Hybrid Electric HVDC Circuit Switching for Battery Overcharge Control
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Solution Overview
Problem
Existing hybrid electric propulsion systems face challenges in efficiently managing electrical power flow and voltage regulation during motoring and generation modes, leading to inefficiencies in system sizing, weight, and potential battery overcharging faults.
Innovation Solution
A conditionally regulated HVDC architecture that includes switchable circuits and a bi-directional DC-DC converter, controlled by a processor, to dynamically adjust power flow and voltage regulation based on operating modes, ensuring efficient power transfer and preventing battery overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage regulation is always applied during power flow between HVDC bus and electrical source, then battery overcharging is prevented, but system complexity and weight increase due to continuous DC-DC converter operation
Solution Approach 1:
The system dynamically switches between regulated and unregulated power flow modes based on operating conditions (motoring vs. generation mode). The DC-DC converter is conditionally engaged only when voltage regulation is needed, transforming the static voltage regulation approach into a dynamic one that adapts to real-time system state, thereby reducing unnecessary complexity while maintaining reliability when needed
Solution Approach 2:
Voltage regulation is applied locally and selectively only when required (during generation mode when battery charging occurs), rather than uniformly across all operating conditions. This localized application of regulation reduces overall system complexity and weight while maintaining the critical function of preventing battery overcharging during the specific conditions when it is needed
2Reliability
If DC-DC converter is always switched in to regulate power flow, then voltage regulation is maintained, but power transfer efficiency and response time during motoring mode deteriorate
Solution Approach 1:
The system employs periodic switching of the DC-DC converter based on operational cycles (motoring mode vs. generation mode). During motoring mode, the converter is switched out to enable efficient unregulated power transfer; during generation mode, it is switched in to provide necessary voltage regulation. This periodic engagement optimizes power transfer efficiency during motoring while maintaining voltage regulation during generation
Solution Approach 2:
Voltage regulation is applied partially rather than continuously - only during generation mode when the electrical source is charging and voltage control is critical. During motoring mode, full unregulated power transfer is permitted, providing excessive power transfer capability that improves efficiency and response time when the converter is disengaged
3Productivity
If switchable circuits are implemented to enable conditional regulation, then system efficiency improves through unregulated power flow, but device complexity increases due to additional switching components
Solution Approach 1:
The DC-DC converter is designed with multi-functionality, serving both as a power conversion device and a voltage regulation device. The same converter circuit handles both regulated power flow during generation mode and can be rapidly switched out for unregulated power flow during motoring mode, eliminating the need for separate dedicated circuits and reducing overall system complexity despite the switching capability
Solution Approach 2:
The patent merges the voltage regulation function and power flow control function into a single switchable DC-DC converter system. By combining these functions and using a unified switching mechanism, the system achieves efficient unregulated power transfer during motoring mode while maintaining voltage regulation during generation mode, without requiring entirely separate circuit systems that would increase complexity
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
The solution enables optimized system sizing, reduced weight, and enhanced safety by allowing unregulated power flow during motoring and regulated power flow during generation, while preventing battery overcharging, thus improving overall system efficiency and reliability.
Implementation Method 1
a bi-directional direct current to direct current (DC-DC) converter configured to regulate electrical power flowing between the HVDC bus and the HVDC electrical source
Implementation Method 2
the one or more electric motor/generators assume a generator function and extract mechanical power from the engine to provide electric power
Implementation Method 3
a motor drive system (MDS) including one or more electric motor/generators... is installed in an engine to assist the engine in peak propulsion demand moments
Data Source
AI summary
A method includes determining an operating mode of a hybrid electric propulsion system. The hybrid electric propulsion system includes a conditionally regulated high voltage direct current (HVDC) architecture. The conditionally regulated HVDC architecture includes a first switchable circuit formed between an HVDC bus, an HVDC electrical source, and a bi-directional direct current to direct current (DC-DC) converter configured to regulate electrical power flowing between the HVDC bus and the HVDC electrical source. The conditionally regulated HVDC architecture also includes a second switchable circuit formed between the HVDC bus and the HVDC electrical source. The method also includes configuring the conditionally regulated HVDC architecture based on the determined operating mode.