Regenerative Braking Circuit Synchronization Control
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Solution Overview
Problem
Regenerative braking systems face inefficiencies due to low power factor and high total harmonic distortion, which degrade energy efficiency and require bulky filters, increasing costs and complexity.
Innovation Solution
A regenerative braking system with a circuit that includes a switchable device, edge detector, and control circuitry to synchronize current transfer with AC mains, maintaining high power factor and low total harmonic distortion through voltage and current control loops, allowing for efficient energy recovery without large filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is implemented without synchronization control, then energy recovery is achieved, but power factor deteriorates and total harmonic distortion increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the AC mains voltage waveform through an edge detector and using this information to synchronize the switching of power electronic devices. The controller adjusts the switching timing based on the detected zero-crossing points, creating a closed-loop system that maintains synchronization between the regenerative braking operation and the AC mains, thereby achieving both energy recovery and acceptable power factor without requiring bulky passive filters
Solution Approach 2:
The patent changes the operating parameters of the power electronic switching devices dynamically by synchronizing their switching instants with the AC mains voltage waveform. The switching duty cycle and timing are adjusted based on the detected AC mains phase, transforming the operation from fixed timing to adaptive timing that follows the AC waveform, thus improving power factor and reducing harmonics during regenerative braking
2Object-generated harmful factors
If bulky filters are added to improve power factor and reduce harmonic distortion, then power quality improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/passive filtering approach with an active electronic control approach. Instead of using bulky passive filters (inductors, capacitors, resistors) to correct power factor and reduce harmonics, the system uses actively controlled power electronic switching devices synchronized to the AC mains waveform. This substitution of passive mechanical filtering with active electronic control achieves the same power quality improvement while dramatically reducing system complexity, size, and cost
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 achieves high power factor (>0.99) and low total harmonic distortion (<3%) during both normal and regenerative braking operations, enhancing energy efficiency and reducing costs by eliminating the need for bulky filters.
Implementation Method 1
Kinetic energy stored as inertial motion can be applied to a motor, which acts like a generator during regenerative braking operation to convert the kinetic energy into electricity
Data Source
AI summary
A circuit for delivering electrical energy to an AC mains connection is disclosed. The circuit includes a voltage source and a switch connected between the voltage source and the AC mains connection. The switch operates to transfer current from the voltage source to the AC mains. The circuit further includes a controller to control the switch. The controller operates to generate a simulated signal that represents a waveform of the AC mains without any distortion present on the waveform of the AC mains.