A voltage transformation unit based on a power transmission system

Abstract

The application relates to the technical field of electric power metering, in particular to a voltage transformation unit based on an electric power transmission system, which comprises a rectifier circuit used for converting alternating current into direct current output; a filter circuit connected with the rectifier circuit and used for filtering the direct current to form a filter signal; and a voltage reduction circuit used for receiving the filter signal and reducing the filter signal to a predetermined signal output; wherein the voltage reduction circuit comprises a first integrated device; a fourth diode with a positive end grounded and a reverse end connected with a source of the first integrated device; and a second inductor with an input end connected with the source of the first integrated device and an output end connected with an output end of the voltage transformation unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power metering, and in particular to a voltage transformation unit based on a power transmission system. BACKGROUND

[0002] In the current Internet era, more and more electronic products tend to be more functional and intelligent, and sockets with on-off timing power consumption metering have become a standard configuration of intelligent devices. Usually, in the design of products implementing the above functions, the device for metering electric energy usually includes a voltage reduction unit. Existing voltage reduction units mostly use transformers for voltage reduction. However, transformers have relatively large volumes, so there are usually the following problems in the integration process: first, the volume of the transformer makes the volume or area of the circuit board or PCB relatively large, especially the layout of the circuit device is difficult to be compact, which brings inconvenience to the design of the product structure and appearance. In addition, the transformer has relatively large noise in the working state, which greatly affects the voltage sampling and current sampling, and the accuracy of the sampling data is low. The output voltage based on the sampling data is usually in an unstable state, which reduces the working precision of the metering device. SUMMARY

[0003] The present application aims to solve the problems in the prior art and provides a voltage transformation unit based on a power transmission system.

[0004] The present application provides a voltage transformation unit based on a power transmission system, which comprises:

[0005] a rectifier circuit for converting alternating current into direct current output;

[0006] a filter circuit connected to the rectifier circuit for filtering the direct current to form a filtered signal;

[0007] a voltage reduction circuit for receiving the filtered signal and reducing the filtered signal to a predetermined signal output; wherein

[0008] the voltage reduction circuit comprises:

[0009] a first integrated device;

[0010] a fourth diode, the positive terminal of which is grounded, and the negative terminal of which is connected to the source of the first integrated device;

[0011] a second inductor, the input terminal of which is connected to the source of the first integrated device, and the output terminal of which is connected to the output terminal of the voltage transformation unit.

[0012] Preferably, the voltage transformation unit based on the power transmission system further comprises a feedback unit, which comprises:

[0013] a first resistor, one end of the first resistor being connected to an output end of the voltage conversion unit,

[0014] a third resistor, one end of the third resistor being connected to the output end of the voltage conversion unit, the other end of the third resistor being connected to the other end of the first resistor to form a feedback connection end, the feedback connection end being connected to a feedback pin end of the first integrated device.

[0015] Preferably, the voltage conversion unit based on the power transmission system, wherein the resistance value of the first resistor is 5.6KΩ, and the resistance value of the third resistor is 4.99KΩ.

[0016] Preferably, the voltage conversion unit based on the power transmission system, wherein the filter circuit is formed by a first inductor, a fourth capacitor, and a fifth capacitor, the positive end of the fourth capacitor being connected to one end of the first inductor, the negative end of the fourth capacitor being connected to the negative end of the fifth capacitor, and the positive end of the fifth capacitor being connected to the other end of the first inductor.

[0017] Preferably, the voltage conversion unit based on the power transmission system, wherein the capacitance value of the fourth capacitor is 2.2uf, and the capacitance value of the fifth capacitor is 4.7uf.

[0018] Preferably, the voltage conversion unit based on the power transmission system, wherein the capacitance value of the fourth capacitor is 4.7uf, and the capacitance value of the fifth capacitor is 4.7uf.

[0019] Preferably, the voltage conversion unit based on the power transmission system, further comprising a fifth resistor, the fifth resistor being arranged between the negative end of the fourth capacitor and the negative end of the fifth capacitor.

[0020] Preferably, the voltage conversion unit based on the power transmission system, further comprising a sixth resistor, one end of the sixth resistor being connected to the negative end of the fourth capacitor, and the other end of the sixth resistor being connected to the second type of ground end.

[0021] Preferably, the voltage conversion unit based on the power transmission system, further comprising an electrostatic protection circuit, the electrostatic protection circuit being connected to the power input end.

[0022] Compared with the prior art, the voltage conversion unit based on the power transmission system has the following advantages:

[0023] In the present application, the linear non-isolated AD voltage reduction circuit is formed by the first integrated device, the size of the first integrated device is small, the pins of the first integrated device are relatively less, and the peripheral circuit is simple. In addition, the current overload capacity of the first integrated device is strong, the selection range of the input first integrated device internal resistance is large. There is more layout space on the PCB, the design of the volume is greatly improved compared with the isolated power supply, and convenience is provided for reducing the structural space. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A circuit diagram of a voltage transformation unit based on a power transmission system is provided in the present application.

