A voltage-controlled current source circuit using ct instead of current sensing resistor

Abstract

The invention discloses a voltage-controlled current source circuit using a CT to replace a current sensing resistor. Floating load and grounded load voltage-controlled current source circuit topologies are improved based on large current output, a sampling precision CT is introduced to replace the traditional current sensing resistor, the primary side of the CT is directly connected in series to the output loop of a power operational amplifier, and the secondary side is connected with a transfer resistor to feed back voltage signals. Thus, the limit put on the current output capacity of the circuit by the floating load and grounded load voltage-controlled current source circuits due to the current sensing resistor is eliminated, the situation in which power consumption is caused when the current flows through the current sensing resistor is avoided, and the efficiency of the voltage-controlled current source is greatly increased.

Description

technical field [0001] The invention belongs to the design field of high-power power electronic circuits, and more specifically relates to a novel voltage-controlled current source (VCCS) circuit, which mainly completes the conversion from voltage to current and realizes the function of the voltage-controlled current source circuit. Background technique [0002] Voltage-controlled current source (VCCS for short) is widely used in the fields of high-power semiconductor component testing, motor torque control and power measurement. VCCS is used for characteristic testing of high-power semiconductor components, and mainly plays the role of excitation source; VCCS is used for motor torque control because the torque and motor current present a functional relationship, so it is relatively simple, and the use of current drive in the servo loop can reduce the The phase lag caused by the inductance of the motor improves the stability of the loop; while VCCS is used for power measurem...

AI Technical Summary

Problems solved by technology

[0009] Since the above floating load and grounded load type voltage-controlled current source circuit topology adopts R S As a current sensing resistor and feedback control of current output, the output current flows directly through the current sensing resistor RS. When the output current is large, the loss and heat generated on RS will reduce the conversion efficiency of the VCCS circuit and directly affect Safe and reliable operation of VCCS

If you choose a current sensing resistor with a very low resistance value, you can theoretically reduce the loss on the resistor, but from the current resistor manufacturing process, it is difficult to guarantee the accuracy of a low resistance value (less than 0.1 ohm) resistor, so VCCS The accuracy of the voltage conversion current is difficult to be guaranteed

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