ABSTRACT
The rotational speed standard device that can carry loads is the key device for calibrating passive rotational speed sensors. The rotor of the passive rotational speed sensor is connected to the rotor of the standard speed device through a coupling, and the standard reference speed is provided by the standard device. Due to the rotor eccentricity, the unbalanced force of the rotor occurs, and it can not only affect the rotational speed accuracy but can also damage the mechanical bearings of the standard speed device. To solve this issue, a method for suppressing the unbalanced force of the speed standard device based on an active magnetic bearing (AMB) force compensation system is proposed. First, the overall structure of the system is briefly introduced. Then, the force feedback control system model with the AMB as the force actuator is established, and a PI controller is designed to achieve the disturbed force control. Finally, a semi-physical simulation experimental platform is built to verify the effectiveness of the proposed method. The experimental results show that the AMB force compensation system can reduce 84.4%, 81.6%, and 79.8% of the unbalanced vibration force at the frequency of 30 Hz, 90 Hz, and 150 Hz, respectively.
ABSTRACT
To develop a standard defibrillation energy source which can output monophasic and biphasic de-fibrillation impulses and can display standard energy values. The storage capacitor was charged by single-end flyback transformator and discharged through the H bridge composed of insulated gate bipolar transistor (IGBT). Impulse voltage and current were collected by divider while discharging, and the energy value was calculated by STM32. The en-ergy value and waveform were displayed through the control module. The energy source could output both monophsic and biphasic waveforms, and the accuracy of displayed value was higher than ±2% or ±1 J. The standard defibrillation energy source can be used as standard device for defibrillator analyzer, and the metrological trace-ability system of defibrillation energy may come to be completed.
