IPM在电法发送机上应用时的死区时间选择

Dead time selection of transmitter for electrical exploration based on IPM

IPM是IGBT智能模块的简称,它集功率变换,驱动及保护电路于一身,简化了逆变器外围电路设计,大大缩短了发送机开发周期.而IPM的运用要注意一个很重要的问题:死区时间的设置.在电法勘探发送机中,负载感抗有时比较大,而感抗的大小则会影响到IPM的关断时间.因此要求发送机的死区时间设定范围比较大,同时还要求在不同的发送频率下死区时间可调.如大极距和小极距由于供电回路大小不同而导致的感抗不同就要采用不同的设定值,同时高频时则要求死区时间在满足要求的情况下尽可能的小,否则会引起输出严重失真.综合以上考虑以及硬件实现上的方便性,可将死区时间设定为可调的几档,分别对应不同的勘探方法和不同的使用条件.

IPM is acronym of intelligent power module, which is integrated with power transform circuit.driver circuit and protecting circuit. Using it can simplify peripheral circuit of the inverter, and save time for designing a transmitter greatly. But the setting of dead time is a very important issue when we use IPM. In electrical exploration, inductance of load, which influence toff of IPM, is large sometimes. So, the dead time of a transmitter is needed to be long correspondingly. Meanwhile, it＇s necessary that the dead time can be changed in different transmitting frequencies. For instance, when we use long polar distances, the area inside transmitting wire is bigger than the short ones, and the inductance is larger, too. On the other hand, when we choose higher frequencies, shorter dead time is needed, otherwise there will be a serious distortion. Considering of above conditions and the convenience of hardware designing, the dead time should be set in some adjustable options. Different selection can be chosen according to different geophysical exploration methods and practical conditions.