Power Converter with Bidirectional PWM Regulators for Transmitter Efficiency

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Solution Overview

Problem

Existing power converters for radio transmitters, particularly those using polar modulators, face inefficiencies due to the presence of a linear regulator that dissipates energy and reduces overall system efficiency, especially when dealing with variable load resistances and high dynamics in amplitude modulation.

Innovation Solution

The implementation of a power converter that combines a step-down and step-up PWM regulator, allowing for dynamic voltage adjustment and energy recovery, along with a control method that calculates the duty cycle based on real-time resistance measurements, enabling efficient operation with variable loads and high dynamics without dissipating energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a linear regulator is added in cascade with a step-down PWM regulator to follow quicker dynamics and reduce switching noise, then the noise and spurious components are reduced, but the overall efficiency of the system decreases due to energy dissipation

Engineering Contradiction:
Improvenoise and spurious componentsVSAvoidenergy dissipation
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent removes the linear regulator from the system entirely, extracting the harmful energy-dissipating component while maintaining the PWM regulator for noise reduction. The step-down PWM regulator operates alone without the cascaded linear regulator, eliminating the efficiency penalty while preserving the benefits of PWM switching.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent discards the excess energy that would normally be dissipated by the linear regulator by implementing a recovery mechanism. The step-up PWM regulator captures and recycles the excess energy from the power amplifier supply, converting it back to useful power rather than letting it be wasted as heat in a linear regulator.

Inventive Principle:
Principle #34Discarding and recovering

2Loss of energy

If a step-down PWM regulator is used to vary supply voltage for high efficiency, then efficiency is improved, but the regulator cannot handle variable load resistances and high dynamics effectively

Engineering Contradiction:
ImproveefficiencyVSAvoidhandling variable loads and high dynamics
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent makes the power converter fully dynamic by using two PWM regulators with adjustable duty cycles that can respond in real-time to varying load conditions. The step-down and step-up regulators work in coordination with variable duty cycles, allowing the system to adapt dynamically to changing power amplifier supply requirements and variable load resistances, rather than being constrained by fixed operating points.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal power converter that can handle multiple operating conditions and variable loads through the combination of step-down and step-up PWM regulators. This multi-functional system can operate efficiently across a wide range of power levels and load impedances, making it adaptable to different power amplifier configurations and modulation dynamics without requiring separate circuits for each condition.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If the resistance of the final stage at supply port is assumed constant for simplified control, then control calculation is simplified, but the system cannot accommodate unmatched or variable loads

Engineering Contradiction:
Improvecontrol calculation complexityVSAvoidaccommodation of variable loads
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback control where the actual supply voltage and current are monitored, and the duty cycles of both PWM regulators are adjusted based on real-time measurements. This closed-loop approach allows the system to accommodate variable loads and unmatched conditions by continuously adapting to actual operating conditions rather than relying on fixed resistance assumptions, while keeping control manageable through iterative duty cycle adjustment.

Inventive Principle:
Principle #23Feedback

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 solution achieves high efficiency and dynamic performance by effectively managing voltage and energy flow, reducing noise and spurious components, and accommodating unmatched or variable loads, while maintaining high efficiency and minimizing energy loss.

Implementation Method 1

The implementation of a power converter that combines a step-down and step-up PWM regulator, allowing for dynamic voltage adjustment and energy recovery

Methodology Applied
Scientific EffectPulse Width Modulation:

Implementation Method 2

The implementation of a power converter that combines a step-down and step-up PWM regulator, allowing for dynamic voltage adjustment and energy recovery

Methodology Applied
Scientific EffectEnergy Recovery:

Implementation Method 3

a control method that calculates the duty cycle based on real-time resistance measurements, enabling efficient operation with variable loads and high dynamics

Methodology Applied
Scientific EffectElectrical Resistance Measurement: Electrical Resistance

Data Source

PatentEP1894289B1High efficiency power converter, and modulator and transmitter using it
Publication Date: 2009.11.04 SELEX COMM SPA
  • EP1894289B1 patent drawingFigure 1~2
  • EP1894289B1 patent drawingFigure 3A~3B
  • EP1894289B1 patent drawingFigure 4~5

AI summary

A power converter is described adapted to be connected to an electrical power source, in particular a voltage source (Vcc) , and intended to receive at the input a control signal (A(t)) for the conversion, including a first regulator circuit (L1, C1, M1, D1) of the pulse width modulation step-down type and an energy recovery- circuit for managing a bidirectional flow of energy from the source to the load and from the load to the source; such an energy recovery circuit may advantageously be implemented using a second regulator circuit (L2, M2, D2) of the pulse width modulation step-up type.