Abstract: By using the method of integral calculation for sampled current and voltage， an accurate experiment system was designed to control the minimum spark discharge energy of dust clouds. Through insulated gate bipolar transistors， the discharge of the residual energy in the circuit was controlled， thus the discharge time was different and controllable under the same discharge energy. And the purpose of controlling the minimum ignition energy and the discharge rates at the same time was realized based on the proposed system. The results showed that the control error of 5% could be obtained for 100J and 10J energy. When the energy was 1J， the control error was about 10%. For the aluminum powder with the diameter range of 8 ~ 13μm， when the discharge energy was 1J， the shorter the discharge time was， the easier the dust cloud was lit. It is indicated that the aluminum powder is easier to be ignited at high rate of energy input.

Key words: minimum ignition energy, accurate control of energy, spark energy, energy input rate, dust clouds