Synchronized Inverter Control for DC Bus Voltage Stability
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Solution Overview
Problem
Current systems for controlling electrical motors and generators require large DC bus capacitors to stabilize voltage, which increases size and cost, and struggles with voltage sag and swell during dynamic load changes.
Innovation Solution
Implementing a synchronized control system for load machines and generators, matching current regulator bandwidths and adjusting inductance values to reduce the size of the DC bus capacitor by minimizing energy storage needs, and using a parallel inverter scheme with coordinated voltage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large DC bus capacitors are used to stabilize voltage, then voltage stability is improved, but device size and cost increase
Solution Approach 1:
The control system performs preliminary synchronization of voltage commands before load transients occur. The controller pre-coordinates the inverters' voltage output based on predicted load changes, ensuring that voltage support is already in place when the transient occurs, thereby reducing the required capacitor size while maintaining stability
Solution Approach 2:
The system implements feedback control by continuously monitoring DC bus voltage and load conditions. The controller adjusts inverter voltage commands in real-time based on voltage deviations and load changes, enabling dynamic voltage stabilization that allows for smaller energy storage elements
2Volume of stationary object
If DC bus capacitor size is reduced to decrease device volume, then device complexity is reduced, but voltage sag and swell during dynamic load changes worsen
Solution Approach 1:
The controller synchronizes voltage commands from multiple inverters in advance of load transients. By pre-coordinating the voltage output based on predicted load changes, the system ensures immediate voltage support when transients occur, eliminating the need for large capacitors to handle voltage sags and swells
Solution Approach 2:
The patent replaces the mechanical/physical energy storage function of large DC bus capacitors with a control-based solution. The synchronized inverter control system actively manages voltage stability through coordinated voltage commands, substituting the passive energy storage approach with an active control approach that achieves the same stability function with smaller physical components
3Use of energy by moving object
If synchronized control with matched bandwidths is implemented, then energy storage requirements are reduced, but control system complexity increases
Solution Approach 1:
The system adjusts control parameters (current regulator bandwidths, inductance values) to achieve synchronization between inverters. By tuning these parameters, the control system coordinates voltage commands effectively, reducing the energy storage requirements while managing complexity through parameter optimization rather than complex control algorithms
Data Source
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AI summary
In an example embodiment, a controller includes a memory (336) having computer-readable instructions stored therein and a processor (332). The processor is configured to execute the computer-readable instructions to: determine a first set of inductance values for at least one load machine (380i-380n) and a second set of inductance values for a generator machine (300), determine a first set of gains for the at least one load machine (380) based on the first set of inductance values and a first regulator bandwidth, determine a second set of gains for the generator machine (300) based on the second set of inductance values and the first regulator bandwidth, and generate voltage commands for driving the at least one load machine (380) and the generator machine (300) based on at least the first and second sets of gains.