Development of a Hysteresis Amplifier with an H-bridge Drive for Self-Sensing Magnetic Suspension

2000 ◽  
Vol 12 (3) ◽  
pp. 218-223 ◽  
Author(s):  
Takeshi Mizuno ◽  
◽  
Yuji Ishino
Keyword(s):  
Feedback Control ◽  
Magnetic Suspension ◽  
Switching Frequency ◽  
Switching Rate ◽  
Load Impedance ◽  
Current Comparator ◽  
Switching Times ◽  
Switching Signal ◽  
Hysteresis Control ◽  
A Current

A switching amplifier with an H-bridge drive was developed for self-sensing magnetic suspension. In this amplifier, switching times are controlled by a current comparator with a small hysteresis. The amplifier implemented with such hysteresis control has asynchronous characteristics so that the switching rate depends on the load impedance. When the hysteresis amplifier is used for magnetic suspension, the gap between the suspended object and the electromagnet can be estimated from the switching frequency. Since the Hbridge reverses the polarity of the voltage applied to the coil alternatively, the switching frequency is insensitive to the value of current command to the amplifier. The F/V conversion of the switching signal was used for feedback control with the result that self-sensing suspension was achieved.

A New Modulation Method Based on Current Hysteresis Control for Cascaded H-Bridge Inverter

2012 ◽  
Vol 588-589 ◽  
pp. 393-396
Author(s):  
Min Sheng Yang ◽  
Si Guo Zhu
Keyword(s):  
Pulse Generator ◽  
Control Method ◽  
Fast Response ◽  
Control Pulse ◽  
Modulation Method ◽  
Switching Frequency ◽  
Switching Losses ◽  
Current Limiting ◽  
Hysteresis Control ◽  
A Current

This paper puts forward a current hysteresis control method suitable for cascaded H-bridge inverter. It has the following characteristics : The control method is similar to unipolar SPWM modulation for a single H bridge.It is simple for pulse generator and can effectively reduce the switching losses; The phase-shifted control pulse for multi H bridges of a phase with current hysteresis control can be generated which is similar to the phase shift SPWM by dynamically adjusting the width of hysteresis to keep power device switching frequency constant; It retains fast response, internal current limiting and with good stability for current hysteresis control.At last, the experimental results verify the correctness of the proposed method.

scholarly journals Space vector PWM sequence and harmonic comparison for high power current source rectifier

2021 ◽  
Author(s):  
Nagaraja H. Chikkegowda
Keyword(s):  
High Power ◽  
Current Source ◽  
Switching Frequency ◽  
Space Vector Pwm ◽  
Vector Sequence ◽  
Space Vector ◽  
Switching Losses ◽  
Vector Sequences ◽  
Vector Modulation ◽  
A Current

The space vector PWM (SVPWM) schemes for high power current source drives normally produce low order harmonics due to low switching frequency. To provide a SVPWM with the best harmonic performance, different space vector sequences suitable for a current source rectifier (CSR) are investigated in this project. Details on how to achieve the waveform symmetries with minimum switching frequency for each sequence are discussed. A thorough comparison of the harmonic performance of different space vector sequences based on current source rectifier implementations is carried out. An optimum space vector modulation (SVM) method is proposed to achieve the best line current THD and reduced switching losses. The space vector sequence investigation has been verified in simulation and experimentally using a 10kVA GCT based CSR prototype.

A current-comparator-based system for on-site calibrations of high voltage PMU systems

2012 ◽  
Author(s):  
Eddy So ◽  
Rejean Arseneau ◽  
Yi-hua Tang ◽  
Gerard Stenbakken ◽  
Tom Nelson
Keyword(s):  
High Voltage ◽  
Current Comparator ◽  
A Current
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