Differential sampling of AC waveforms based on a programmable Josephson voltage standard using a high-precision sampler

A high-precision sampler, Fluke 8588A multimeter in the sampling mode, was utilised to perform differential sampling of AC waveforms with a programmable Josephson voltage standard. The systematic error on the differential sampling, induced by the inherent voltage-response characteristics and built-in low-pass filter of the sampler, was estimated. Experimental results and numerical simulations revealed that the sampler could be used for reliable differential sampling of AC waveforms at frequencies up to several kilohertz, with an appropriate number of the voltage steps per the waveform period, when the input bandwidth was set to 3 MHz. In addition, the sampler was compared to an integrating sampler, Keysight 3458A, now widely used for differential sampling. At 62.5 Hz, a key frequency in the future on-site key comparison of the differential sampling on AC voltage, the difference in RMS-amplitude values obtained by the differential sampling using the two different samplers is approximately 150 nV/V due to the systematic error caused by the limited bandwidth of 150~kHz for the integrating sampler.

Error factors of AC-DC conversion circuits accuracy

Voltage standard source is an important basic instrument in the electrical measurement and testing field, and it has important guarantee significance for many industries. AC voltage standard source is based on AC-DC conversion technology to achieve output function of high precision AC voltage. In order to get a better effect of AC-DC conversion, the three factors—operational amplifier, resistance and diode—that have a greater impact on the accuracy of the rectifier output were taken the research object, and their impacts on the circuit error were analyzed respectively. The output result was compared with the output of full wave precision rectification circuit under ideal state, and the scheme of reducing error in the precision rectifier circuit was summarized, which provides a reference for improving the accuracy of AC-DC conversion in the design of full wave rectifier circuit.

Optimasi Battery Charging pada Pendingin Minuman dengan Sumber Solar Cell untuk Beban Peltier Menggunakan Buckboost Converter

Currently, many electronic devices use the energy source from the solar cell which is stored in a battery. The battery is a portable, rechargeable power source. Solar energy is very suitable when converted to electrical energy because the amount of sunlight is infinite even though there is a period of time between sunrise and sunset. Converting solar energy to electrical energy requires a solar cell. One method that can be done is using the buck boost converter method with solar cell sources to create a battery charging control system. The Buck Boost Converter method was chosen because it can stabilize the output voltage from the solar cell when the weather is uncertain. If the light intensity of the sunlight is dim, the output voltage of the panel will also be low, then the converter will be in boost mode to increase the voltage level, on the other hand, if the light intensity of the panel output voltage will also be high, the converter will be in buck mode to lower the voltage level. The output voltage of this control system is maintained according to the battery charging voltage standard, which is 14 volts DC.

Active Power Management for PV Systems under High Penetration Scenario

Although PV systems are one of the most widely used alternatives as a renewable energy source due to their well-known advantages, there are significant challenges to address related to voltage fluctuations and reverse power flow caused by high PV penetration scenarios. As a potential solution to this problem, an active power management strategy is proposed in this work using a residential cluster as a benchmark. The proposed strategy is analyzed and experimentally verified, offering a simple way to reduce the voltage fluctuations by regulating the active power delivered by the PV system, achieving also relevant functionalities for the system, such as the regulation of the DC bus voltage, maximum power point tracking (MPPT), synchronization with the grid voltage, detection of high penetration conditions, and a simple strategy for the main controller with an effective performance. The proposal system shows satisfactory results being able to maintain grid voltage fluctuations within the voltage standard specifications.