Regenerative Power Controller for Overvoltage Protection
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Solution Overview
Problem
Power generation and distribution systems in aircraft and electric vehicles face challenges in managing transient overvoltage events, particularly at reduced speeds, where existing solutions like resistors are heavy and inefficient, and current control systems fail to regulate overvoltage effectively.
Innovation Solution
A controller system that computes power factor and ac current magnitude from dc bus voltage and load current signals, generating gating signals to convert excess electrical energy into mechanical energy by adjusting the power factor and switching to motoring mode when regenerative power exceeds thresholds, thereby stabilizing voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistors are used to dissipate excess electrical energy during braking, then overvoltage can be managed, but the system weight increases significantly
Solution Approach 1:
The patent converts the harmful excess electrical energy during braking into beneficial mechanical energy that can be stored and reused. The motor acts as a generator during regenerative braking, converting electrical energy back to mechanical form, which is then stored in a flywheel or other energy storage device. This eliminates the need for heavy resistive dissipation while recovering useful energy.
Solution Approach 2:
The system dynamically changes the operating parameters of the motor, switching between motor mode and generator mode based on operational conditions. During regenerative braking, the motor operates as a generator with adjusted speed and torque parameters to optimize energy recovery while maintaining overvoltage protection.
2Weight of moving object
If a controller system is used to convert excess electrical energy to mechanical energy, then system weight is reduced, but the control complexity increases
Solution Approach 1:
The motor serves multiple functions: it acts as a motor during propulsion, as a generator during regenerative braking, and as an energy conversion device for storing mechanical energy. This multi-functionality reduces the need for separate components while managing control complexity through integrated control strategies.
Solution Approach 2:
The controller implements feedback control by continuously monitoring electrical parameters (voltage, current, power) and mechanical parameters (speed, torque) to dynamically adjust the motor's operating mode. This feedback mechanism enables automatic switching between motor and generator modes while maintaining system stability and optimizing energy recovery.
3Reliability
If existing control configurations are used for managing overvoltage, then control is effective at near 100% rated speed, but the system fails to control overvoltage at reduced speeds like 70%
Solution Approach 1:
The control system dynamically adapts its parameters based on the operating speed. At reduced speeds, the controller adjusts the power factor and ac current magnitude computations to maintain effective overvoltage control. The system transitions smoothly between different operating regimes, ensuring consistent performance across the full speed range from 70% to 100% rated speed.
Solution Approach 2:
The controller modifies control parameters such as power factor, current magnitude, and switching frequencies based on the operating speed. At 70% rated speed, the controller adjusts these parameters to maintain optimal regenerative braking performance and overvoltage protection, whereas fixed parameter systems fail at reduced speeds.
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 controller system effectively manages transient overvoltage events at both 100% and 70% rated speeds, maintaining stable voltage levels and reducing the need for heavy resistors by converting excess energy into mechanical power, enhancing system efficiency and performance.
Implementation Method 1
a controller system that computes power factor and ac current magnitude from dc bus voltage and load current signals, generating gating signals to convert excess electrical energy into mechanical energy
Data Source
AI summary
Properly managing surges of regenerative power is needed in systems where power is generated and distributed to mechanical and electrical loads to protect them from overvoltage. A controller provides protection against excess regenerative power when these systems operate at a wide range of speeds. Controller functions and control methods for overvoltage protection may include an added control loop for detecting an overvoltage condition, calculating a power factor and generating a gating signal to transition the controller into a motoring mode that converts the excess regenerative power into mechanical power.