CN110138050A - A kind of distribution terminal super capacitor charging circuit of peak value comparison method mode - Google Patents

Abstract

The invention discloses a supercapacitor charging circuit of a power distribution terminal in a peak current control mode, comprising a switch tube. The output end of the switch tube is respectively connected with the cathode of the diode D and one end of the inductor L; the input and output ends of the switch tube are connected with the positive pole of the DC power supply; the control end of the switch tube is connected with the output end of the drive circuit. The other end of the inductor L is connected to the positive electrode of the supercapacitor C, and a current sensor T is provided on the connection line for detecting the current flowing through the line. The cathode of the supercapacitor C and the anode of the diode D are grounded. The output end of the current sensor T is connected to the first end of the comparator, the second end of the comparator is connected to the reference voltage point, the output end of the comparator is connected to the R end of the RS trigger; the S end of the RS trigger is connected to the pulse generator ; The output end of the RS flip-flop is connected with the input end of the drive circuit. The structure is simple, stable and reliable, and can effectively solve the problems of slow charging speed, low efficiency, large volume, and large heat generation.

Description

A power distribution terminal super capacitor charging circuit with peak current control mode

technical field

The invention relates to the technical field of super capacitor charging, in particular to a power distribution terminal super capacitor charging circuit in a peak current control mode.

Background technique

Feeder Terminal Unit (FTU for short) is the interface between the distribution automation system and the primary equipment. It can control the opening and closing of the primary switch equipment under specific conditions according to the set action logic to achieve fault location, fault isolation and Functions such as rapid power recovery in non-faulty areas.

According to the requirements of "DL/T 721-2013 Distribution Automation Remote Terminal", FTU generally uses lead-acid storage batteries or super capacitors as backup power sources. Due to the advantages of high charging power density, fast charging speed, large discharge current, long service life, and no environmental pollution, supercapacitors are widely used in remote terminals of power distribution automation. However, at this stage, the power resistor current limiting method is generally used to charge the super capacitor. This charging method has slow charging speed and low efficiency, and the power resistor is bulky and generates heat during charging. In the FTU, the application of this charging method is greatly limited.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention adopts the following technical solutions to realize:

A power distribution terminal supercapacitor charging circuit in a peak current control mode, comprising a switch tube, a diode D, an inductance L, a current sensor T, a supercapacitor C, a comparator, an RS trigger, a pulse generator and a drive circuit;

The output end of the switch tube is connected with the cathode of the diode D and one end of the inductor L respectively; the input and output ends of the switch tube are connected with the positive pole of the DC power supply; the control end of the switch tube is connected with the output end of the drive circuit;

The anode of diode D is grounded;

The other end of the inductor L is connected to the positive electrode of the supercapacitor C;

A current sensor T is provided on the line between the other end of the inductor L and the positive electrode of the supercapacitor C, for detecting the current flowing through the line;

The negative electrode of supercapacitor C is grounded;

The output end of the current sensor T is connected to the first end of the comparator, the second end of the comparator is connected to the reference voltage point, the output end of the comparator is connected to the R end of the RS trigger; the S end of the RS trigger is connected to the pulse generator ; The output end of the RS flip-flop is connected with the input end of the drive circuit.

Preferably, the switch tube is a field effect transistor.

Preferably, the driving circuit includes a UC3840 control chip.

The output terminal of the current sensor T is connected to the inverting input terminal of the hysteresis comparator, the non-inverting input terminal of the hysteresis comparator is connected to the reference voltage V _ref , the output terminal of the comparator is connected to the R input terminal of the RS flip-flop, and the output terminal of the periodic pulse generator is connected to The S input terminal of the RS flip-flop, the Q output terminal of the RS flip-flop is connected to the input terminal of the driving circuit, and the output terminal of the driving circuit is connected to the gate of the _Mosfet . To achieve the purpose of charging the super capacitor C smoothly. The circuit has a simple structure, is easy to implement, is stable and reliable, and can effectively solve the problems of slow charging speed, low efficiency, large size of the power resistor, and large heat during charging.

Description of drawings

Fig. 1 is the circuit structure diagram provided by the present invention;

Fig. 2 is a control waveform diagram provided by the present invention;

FIG. 3 is a simulation diagram provided by the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings 1 to 3 in the embodiments of the present application. The embodiments described above are part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. Thus, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

As shown in Figure 1, a power distribution terminal supercapacitor charging circuit in a peak current control mode includes a switch tube, a diode D, an inductor L, a current sensor T, a supercapacitor C, a comparator, an RS trigger, a pulse generator and Drive circuit.

The switch tube is a field effect tube (Mosfet), and the output end (source) of the switch tube is connected to the cathode of the diode D and one end of the inductor L respectively; the input and output ends (drain) of the switch tube are connected to the positive pole of the DC power supply; the switch tube The control terminal (gate) is connected to the output terminal of the drive circuit.

