Single Phase Permanent Magnet Generator Control for State of Charge Balance

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Solution Overview

Problem

High voltage DC power systems with multiple permanent magnet generators face challenges in balancing the state of charge among high energy storage devices, as existing systems lack the ability to independently adjust power levels without additional dedicated converters, leading to potential imbalances during peak load operations.

Innovation Solution

The system employs single phase permanent magnet generators with control windings and asymmetric H-bridges, connected to a generator control unit that monitors state of charge through state of charge modules and adjusts control currents to balance energy storage devices by altering output voltage, eliminating the need for dedicated DC-DC converters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple permanent magnet generators are used in parallel to support peak power requirements, then the power capacity is improved, but the state of charge imbalance among energy storage devices worsens due to inability to independently control each generator

Engineering Contradiction:
Improvepower capacityVSAvoidstate of charge balance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The system segments the power generation control by providing individual control circuits for each permanent magnet generator. Each control circuit independently monitors the state of charge of associated energy storage devices and adjusts the generator's output accordingly, enabling granular control to prevent charge imbalance while maintaining overall power capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control circuits dynamically adjust operational parameters (such as duty cycle in PWM control) of each permanent magnet generator based on real-time state of charge measurements. By changing these control parameters, the system optimizes power distribution to maintain charge balance across all energy storage devices while supporting peak power demands.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If dedicated DC-DC converters are added to each generator to enable independent control, then the state of charge balance is improved, but the device complexity and cost worsen

Engineering Contradiction:
Improvestate of charge balanceVSAvoidconverter quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control circuits perform multiple functions: they rectify the AC output from permanent magnet generators, regulate DC voltage, monitor state of charge of energy storage devices, and control power distribution. By combining these functions into single control circuits rather than using separate dedicated converters for each function, the system achieves charge balance without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the control functions of multiple generators into a coordinated control architecture where control circuits share common monitoring resources and coordinate their output. This consolidation approach enables independent control of each generator while avoiding the need for completely separate control systems, thereby reducing overall complexity compared to having fully independent DC-DC converters for each generator.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables independent charging or discharging of each high energy storage device, effectively rebalancing the system and maintaining efficient power distribution during peak loads without additional converters, enhancing system stability and efficiency.

Implementation Method 1

synchronous permanent magnet generators are frequently utilized in this type of application

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

each of the single phase permanent magnet generators includes a control winding configured to at least partially control an output voltage of the single phase permanent magnet generator

Methodology Applied
Scientific EffectElectromagnetic control: Electromagnet

Data Source

PatentEP3255755B1High voltage power generating system
Publication Date: 2022.05.04 HAMILTON SUNDSTRAND CORP
  • EP3255755B1 patent drawingFigure 1
  • EP3255755B1 patent drawingFigure 2
  • EP3255755B1 patent drawingFigure 3

AI summary

A power system architecture includes a prime mover, a plurality of single phase permanent magnet generators (212) mechanically coupled to the prime mover (210), a DC power bus (230) including a plurality of DC power storage components (232), each of the DC energy storage components being electrically connected to at least one of the single phase permanent magnet generators, a plurality of state of charge calculators (234), each of the state of charge calculators being connected to one of the DC energy storage component and being communicatively coupled to a generator control unit (250), and wherein the generator control unit is configured to independently control each of the single phase permanent magnet generators.