Power taking device based on non-closed current transformer and control method thereof

Abstract

The invention discloses a power taking device based on a non-closed current transformer. The power taking device comprises the current transformer, a rectifying unit and a control unit. A diode rectifying filter unit of a traditional power taking device is replaced by an active rectifying filter unit completely formed by switching tubes. When a current of a transmission line is small, even if the power taking device is matched with a current transformer with a non-closed magnetic circuit and small magnetic inductance in use, enough output voltage and power also can be obtained and supplied to a load, so that the volume and manufacturing cost of the current transformer are reduced. When the current of the transmission line is large, the power taking device can avoid obtaining overlarge output voltage and power. The invention further discloses a control method of the power taking device. By means of the control method of the power taking device, when parameters of the transmission line, the power taking device, the load and the like change, direct current output voltage obtained by the power taking device is kept constant, so that power supplying stability of the power taking device is improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a power-taking device based on a non-closed current transformer and a control method thereof. Background technique [0002] In order to improve the safety and reliability of high-voltage transmission lines, online monitoring of their operating conditions is required, but it is very inconvenient to supply power to these monitoring equipment placed around the transmission lines, such as in the field or underground, generally cannot provide 220V AC mains power , and the stability and maintenance-free of photovoltaic panels or batteries are poor. Only the use of current transformers to directly obtain power from high-voltage transmission lines through electromagnetic induction is a relatively safe, stable, and long-term maintenance-free power supply method. However, the current of the high-voltage transmission line fluctuates greatly. The traditional current tr...

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Problems solved by technology

However, there are two problems with this method: first, the capacitance of the parallel capacitor must be strictly matched with the excitation inductance of the current transformer. When the inductance of the excitation inductance changes, this method cannot achieve the effect of significantly increasing the output impedance of the current transformer ; Second, the parallel capacitor must use a non-polar capacitor. When the excitation inductance is small, the capacitance and volume of the parallel capacitor are large

In this case, the output voltage and power obtained by the traditional power-taking device will be very low; and for the power-taking device with parallel capacitors, in order to significantly increase the output impedance of the current transformer, the capacitance and volume of the parallel capacitors are large , and the size of the air gap must be strictly controlled, so that it is not suitable for practical applications

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