Micro-Blower Motor Bridge Control for Back-EMF Overvoltage Protection
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Solution Overview
Problem
Medical ventilators face significant electrical overvoltages during motor deceleration phases, which can damage components and reduce performance, with existing solutions like energy recovery circuits being complex and inefficient, and transient absorption diodes providing inadequate protection.
Innovation Solution
A control system for the motorized micro-blower in medical ventilators, featuring a transistor bridge circuit with three parallel transistor bridges, voltage regulation diodes, and additional protection components like Schottky diodes and capacitors to manage overvoltages and energy peaks during deceleration phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If energy recovery circuits are installed to recover braking energy, then energy efficiency is improved, but device complexity increases and implementation becomes complicated
Solution Approach 1:
The harmful back-EMF energy generated during motor deceleration is converted into a beneficial protective mechanism. The diode bridge circuit redirects this energy into a safe dissipation path, transforming what would be a damaging voltage spike into a controlled energy release that protects the power bus and connected components.
2Productivity
If the motor decelerates rapidly to match patient expiratory phases, then respiratory support accuracy is improved, but electrical surges increase causing component damage
Solution Approach 1:
The diode bridge circuit is pre-configured to provide anti-action against potential voltage spikes before they can damage components. During motor deceleration, the diode bridge immediately activates to redirect back-EMF energy, preemptively neutralizing the harmful electrical surges that would otherwise result from rapid motor slowing to match patient expiratory phases.
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
Effectively controls motor accelerations and decelerations while protecting sensitive components from electrical overvoltages, preventing component deterioration and ensuring reliable operation.
Implementation Method 1
a plurality of voltage regulation diodes arranged in parallel with the transistors to limit at least part of the overvoltages (i.e. voltage or energy peaks) of the motor during decelerations (i.e. braking or slowing down) of the motor
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a respiratory assistance device (100) comprising a micro-blower (2) with an electric motor (3), a motor control system (5), and a power supply (4) supplying power to the electric motor (3) and the control system (5) via a power bus (20). The control system (5) comprises a transistor bridge circuit (80), arranged between the power supply (4) and the electric motor (3), comprising three transistor bridges (90, 91, 92) arranged in parallel, each transistor bridge (90, 91, 92) connecting the bus (20) to the motor (3) and comprising a pair of transistors (T1-T6). A motor control circuit (100) controls at least the accelerations and decelerations of the motor (3) and is electrically connected to the motor (3) and the transistors (T1-T6). Voltage regulating diodes (D1-D6) are arranged in parallel with the transistors (T1-T6) to limit the overvoltages of the motor (3), during decelerations or braking of the motor (3).