Hybrid Powertrain Rectifier Control for Variable DC Bus Loads
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Solution Overview
Problem
Existing hybrid powertrain systems rely heavily on large batteries, which are weight and cost prohibitive, and cannot efficiently accommodate rapidly changing load demands, particularly in applications like UAVs and electric vehicles.
Innovation Solution
A hybrid powertrain system with a prime mover, generator/motor, rectifier, and energy storage device, where the rectifier converts AC to DC power and adjusts current flow based on load changes, allowing the prime mover to operate efficiently and independently of rotational speed, reducing battery size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If batteries are used as the energy source in a powertrain system, then the system can supply large amounts of power and rapidly meet variable power demand, but the gravimetric energy density is very low which limits payload capacities and flight times
Solution Approach 1:
The patent combines a battery system with a generator system to form a hybrid powertrain. The battery provides rapid power response for variable demand while the generator supplies sustained power for extended operation. This merging allows the system to achieve both high power capability and extended endurance without requiring a single large, heavy battery.
Solution Approach 2:
The generator/motor in the hybrid powertrain serves multiple functions: it can operate as a generator to recharge the battery, as a motor to directly drive the propeller, or idle to maintain battery charge. This multi-functionality allows the system to flexibly manage power sources based on immediate needs, reducing the required battery capacity and weight while maintaining power supply capabilities.
2Weight of moving object
If a battery is combined with an electric generator and combustion engine in a hybrid powertrain system, then the battery capacity can be reduced, but the system complexity increases
Solution Approach 1:
The control system dynamically manages the hybrid powertrain by continuously monitoring battery state of charge, power demand, and generator/motor operating conditions. It automatically adjusts the generator/motor operation mode (generator, motor, or idle) and regulates power flow between components based on real-time conditions, optimizing battery usage and reducing its required capacity.
Solution Approach 2:
The generator/motor acts as an intermediary component that mediates between the combustion engine and the battery. It can convert mechanical energy from the engine to electrical energy for battery charging, or convert electrical energy from the battery to mechanical energy for direct propulsion, thereby reducing the battery's burden and size requirements.
3Duration of action of moving object
If the generator operates to produce electrical power output that recharges the battery, then the battery can meet power demands for extended periods, but frequent charging and discharging reduces battery lifetime
Solution Approach 1:
The control system implements periodic charging cycles where the generator/motor operates in generator mode to recharge the battery during periods of lower power demand, then switches to motor mode during high demand periods. This periodic action pattern prevents continuous deep discharge cycles, extending battery lifetime while maintaining extended operational capability.
Solution Approach 2:
The system performs preliminary charging actions by having the generator/motor charge the battery in advance during low-demand periods, preparing the battery for subsequent high-demand operations. This preliminary action reduces the frequency and depth of discharge cycles, thereby extending battery life while ensuring power availability when needed.
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 system reduces battery size and weight, improves efficiency, and accommodates varying loads, extending vehicle range and endurance while reducing production costs and mechanical vibrations.
Implementation Method 1
an electrical generator/motor, where the generator/motor can operate in both directions to optimize energy use
Implementation Method 2
a prime mover combusts a fuel and produces a rotational output
Data Source
AI summary
A hybrid powertrain system and method includes a prime mover driving a generator/motor to produce an AC power output. The AC power output is applied to a rectifier which is controlled to transform the applied AC power to DC power to supply a DC Power bus at a selected voltage and current. An energy storage device is also connected to the DC power bus and the current flow between the energy storage device and the DC power bus is monitored and compared to preselected values and the results of that comparison are used to alter the operation of the rectifier to increase or decrease, as needed, the current provided to the DC power bus as electrical loads on the DC power bus change.