Multi-source power transfer via current setpoint regulation
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Solution Overview
Problem
Multi-source electrical power systems face power interruptions and disturbances in power quality, such as voltage dips and circulating currents, when transferring power between sources due to uncontrolled load shifting and oscillations.
Innovation Solution
A method and system for transferring power between two sources in a multi-source electrical power system, where the output voltage of the second power source is regulated to match the bus voltage, and the current setpoint is adjusted to zero amperes or a current ramp, allowing for controlled power delivery and smooth transitions, reducing oscillations and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voltage setpoint of pickup source is set higher than running source voltage to achieve power transfer, then power delivery transfer is enabled, but power oscillations and voltage dips occur
Solution Approach 1:
The patent changes the control parameter from voltage setpoint to current setpoint. The current regulator controls the pickup source's current output to match the running source's current, preventing oscillations while enabling smooth power transfer. This parameter transformation resolves the contradiction between enabling power transfer and maintaining stability.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the running source's current and using it as the setpoint for the pickup source's current regulator. This closed-loop feedback mechanism ensures the pickup source mirrors the running source's behavior, eliminating uncontrolled oscillations during transfer.
2Loss of energy
If complex algorithms are used to adjust internal voltage setpoints among regulators, then circulating current is reduced, but load shifts become uncontrolled and oscillations increase
Solution Approach 1:
The patent extracts the voltage regulation function from the power transfer control, leaving only current control for transfer management. By separating these functions, the system uses simple current matching for transfer control while voltage regulation handles circulating current independently, resolving the contradiction between reducing circulating current and maintaining load control.
3Adaptability or versatility
If power sources are coupled to electrical bus for power transfer, then power delivery switching is enabled, but voltage dips and spikes occur
Solution Approach 1:
The patent applies preliminary action by pre-regulating the pickup source's voltage to match the bus voltage before coupling, and pre-setting the current setpoint based on the running source's current. This preliminary preparation prevents voltage dips and spikes during the actual coupling operation.
Solution Approach 2:
The current regulator acts as an intermediary between the pickup source and the electrical bus, controlling the pickup source's current contribution to match the running source's current. This intermediary control prevents abrupt current changes that cause voltage dips and spikes during power source switching.
Data Source
AI summary
Systems and methods for transferring power delivery between power sources to an electrical bus are provided. More particularly, a multi-source electrical power system can include an electrical bus having at least two power sources that each can be selectively coupled to the electrical bus, for instance, via contactors. At least one of the power sources can include a unidirectional or bidirectional power converter. The electrical power system can further include a control system configured to control the power output (e.g., the output voltage and the output current) of the power converter to provide no break power transfer of power delivery to the electrical bus between the first and second power sources. In example embodiments, the no break power transfer can be achieved by regulating the output current of a power source to a fixed current value and/or by using a virtual resistance programmed into a voltage regulator.