Purpose This paper aims to propose an integrated protection scheme for converters of a low-power, low-cost photovoltaic system. Power electronic converters use a variety of methods to limit overload and fault current. The use of insulated and non-insulated sensors along with additional circuits to detect and limit fault current can cause current to be limited or completely cut off before damage to semiconductor devices. In addition, fuses that have slower performance are used as backup for any type of protection. Design/methodology/approach First, all the candidate points for protection are investigated. In this paper, after examining the performance of glass fuses as linear resistors, they are used as a current feedback element. A simple, isolated and reliable circuit for fault detection at various points of the system has been proposed that can be implemented and operated in single shot or auto-reclose operating mode. Findings The experimental results of this circuit on a dc/dc converter and an H-bridge inverter show that it can cut off all instantaneous short circuit errors in less than 50 µs and prevent damage to the semiconductor switch. Originality/value In low-cost and low-power converters, it is usually not cost-effective to use complex and expensive devices. For this reason, these converters are more vulnerable to faults. On the other hand, in complex systems such as photovoltaics, several converters are used simultaneously in different parts, and the occurrence of a fault in each of them causes the whole system to fail.
Summary This paper investigates the performance of a battery‐less photovoltaic desalination system. Lead‐acid batteries have been removed from the system due to adverse environmental effects, a shorter lifespan, and to reduce the total cost. Due to the lack of a storage device, starting a high current load like an AC compressor leads to electrical instability of the system. The proposed solution for this problem includes using a combination of two high‐capacity electrolyte capacitors, one at the PV terminals and the other at the single‐phase inverter input terminals. Suitable resistive starters have also been sized and added to the circuit to limit the inrush current of capacitors at the energization moment. An analytical procedure has been introduced to design the optimal size of the capacitors and the starter resistors. The results of a 1.1 kW test system show that using two capacitors, 12 000 μf/ 350 Volts as C1 and 330 000 μf/ 50 Volts as C2, at the same time, can handle a starting current of 12 Amps for the starting period of 100 ms of the AC compressor. The maximum voltage drop on the capacitors will be 48 and 17%, which are in the accepted range, and no instability happens.
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