Genset Load Sharing via Digital PI Control

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Solution Overview

Problem

Existing power systems with multiple generator sets (gensets) face challenges in precise load sharing, particularly in distributing real and reactive power efficiently, often relying on separate control systems and analog methods that require calibration and are prone to instability.

Innovation Solution

A networked power system utilizing Standard Proportional Integral (PI) controller algorithms and load sharing controllers connected via networks like Ethernet or CAN, which determine average set loads, generate power errors, and apply offsets to achieve balanced load distribution among gensets, enabling precise control without manual calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate control systems (engine speed governor and AVR) are used for real and reactive power control, then real power and reactive power can be controlled independently, but the system complexity increases and calibration becomes more difficult

Engineering Contradiction:
Improveindependent control capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the separate control systems for real power (engine speed governor) and reactive power (AVR) into a unified digital control platform. The load sharing controller integrates both control functions, allowing real and reactive power to be managed through a single coordinated system rather than independent analog systems, thereby reducing overall complexity while maintaining independent control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical control systems (analog governors and AVRs with mechanical linkages) with digital control systems. The load sharing controller uses digital signal processing and software-based control algorithms to replace mechanical sensing and actuation mechanisms, eliminating the need for physical calibration adjustments while maintaining precise control over real and reactive power output.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If analog load share systems are used with bidirectional analog lines, then load sharing can be achieved between gensets, but the system requires manual calibration and is prone to instability

Engineering Contradiction:
Improveload sharing capabilityVSAvoidsystem stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces the analog electrical signaling system with digital communication protocols. Instead of using bidirectional analog lines that require manual calibration and are susceptible to drift and noise, the system employs digital communication between load sharing controllers to exchange load information and coordination signals, eliminating calibration requirements and improving stability through precise digital signal transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements enhanced feedback mechanisms where load sharing controllers continuously monitor actual load output, compare it with target values, and automatically adjust control parameters. This closed-loop digital feedback system replaces the open-loop or poorly regulated analog systems, providing automatic correction of deviations and maintaining stable load sharing without manual intervention.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If traditional analog control systems are used, then load sharing can be achieved, but precise control over varying operating conditions is difficult and manual calibration is required

Engineering Contradiction:
Improveload sharing operationVSAvoidload sharing precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces analog measurement and control mechanisms with digital sensors and digital signal processing. Precision analog-to-digital converters accurately capture electrical parameters, and digital control algorithms process this data with high precision, enabling accurate load measurement and control across varying operating conditions without the drift and tolerance issues inherent in analog systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamic control capabilities where the load sharing controller can automatically adapt control parameters in real-time based on changing operating conditions. The system dynamically adjusts governor and AVR setpoints, communication frequencies, and control gains to maintain optimal performance across different load levels and operating scenarios, replacing static analog control with adaptive digital control.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3167530B1Genset power control in power systems
Publication Date: 2019.09.04 CUMMINS POWER GENERATION IP INC
  • EP3167530B1 patent drawingFigure 1
  • EP3167530B1 patent drawingFigure 2
  • EP3167530B1 patent drawingFigure 3

AI summary

A method includes determining an average set load corresponding to a plurality of gensets of a power system, generating a power error based on the determined average set load and a set load of a genset of the plurality, generating a first offset based on a function of the power error and a predetermined factor, determining a secondary offset, generating a final offset based on the first offset and the secondary offset, generating a final reference value based on a nominal reference and the final offset, and applying the final reference value to obtain proportional load sharing between the plurality of gensets.