Half-Bridge Circuit with Voltage Divider for PWM Inverters

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Solution Overview

Problem

Existing power inverter technologies face inefficiencies due to complex control algorithms, additional circuit elements, and increased component count, which lead to higher losses and reduced reliability in generating multi-level PWM signals for DC to AC conversion.

Innovation Solution

A circuit topology with a passive input voltage divider and two half-bridges, utilizing bidirectional switches and capacitors to compensate middle node voltage, along with a simplified switching control scheme that reduces switching and Ohmic losses, allowing for autonomous operation without complex control algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complex control algorithms and additional circuit elements are used to generate multi-level PWM signals, then the PWM signal generation capability is improved, but the device complexity and component count increase

Engineering Contradiction:

Improvemulti-level PWM signal generation capabilityVSAvoidcircuit architecture complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The circuit is divided into two independent half-bridges, each capable of generating three-level PWM signals autonomously. This segmentation allows each half-bridge to operate with simplified control logic while collectively providing the full multi-level PWM output capability, thereby reducing overall device complexity without sacrificing adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each half-bridge circuit is designed to perform multiple functions: generating three-level PWM signals, providing galvanic isolation, and enabling bidirectional power flow. This multi-functionality eliminates the need for additional dedicated circuits, reducing component count while maintaining versatile multi-level PWM generation capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If additional circuit elements and complex control algorithms are implemented, then the PWM signal quality is improved, but the switching losses and Ohmic losses increase

Engineering Contradiction:

Improvevoltage and current control accuracyVSAvoidswitching and Ohmic losses

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The half-bridge circuits are designed to self-regulate their switching operations, with each bridge autonomously controlling its switches based on simple voltage comparison logic. This self-service mechanism eliminates the need for complex centralized control algorithms, reducing computational overhead and associated switching losses while maintaining accurate voltage and current control

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The circuit operates by changing the switching states of MOSFETs in each half-bridge based on the polarity of the output current and the desired voltage level. This parameter-based control approach simplifies the control logic to basic voltage and current threshold comparisons, reducing the complexity of control algorithms while maintaining precise control accuracy and minimizing switching losses

Inventive Principle:

Principle #35Parameter changes

3Reliability

If more active components are used to achieve reliable operation, then the reliability is improved, but the component count and device complexity increase

Engineering Contradiction:

Improveoperational reliabilityVSAvoidnumber of active components

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The circuit merges the functions of voltage generation, current control, and galvanic isolation into a single integrated half-bridge module. Each half-bridge combines multiple active components (MOSFETs, diodes, capacitors) into a unified structure that performs multiple critical functions simultaneously, reducing the total component count while enhancing reliability through functional integration

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The half-bridge circuit employs a composite structure combining MOSFETs for switching, diodes for freewheeling, and capacitors for voltage stabilization. This composite arrangement of different semiconductor devices and passive components creates a robust, reliable circuit that achieves high operational reliability without requiring an excessive number of individual components

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10541623B1Circuit with an input voltage divider and two half-bridges

Publication Date: 2020.01.21 INFINEON TECHNOLOGIES AG

AI summary

A circuit topology and switching scheme for a circuit that includes an input voltage divider configured to provide a divided voltage that may be approximately half of a supply voltage. The circuit also includes a switching circuit with a first half-bridge that includes a first switching node and a second half-bridge that includes a second switching node. One or more switches are configured to connect the divided voltage to the first switching node and the second switching node.