution

A power system with a controller that adjusts output power and current based on real-time voltage and power thresholds, using upper and lower voltage limit loops and a power loop to determine target current values, ensuring the DC bus voltage remains within safe limits by prioritizing voltage control when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If open-loop voltage adjustment is used, then the control method is simple, but the voltage control is discontinuous and prone to sudden changes

Engineering Contradiction:
Improvecontrol method complexityVSAvoidvoltage control stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a closed-loop feedback control mechanism where the controller continuously monitors the DC bus voltage and dynamically adjusts the converter's output power based on the voltage deviation from the threshold. This feedback loop ensures continuous voltage regulation, preventing the discontinuous control and sudden voltage changes inherent in open-loop methods while maintaining system reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If real-time voltage control is implemented, then the voltage remains within safe range, but the control system complexity increases

Engineering Contradiction:
Improvevoltage safetyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs dynamic control by continuously adjusting the converter's output power in real-time based on the monitored DC bus voltage. The controller dynamically modifies the power output to maintain voltage within the safe range, implementing adaptive voltage regulation that responds to changing system conditions rather than using fixed control parameters.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The closed-loop feedback mechanism continuously monitors voltage and adjusts control actions accordingly, enabling real-time voltage safety assurance while managing system complexity through intelligent control algorithms that prioritize voltage stability.

Inventive Principle:
Principle #23Feedback

3Productivity

If power modulation is prioritized, then the power output meets grid requirements, but the bus voltage may exceed limits

Engineering Contradiction:
Improvepower output efficiencyVSAvoidbus voltage fluctuation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The feedback control mechanism continuously monitors bus voltage and dynamically adjusts power modulation to prevent voltage from exceeding limits. When voltage approaches the threshold, the controller automatically reduces power output to maintain voltage within safe ranges, balancing power delivery requirements with voltage stability constraints.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically balances power output and voltage control by continuously adapting the converter's operation. The controller adjusts power modulation in real-time based on voltage conditions, enabling the system to meet grid power requirements while preventing harmful voltage fluctuations through dynamic response to changing operating conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4068550B1Power system and control method
Publication Date: 2024.09.25 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4068550B1 patent drawingFigure 1
  • EP4068550B1 patent drawingFigure 2A
  • EP4068550B1 patent drawingFigure 2B

AI summary

Embodiments of this application provide a power system and a control method. The power system includes a controller. The controller is configured to adjust an output current of a first converter to a first current value based on a voltage of a direct current bus and a voltage threshold, where a difference between an adjusted voltage of the direct current bus and the voltage threshold is less than a difference between the unadjusted voltage of the direct current bus and the voltage threshold. The controller is further configured to adjust the output current of the first converter to a second current value based on output power of the first converter and a power threshold, where a difference between adjusted output power of the first converter and the power threshold is less than a difference between the unadjusted output power of the first converter and the power threshold. The controller is further configured to adjust the output current of the first converter based on the first current value and the second current value. In this technical solution, the controller may adjust the output current of the converter in real time based on the first current value and the second current value, so as to adjust output power supplied to a power grid or a load and control a voltage of a bus not to exceed the voltage threshold. In this way, a direct current bus is stably controlled.