Design of current sharing system for mine explosion-proof lithium power supply

In order to solve the problem of uneven discharge current when multiple mine explosion-proof lithium power supplies are used in parallel, a current sharing system for mine explosion-proof lithium power supply is designed. The system is composed of several explosion-proof lithium power supplies connected in parallel. The explosion-proof lithium power supplies adopt 166 60 A·h lithium iron phosphate batteries connected in series in the explosion-proof cavity. The digital current sharing strategy based on the average current is adopted, the current sharing controller is used as the current adjustment component, and the double closed-loop control is adopted. The inner loop of the system is a current loop, and the outer loop is a voltage loop. A current sharing compensation is added to the voltage loop. The current sharing control is realized through voltage deviation signal and current sharing compensation signal. The test results show that after the current sharing system is adopted, the current sharing unbalance degree is 1%~2% when the total load current is 20 A, and the current sharing unbalance degree is kept within 1% when the total load current is greater than 30 A. Compared with the power supply without current sharing strategy, the parallel current sharing effect of power supplies using digital current sharing strategy is better and the power supply reliability is higher.