Virtual Energy Storage: Converting an AC Drive to a Smart Load

Abstract

This paper proposes a new Smart-Load concept using AC drives. The concept is based on a secondary control layer coordinated with the network and the load to provide active power support. The general Smart-Load concept is developed and synthesized for its practical implementation in network power-frequency support applications. A multi power-frequency droop line is proposed. The final idea is applied to a fan load powered by an AC drive based on an induction motor and a two level voltage source converter. Experimental results show that a full power-frequency response can be achieved by the Smart-Load within 2s of the network frequency deviation.

Adaptive active and reactive power control strategy for virtual synchronous generator

“…With the increase in value of the regulator coefficient K iq , the undamped system will have a higher steady-state error, but a low value of the regulator coefficient K iq leads to a better step response with reduced steady-state error. Also, the inverse Laplace transform of Equation ( 5) is expressed in Equation ( 11) As per Equation ( 11), Figure 6 shows the step response of PCC voltage and the delay time t dÀu , response settling time t sÀu , and rise time t rÀu can be calculated as in Equation (12).…”

“…Furthermore, a better perspective on the parameters design principle is obtained by small-signal analysis, as mentioned in the literature. [12][13][14] Literature studies in 15 showed that a 1% increase/decrease in frequency causes a 6% to 12% decrease/ increase in reactive power as it has a negative slope in the visual representation of reactive power vs. frequency. Therefore, an analysis of reactive power 16 is necessary to increase the voltage profile of the system and thereby provide an improved power factor that decreases the stress on the load angle of the generator when voltage variation occurs.…”

“…Therefore, RPL control is also to be focused on for maintaining the VSG system stability and having a better power quality (PQ). Furthermore, a better perspective on the parameters design principle is obtained by small‐signal analysis, as mentioned in the literature 12–14 . Literature studies in 15 showed that a 1% increase/decrease in frequency causes a 6% to 12% decrease/increase in reactive power as it has a negative slope in the visual representation of reactive power vs. frequency.…”

Low-pass filtering or gain tuning free simple DC offset rejection technique for single and three-phase systems

“…Many applications in power electronics, machine and drives (PEMD) area require accurate information of the grid voltage signal. Some of the application examples are: grid-connected converter [1][2][3][4][5][6][7][8][9][10][11][12][13][14], active power flter [15], dynamic voltage restorer [16,17], electric vehicle on-board charger [18], motor drive as smart load [19], to name a few. These applications require fast and accurate estimation of single and three-phase grid voltage parameters.…”

Stability enhancement strategy of virtual synchronous generator for cascaded multilevel converter based energy storage system under weak grid conditions

“…Carmona-Sánchez et al [4] proposed a 'smart load' scheme based on the AC drives to realise power-frequency support, however, they are essentially one kind of energy-consuming load, thus it is difficult to provide enough energy to meet the megawattlevel fluctuation and power shortage. In comparison, as a typical 'flexible load' which can stabilise the voltage and frequency of power grid through charging or discharging the irregular and intermittent power, the energy storage system (ESS) becomes a promising and effective solution to the above problems [5][6][7].…”