MEMS Rectifier Circuit for Low-Loss AC Power Conversion

Solution Overview

Problem

Existing rectifiers using diodes for AC voltage rectification suffer from significant power losses and heat generation issues, particularly at mains input voltages, which limit efficiency and lead to premature failure, and require complex cooling systems.

Innovation Solution

The use of MEMS switches as current valves in rectifier circuits, which offer low contact resistance and low power consumption, enabling high efficiency and reduced failure probability, along with the integration of diodes in parallel to protect against surge pulses, and a switching controller to manage switching based on voltage and harmonic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If diodes are used for AC voltage rectification, then the rectifier structure is simple, but power losses are significant and heat generation is high

Engineering Contradiction:

Improverectifier structureVSAvoidpower losses

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent replaces semiconductor diodes with MEMS (micro-electro-mechanical) switches in the rectifier circuit. This substitution eliminates the inherent power losses and heat generation associated with diode forward voltage drops, achieving significantly lower power consumption and reduced thermal management requirements while maintaining the rectifier's structural simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the switching elements from semiconductor-based fixed characteristics to MEMS-based variable characteristics. The MEMS switches exhibit near-zero contact resistance when closed and near-infinite resistance when open, enabling operation with minimal power loss and allowing adaptation to different voltage conditions without the fixed voltage drop limitations of diodes.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If diodes are used for AC voltage rectification, then the rectifier structure is simple, but heat generation is high requiring complex cooling systems

Engineering Contradiction:

Improverectifier structureVSAvoidheat generation

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The patent replaces semiconductor diodes with MEMS (micro-electro-mechanical) switches in the rectifier circuit. This substitution eliminates the inherent power losses and heat generation associated with diode forward voltage drops, achieving significantly lower power consumption and reduced thermal management requirements while maintaining the rectifier's structural simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If transistors are used to replace diodes, then efficiency can be improved, but cost increases and reliability decreases

Engineering Contradiction:

ImproveefficiencyVSAvoidsurge-proof capability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent replaces semiconductor diodes with MEMS (micro-electro-mechanical) switches in the rectifier circuit. This substitution eliminates the inherent power losses and heat generation associated with diode forward voltage drops, achieving significantly lower power consumption and reduced thermal management requirements while maintaining the rectifier's structural simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates surge protection circuitry and design features that protect the MEMS switches from voltage spikes and transient conditions. By implementing protective measures in advance, the system maintains high reliability and surge-proof capability while benefiting from the efficiency advantages of MEMS technology.

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

This approach results in highly efficient, compact, and cost-effective rectifiers with reduced cooling requirements, capable of operating at higher ambient temperatures and minimizing energy losses, thereby enhancing reliability and efficiency.

Implementation Method 1

The switching controller (60) is designed to drive the MEMS switches (S1, S2, S3, S4) to switch and open

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

the rectifier circuit comprises diodes (D1, D2, D3, D4) connected in parallel with the MEMS switches (S1, S2, S3, S4)

Methodology Applied

Scientific EffectDiode conduction: Diode

Data Source

PatentUS12027991B2Rectifier and power supply device

Publication Date: 2024.07.02 ROBERT BOSCH GMBH

AI summary

Various embodiments of the teachings herein include a rectifier. The rectifier may include: a rectifier circuit formed with current valves with microelectromechanical systems (MEMS) switches; and a switching controller driving the MEMS switches to switch and open. The switching controller opens the MEMS switches when a voltage feeding the rectifier falls below a minimum distance from a zero voltage.