1, except that the former is configured as differential inputs (V IN+, and V IN -) instead of a single-ended input (V IN) and shutdown (SHDN). The current sensor ACPL-C79A shares all the key functional blocks of the ACPL-C87A as shown in Fig. The 1414 V PEAKmaximum working voltage specification per IEC/EN/DIN EN 6 ensures circuits on the low voltage side are not damaged by hazardous high voltages. These iso-amps have a double protection rating of 5000 V RMS/1 min per the UL 1577 safety standard. The ACPL-C87X family features a stretched SO-8 package that is 30% smaller than a DIP-8 package. Other options include ☐.5% (ACPL-C87B) and ☓% (ACPL-C870). The voltage sensor ACPL-C87A provides ☑% measurement accuracy. The output voltage, provided in differential mode for better common mode noise rejection, is proportional to input voltage with unity gain. The photodetector recovers the optical signal and converts it back to an electrical signal, which is decoded and filtered to reproduce an analog output signal. Because the transmitted signal is optical rather than electrical, it is immune to magnetic fields and electrical noise. This optical signal path provides the electrical insulation barrier. The bit stream is then transmitted across the optical coupling pair consisting of an LED and a photodetector. Internal block diagram of the ACPL-C87A.įirst the isolation amplifier senses the input voltage (single-ended analog signal) and converts it to a digital bit stream. Optical Isolation AmplifiersĪs an example, functional blocks of the ACPL-C87A are shown in Fig. These voltage, current and temperature information from the iso-amps are collected by the microcontroller, which uses the data to calculate the feedback values and output signals needed to provide effective control and fault management in the power converters. In this application, the voltage sensor must linearly and accurately measure temperature and send it across the isolation barrier thus providing safety insulation. The isolated voltage sensor ACPL-C87A can also be used in isolated temperature sensing designs. This voltage and current sensing is performed even in the presence of high switching noise. The ACPL-C79A works with a shunt resistor to provide accurate current measurement. 1 (iso-amp) ACPL-C87A works as a precision voltage sensor together with a resistive divider consists of R1 and R2, monitoring the DC bus voltage. With the use of appropriate power switching devices, signal isolators, and control circuits an inverter’s ac output can be set to any required voltage and frequency. Block diagram of power converter in a motor drive. IGBTs form the heart of the inverter they must operate at a high frequency and must be able to withstand high voltages. The inverter converts the dc bus voltage to ac power at a variable frequency to drive the motor. 1 shows a typical inverter in an ac motor drive. Test Saturation Voltage to Achieve High Efficiency #2įig.Test Saturation Voltage to Achieve High Efficiency #1.AC Power Testing Presents Many Challenges and Concerns.EMC Poses Challenge for Automotive Electronics.Test Equipment Must Keep Pace with New High Power Semiconductor Developments.Characterizing High Power Semiconductors Requires New Technologies.The active vibration isolation experimental platform is further developed, and the experimental results validate the effectiveness of the designed multi-DOF active vibration isolation scheme. The loop shaping technology is used to avoid the current drift and achieve high accuracy vibration isolation over the designed bandwidth. The robust vibration isolation controller is presented considering the control uncertainty caused by the voice coil clearance and the low frequency drift of accelerometers. Non-contact voice coil actuators are designed as the driving unit of active vibration isolation. This paper thus proposes a multi-degree of freedom (DOF) active vibration isolation approach for the ultra-stable optical reference cavity to satisfy the stringent micro-vibration requirement. The realization of such a strict micro-vibration requirement over broadband frequencies is still technically challenging under complex space disturbances in the order of milli-g (mg). Inevitably, the micro-vibration level in the order of micro-g (μg) is required for ultra-stable optical reference cavity of space optical clocks. Space optical clocks with frequency instability better than 1 × 10 − 15 are increasingly demanded for PNT (positioning, navigation, and timing) and space physical science.
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