Detection and Mitigation of Electrostatic Pull-in Instability in MEMS Parallel Plate Actuators

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 000495-000514
Author(s):  
Colin Stevens ◽  
Robert Dean
Keyword(s):  
Range Of Motion ◽  
Parallel Plate ◽  
High Speed ◽  
Vibration Isolation ◽  
Voltage Source ◽  
Inrush Current ◽  
Stable Range ◽  
Precise Control ◽  
Simulink Model ◽  
Operational Range

Electrostatic MEMS actuators are used in a wide variety of applications including micro-machined gyroscopes, high speed mechanical switches, variable capacitors, and vibration isolation devices. MEMS parallel plate actuators (PPAs) are simple to realize, yet complex nonlinear variable capacitors. If a DC voltage is applied in attempt to move the proof mass greater than 1/3 of the electrode rest gap distance, the device becomes unstable and the electrodes snap into contact. Most research into this pull-in phenomena is devoted to extending the operational range of motion past the 1/3 instability point. This usually involves the addition of complex external electronics. Many applications, however, only require that the actuator remain out of the pull-in region, and do not require an extended stable range of motion. If detection of the pull-in event is all that is required, then simpler solutions can be realized, minimizing the requirements on the driving signal. Once pull-in is reached, the velocity of the movable plate increases rapidly until the plates make contact. The decreasing distance causes a proportional increase in capacitance. To maintain a constant voltage across the plates, an inrush of current must flow into the actuator in response to the increased capacitance. This paper presents a method for detecting the inrush current using a transimpedance amplifier circuit to convert the current to a measurable voltage. Once pull-in is detected, the PPA is electrically shutdown to prevent damage to the actuator or the voltage source, thus mitigating pull-in. A simulation of the expected results was performed using a Simulink model for the actuator structure predicting the expected range of inrush current. This result was then verified using a silicon micro-machined PPA connected to the detection/mitigation circuit on a PCB. The experimental results follow closely with the simulation allowing precise control in mitigating the pull-in event.

scholarly journals Damping of vertical and horizontal transverse vibrations in the bridge span structures

2018 ◽  
Vol 216 ◽  
pp. 01015
Author(s):  
Darya Provornaya ◽  
Sergey Glushkov ◽  
Leonid Solovyev
Keyword(s):  
High Speed ◽  
Vibration Isolation ◽  
Seismic Protection ◽  
Rolling Stock ◽  
Railway Bridge ◽  
Vibration Damper ◽  
Dynamic Vibration ◽  
Bridge Span ◽  
Transverse Vibrations ◽  
Dynamic Damping

The paper considers the issues of vibration isolation of railway bridge units on high-speed lines and seismic protection using dynamic vibration dampers. The purpose of the research is to justify the efficiency of damping the dynamic vibrations of the bridge supports with seismic insulating support parts. The research methodology involves building mathematical models of the systems under consideration and their numerical analysis. The methods of structural mechanics and dynamics of structures were used for solving the assigned tasks. The basic mathematical dependences of the vibration system with two seismic masses were developed. The rolling stock was represented by concentrated forces moving along the span structure. As a result, a new scheme for dynamic damping of vibration of the bridge supports was proposed according to which the span structure used as the dynamic vibration damper has an additional fastening on a rigid abutment.

scholarly journals Plugging Braking of Two-PMSM Drive in Subway Applications with Fault -Tolerant Operation

2016 ◽  
Vol 12 (1) ◽  
pp. 1-11
Author(s):  
Adel Obed ◽  
Ali Abdulabbas ◽  
Ahmed Chasib
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Fault Tolerant ◽  
Permanent Magnet Synchronous Motor ◽  
Voltage Source ◽  
Braking System ◽  
Simulink Model ◽  
Braking Torque ◽  
Subway Train ◽  
Electric Traction

