A Transient Electromagnetic Method Pulse Current Transmitting Circuit

Abstract

The invention relates to a pulse current transmission circuit adopting a transient electromagnetic method, and especially an emission current control circuit applicable to a multi-turn loop transmitting device of a magnetic source. A main power supply is connected with a Buck ZCS (Zero-Current-Switching)-PWM (Pulse-Width Modulation) converter, and the Buck ZCS-PWM converter controls the voltage at the two ends of a transmitting coil, so that the current of a rising edge and a flat top segment can be controlled; the Buck ZCS-PWM converter is connected with an H-bridge circuit, so as to control the current flow and realize that an emission current waveform is a bipolar trapezoidal wave; the H-bridge circuit is connected with the transmitting coil, and block diodes are connected to joints of the upper and lower bridge arms of the H-bridge circuit and the transmitting coil; the block diode is used for blocking the current of the transmitting coil from flowing towards the upper and lower bridge arms of the H-bridge circuit, and the blocking eliminates resonance caused by the current between a parasitic capacitor of the circuit and the transmitting circuit; the two ends of the transmitting coil are connected to an energy feedback constant voltage clamping circuit in parallel, wherein the energy feedback constant voltage clamping circuit controls a current falling edge, so that a clamp voltage of the current falling edge is improved and the falling edge time is shortened.

Description

technical field [0001] The invention relates to a transient electromagnetic pulse current transmitting circuit, in particular to a transmitting current control circuit suitable for a multi-turn coil transmitting device of a magnetic source. Background technique [0002] Magnetic source electromagnetic method instruments usually use H-bridge circuit as the main power conversion circuit of the transmitting device, and the load is inductive. In order to reduce the power loss of the load resistance, a coil load with large inductance and small resistance is usually used, especially in the aviation electromagnetic method and downhole electromagnetic method. The size of the coil is limited in special occasions such as the law, and in fact most of them use small coils with multiple turns. Therefore, special requirements are put forward for the power conversion circuit of the magnetic source electromagnetic method transmitter. [0003] Since the resistance of the load coil is relati...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a transient electromagnetic method pulse current transmitting circuit, which solves the problem that the switching tube of the upper bridge arm of the H-bridge circuit performs PWM hard-opening technology to control the voltage switching loss at both ends; after the H-bridge circuit is turned off The reverse overshoot of the falling edge current is large, and the oscillation tail time is long, which affects the data acquisition of the receiver

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