Active Clamp Rectifier Circuit for Voltage Ringing Recovery

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Solution Overview

Problem

Power supply systems with traditional clamping methods experience voltage ringing issues, leading to increased voltage stress on rectifier devices and inefficiencies due to power dissipation in passive clamping components, which can result in electromagnetic interference and reduced operational efficiency.

Innovation Solution

The implementation of an active clamping circuit with a clamping diode, capacitor, and flyback converter that stores and delivers energy to the output, reducing voltage stress on rectifier devices and minimizing power loss by using a clamping current path circuit to provide a clamping current associated with the clamping voltage, thereby conserving power and reducing voltage ringing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional passive clamping methods are used, then voltage ringing is suppressed, but power loss increases and rectifier device voltage stress increases

Engineering Contradiction:

Improvevoltage ringingVSAvoidpower loss

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent converts the harmful voltage ringing energy into useful output power by using a flyback converter to transfer the clamping energy from the clamping capacitor to the output. The energy that would normally be dissipated as heat in passive clamping components is instead recovered and delivered to the load, eliminating power loss while suppressing voltage ringing.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces a clamping capacitor as an intermediary energy storage element between the rectifier and the output. This capacitor captures the voltage ringing energy and serves as a buffer, allowing the energy to be transferred to the output through the flyback converter rather than being dissipated directly, thus reducing power loss while maintaining voltage ringing suppression.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If traditional passive clamping methods are used, then voltage ringing is suppressed, but rectifier device voltage stress increases

Engineering Contradiction:

Improvevoltage ringingVSAvoidvoltage stress on rectifier devices

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The clamping capacitor acts as an intermediary that decouples the voltage ringing suppression function from the rectifier devices. By placing the capacitor in parallel with the rectifier output, it absorbs voltage spikes and ringing, preventing these high-voltage transients from stressing the rectifier devices while still achieving effective voltage ringing suppression.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The clamping capacitor provides beforehand cushioning by being pre-charged and positioned to absorb voltage ringing before it can propagate to and stress the rectifier devices. The capacitor serves as a protective buffer that cushions against voltage transients, reducing voltage stress on rectifier components.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If higher-rated rectifier devices are used to handle voltage stress, then reliability improves, but device complexity and cost increase

Engineering Contradiction:

Improverectifier device reliabilityVSAvoidrectifier device rating requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The clamping capacitor provides beforehand cushioning that protects rectifier devices from voltage ringing and transients. This protective buffer allows the use of lower-rated rectifier devices since the capacitor absorbs the voltage stress before it reaches the rectifiers, thereby maintaining reliability while reducing device complexity and cost requirements.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 active clamping circuit effectively reduces voltage ringing, lowers voltage drop across rectifier devices, and enhances the efficiency of the power supply system by conserving power and minimizing power loss, allowing for the use of lower-rated rectifier devices and reducing electromagnetic interference.

Implementation Method 1

a transformer for delivering an output voltage on the secondary winding of a transformer from a square-wave input voltage applied by the switches to the primary winding of the transformer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a clamping capacitor arranged between a cathode of the clamping diode and an output to store a charge that provides a clamping voltage

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

a flyback converter that provides a clamping current from the clamping capacitor to the output

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20240275293A1Power supply system with active clamping

Publication Date: 2024.08.15 TEXAS INSTRUMENTS INC

AI summary

One example includes a circuit. The circuit includes a rectifier having a rectifier output and an active clamp circuit having a control input, a clamp circuit input, and a clamp circuit output. The clamp circuit input can be coupled to the rectifier output and the clamp circuit output can be coupled to an output of the circuit. The circuit also includes a drive circuit having a drive output coupled to the control input.