The Permanent Magnet Synchronous Motor (PMSM) is commonly used as traction motors in the electric traction applications such as in subway train. The subway train is better transport vehicle due to its advantages of security, economic, health and friendly with nature. Braking is defined as removal of the kinetic energy stored in moving parts of machine. The plugging braking is the best braking offered and has the shortest time to stop. The subway train is a heavy machine and has a very high moment of inertia requiring a high braking torque to stop. The plugging braking is an effective method to provide a fast stop to the train. In this paper plugging braking system of the PMSM used in the subway train in normal and fault-tolerant operation is made. The model of the PMSM, three-phase Voltage Source Inverter (VSI) controlled using Space Vector Pulse Width Modulation technique (SVPWM), Field Oriented Control method (FOC) for independent control of two identical PMSMs and fault-tolerant operation is presented. Simulink model of the plugging braking system of PMSM in normal and fault tolerant operation is proposed using Matlab/Simulink software. Simulation results for different cases are given.

scholarly journals Numerical Differential Protection of Power Transformer using Innovative Algorithm

2019 ◽  
Vol 8 (5S3) ◽  
pp. 438-446
Keyword(s):  
Power Transformer ◽  
Algorithm Design ◽  
Point Of View ◽  
Inrush Current ◽  
Current Transformers ◽  
Simulink Model ◽  
Internal Fault ◽  
Safety And Reliability ◽  
Operating Current ◽  
Primary Current

This paper presents a new innovative algorithm for Numerical Differential Relay design of transformer. Fault information is critical for operating and maintaining power networks. This algorithm provides accurate performance for transformer by which is independent of system conditions such as: External fault, Inrush current, CT saturation. Locating transformer faults quickly and accurately is very important for economy, safety and reliability point of view. Both fault-detection and protection indices are derived by using Numerical Differential Relay algorithm design of transformer. The embedded based differential and operating current measurement device is called numerical differential relay is among the most important development in the field of instantaneous fault operation. Numerical relay provides measurement of differential current and operating current at power transformer above 5MVA in substation. Simulation studies are carried out using MATLAB Software show that the proposed scheme provides a high accuracy and fast relay response in internal fault conditions. Current transformers form an important part of protective systems. Ideal Current Transformers (CTs) are expected to reflect the primary current faithfully on the secondary side. Under conditions the CT saturates, and hence it cannot reproduce the primary current faithfully. This paper deals with simulation methods for determining CT performance under different factor. A Simulink model has been developed to observe CT response under steady state w.r.t Burden, Turns ratio, Asymmetrical current, Hysteresis conditions. Thus, it is now possible to evaluate the CT performance under these factors

scholarly journals A New Optimal DTC Switching Strategy for Open-End Windings Induction Machine using Dual Inverter

2021 ◽  
Vol 12 (3) ◽  
pp. 1405
Author(s):  
Nabilah Aisyah ◽  
Maaspaliza Azri ◽  
Auzani Jidin ◽  
M. Z. Aihsan ◽  
MHN Talib
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Dynamic Condition ◽  
Dynamic Control ◽  
Direct Torque Control ◽  
Torque Control ◽  
Dynamic Responses ◽  
Voltage Source ◽  
Optimal Switching ◽  
Stator Flux

<span>Since the early 1980s, fast torque dynamic control has been a subject of research in AC drives. To achieve superior torque dynamic control, two major techniques are used, namely Field Oriented Control (FOC) and Direct Torque Control (DTC), spurred on by rapid advances in embedded computing systems. Both approaches employ the space vector modulation (SVM) technique to perform the voltage source inverter into over modulation region for producing the fastest torque dynamic response. However, the motor current tends to increase beyond its limit (which can damage the power switches) during the torque dynamic condition, due to inappropriate flux level (i.e. at rated stator flux). Moreover, the torque dynamic response will be slower, particularly at high speed operations since the increase of stator flux will produce negative torque slopes more often. The proposed research aims to formulate an optimal switching modulator and produce the fastest torque dynamic response. In formulating the optimal switching modulator, the effects of selecting different voltage vectors on torque dynamic responses will be investigated. With greater number of voltage vectors offered in dual inverters, the identification of the most optimal voltage vectors for producing the fastest torque dynamic responses will be carried out based on the investigation. The main benefit of the proposed strategy is that it provides superior fast torque dynamic response which is the main requirements for many AC drive applications, e.g. traction drives, electric transportations and vehicles.</span>

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