The anode of diode D is grounded.

The other end of the inductor L is connected to the positive pole of the supercapacitor C, and the negative pole of the supercapacitor C is grounded. The supercapacitor C is connected to the FTU to provide it with electrical energy.

A current sensor T is provided on the line between the other end of the inductor L and the positive electrode of the supercapacitor C for detecting the current flowing through the line. The current sensor T can be connected in series in the line under test, that is, the pin is welded on the line. It can also be a ring structure sleeved on the line. There is no specific limitation here. In short, the purpose is to obtain the current signal on the line through the transformer, and obtain the voltage through the parallel resistance.

The output end of the current sensor T is connected to the first end (positive input end) of the comparator, and the second end (negative input end) of the comparator is connected to the reference voltage point. The reference voltage point is provided by the reference voltage circuit, which can be replaced by a mature module.

The output end of the comparator is connected with the R end of the RS flip-flop. The S terminal of the RS flip-flop is connected to the pulse generator. The output end of the RS flip-flop is connected with the input end of the driving circuit. The drive circuit adopts UC3840 control chip, which is used to realize the control of the switch tube.

The combination of switch tube, diode D, and inductor L constitutes a buck non-isolated topology DC buck circuit. The input terminal of the buck DC buck circuit is connected to the positive pole of the DC power supply, the output terminal of the buck DC buck circuit is connected to the positive pole of the super capacitor, and the current sensor T reduces the buck DC to the positive pole. The inductor current i _o of the voltage circuit is proportionally converted into a voltage _VT output. The output terminal of the current sensor T is connected to the inverting input terminal of the hysteresis comparator, the non-inverting input terminal of the hysteresis comparator is connected to the reference voltage V _ref , the output terminal of the comparator is connected to the R input terminal of the RS flip-flop, and the output terminal of the periodic pulse generator is connected to The S input terminal of the RS flip-flop, the Q output terminal of the RS flip-flop is connected to the input terminal of the driving circuit, and the output terminal of the driving circuit is connected to the gate of the Mosfet.

The current sensor T outputs V _T =n× i _o , where n is a positive constant, and the magnitude is changed by adjusting the resistance parameters of the current sensor. The output of the current sensor T is connected to the inverting input of the comparator. When the pulse generator outputs a pulse signal, the RS flip-flop outputs a high level, and after passing through the driving circuit, the switching tube Mosfet is driven to conduct, and the inductor current rises. When the current sensor T outputs V _T > V _ref , the comparator outputs a high level, and the RS flip-flop outputs a low level. After passing through the driving circuit, the driving switch Mosfet is turned off, and the inductor current decreases. FIG. 2 is a waveform diagram provided by the present invention, and FIG. 3 is an example simulation result.

The present invention utilizes that the output end of the current sensor T is connected to the inverting input end of the comparator, the non-inverting input end of the comparator is connected to the reference voltage V _ref , the output end of the comparator is connected to the R input end of the RS trigger, and the output end of the periodic pulse generator is connected to the RS The S input end of the flip-flop, the Q output end of the RS flip-flop is connected to the input end of the drive circuit, the output end of the drive circuit is connected to the gate of the Mosfet, and the peak value of the output current i ₀ of the buck DC step-down circuit is controlled to achieve The purpose of charging the super capacitor C smoothly. The circuit has a simple structure, is easy to implement, is stable and reliable, and can effectively solve the problems of slow charging speed, low efficiency, large size of the power resistor, and large heat during charging.

Claims (3)

1. the power distribution terminal supercapacitor charging circuit of a peak current control mode, is characterized in that, comprises switch tube, diode D, inductance L, current sensor T, supercapacitor C, comparator, RS trigger, pulse generator and Drive circuit; The output end of the switch tube is connected with the cathode of the diode D and one end of the inductor L respectively; the input and output ends of the switch tube are connected with the positive pole of the DC power supply; the control end of the switch tube is connected with the output end of the drive circuit; The anode of diode D is grounded; The other end of the inductor L is connected to the positive electrode of the supercapacitor C; A current sensor T is provided on the line between the other end of the inductor L and the positive electrode of the supercapacitor C, for detecting the current flowing through the line; The negative electrode of supercapacitor C is grounded; The output end of the current sensor T is connected to the first end of the comparator, the second end of the comparator is connected to the reference voltage point, the output end of the comparator is connected to the R end of the RS trigger; the S end of the RS trigger is connected to the pulse generator ; The output end of the RS flip-flop is connected with the input end of the drive circuit. 2. the power distribution terminal supercapacitor charging circuit of peak current control mode according to claim 1, is characterized in that: The switch tube is a field effect tube. 3. the power distribution terminal supercapacitor charging circuit of peak current control mode according to claim 1, is characterized in that: The drive circuit includes a UC3840 control chip.