Transformer-Coupled Regenerative Braking for Energy Recovery
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Solution Overview
Problem
Conventional regenerative braking systems dissipate back EMF as heat, leading to high brake resistor sizes and power dissipation, with sudden braking that can be detrimental to motor systems, and lack efficient energy conversion and storage.
Innovation Solution
The system operates in pulse braking and resonance regenerative modes, using a controller with H-bridge networks, PWM signals, and transformers to convert braking torque into regenerative power, storing energy and powering auxiliary systems, with a configurable duty cycle and threshold-based switching to manage DC link voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional regenerative braking systems dissipate back EMF as heat through brake resistors, then energy is recovered during braking, but brake resistor size and power dissipation become excessively large
Solution Approach 1:
The patent replaces the conventional mechanical/thermal dissipation system (brake resistors converting electrical energy to heat) with an electrical system (transformers and rectifiers converting electrical energy to electrical energy). The transformer-coupled regenerative braking system transfers back EMF energy through electromagnetic induction to charge the DC link, eliminating the need for large brake resistors and their associated thermal dissipation infrastructure.
Solution Approach 2:
The patent changes the operational parameters of the braking system by introducing configurable duty cycles for the H-bridge switches and transformers. By adjusting the duty cycle, the system optimizes the transfer of regenerative energy to the DC link, maximizing energy recovery efficiency while minimizing the required brake resistor size. This parameter control enables flexible adaptation to different braking conditions and energy storage capacities.
2Speed
If conventional regenerative braking systems use brake resistors, then braking function is achieved, but sudden braking occurs that can be detrimental to motor systems
Solution Approach 1:
The patent introduces dynamic control through configurable duty cycles for the H-bridge switches and transformers. The system can adjust the braking torque progressively rather than abruptly, allowing smooth energy transfer to the DC link. This dynamic control prevents sudden braking shocks to the motor system while maintaining effective speed reduction, thereby protecting motor reliability during regenerative braking operations.
3Loss of energy
If conventional regenerative braking systems lack efficient energy conversion, then braking energy is captured, but energy conversion and storage efficiency is low
Solution Approach 1:
The patent replaces inefficient thermal dissipation with efficient electrical-to-electrical energy conversion using transformers and rectifiers. The transformer-coupled system transfers back EMF energy through electromagnetic induction with high efficiency, converting it directly to charge the DC link capacitor. This eliminates the energy loss inherent in thermal dissipation and achieves superior energy conversion efficiency for regenerative braking.
Solution Approach 2:
The patent implements feedback control by monitoring the DC link voltage and adjusting the duty cycle of the H-bridge switches and transformers accordingly. When the DC link reaches its voltage threshold, the control system modulates the energy transfer rate to prevent overcharging while maximizing energy recovery. This feedback mechanism optimizes the balance between energy capture and storage capacity, enhancing overall energy conversion efficiency.
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
This approach reduces brake resistor size, improves responsiveness and control, and efficiently transforms motor braking torque into regenerative power for energy storage and auxiliary use, enhancing the efficiency and fuel consumption of electric drives.
Implementation Method 1
controlling a first brake drive switch and a second brake drive switch in a sequential fashion which allows current to flow to a transformer for regeneration
Implementation Method 2
a brake resistor coupled to the DC link
Data Source
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AI summary
Provided are embodiments for a braking system, where the system includes a controller, a motor coupled to an H-bridge network, a DC link coupled to the motor, and an electrical braking system (100) electrically coupled to the motor. The electrical braking system (100) includes a sense circuit configured to sense a condition of the DC link, a brake resistor coupled to the DC link, a drive circuit coupled to the sense circuit, and a transformer for regeneration. Also, provided are embodiments of a method for operating an efficient regenerative resonance electrical braking system (100).