[0025] Figure 2 A circuit diagram of a voltage transformation unit based on a power transmission system is provided in the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0027] As shown in Figure 1 The present application provides a voltage transformation unit based on a power transmission system, which comprises:

[0028] A rectifier circuit is used to convert alternating current into direct current output; further, the rectifier circuit is formed by a diode, the reverse end of the diode is connected to the power input end, the forward end of the diode is connected to the filter circuit, and the diode is single-sided rectification. Further, an overload protection device is further included at the front end of the diode.

[0029] A filter circuit is connected to the rectifier circuit, used to filter the direct current to form a filtered signal; further, the filter circuit is formed by a first inductor, a fourth capacitor and a fifth capacitor, the positive end of the fourth capacitor is connected to one end of the first inductor, the negative end of the fourth capacitor is connected to the negative end of the fifth capacitor, and the positive end of the fifth capacitor is connected to the other end of the first inductor.

[0030] Further, the above-mentioned voltage transformation unit based on a power transmission system, wherein the capacitance of the fourth capacitor is 4.7uf, and the capacitance of the fifth capacitor is 4.7uf. In the case that the capacitances of the fourth capacitor and the fifth capacitor are the same, a symmetric circuit based on the first inductor is formed, wherein the resistance of the first inductor is 1mH.

[0031] When the fourth capacitor adopts a 4.7uf capacitor, the volume of the capacitor is large, and based on this, further, the above-mentioned voltage conversion unit based on the power transmission system, wherein the capacitance of the fourth capacitor is 2.2uf, and the capacitance of the fifth capacitor is 4.7uf. A small volume capacitor of 2.2uf is adopted to facilitate circuit layout.

[0032] The voltage reduction circuit is used to receive the filtered signal and reduce the filtered signal to a predetermined signal output.

[0033] The voltage reduction circuit includes,

[0034] The first integrated device; the first integrated device can be formed by a chip. The current overload capacity of the first integrated device reaches 350ma.

[0035] The fourth diode, the positive end of the fourth diode is grounded, and the negative end of the fourth diode is connected to the source of the first integrated device.

[0036] The second inductor, the input end is connected to the source of the first integrated device, and the output end is connected to the output end of the voltage conversion unit.

[0037] The working principle of the present application is that 220V voltage is input to the rectifier circuit through the overload protection device, the rectifier circuit converts the 220V alternating voltage information into a 99V direct current signal output, the direct current signal is filtered by the filter circuit to form a voltage-stable direct current signal, and the direct current signal is transmitted to the voltage reduction circuit. The elements in the voltage reduction circuit and the fourth diode and the second inductor are combined with the PWM wave formed in the first integrated device to reduce the voltage of the direct current signal.

[0038] In the present application, a linear non-isolated AD voltage reduction circuit is formed by the first integrated device. The first integrated device is small in size, and the pins of the first integrated device are relatively few. In addition, the current overload capacity of the first integrated device is strong, and the selection range of the input resistance in the first integrated device is large. There is more layout space on the PCB, and the volume is greatly improved compared with the design of the isolated power supply, which provides convenience for reducing the structure space.

[0039] As a further preferred embodiment, the above-mentioned voltage conversion unit based on the power transmission system further comprises a feedback unit, which specifically comprises:

[0040] The first resistor, one end of the first resistor is connected to the output end of the voltage conversion unit,

[0041] A third resistor, one end of the third resistor is connected to the output end of the voltage transformation unit, the other end of the third resistor is connected to the other end of the first resistor to form a feedback connection end, the feedback connection end is connected to the feedback pin end of the first integrated device. A third capacitor is connected between the feedback connection end and the source, the capacitance of the third capacitor is 470pf. In the simulation circuit, the third capacitor is usually not needed, but in actual use, the resistance of the first integrated device itself cannot be ignored, in order to reduce the influence of the first integrated device itself on the circuit, the third capacitor is used to eliminate the influence.

[0042] The resistance of the first resistor is 5.6KΩ, and the resistance of the third resistor is 4.99KΩ.

[0043] Further comprising a first capacitor, the capacitance of the first capacitor is 220nf, one end of the first capacitor is connected to one end of the first resistor, the other end of the first capacitor is connected to one end of the third resistor, the first capacitor is connected in parallel with the first resistor and the third resistor to form an RC filter circuit, usually the value of the first capacitor matches the first resistor and the third resistor, and the first resistor and the third resistor are matched with the feedback connection end. The first capacitor is used to filter the resistance between the first resistor and the third resistor again, to further filter out the AC harmonics of the output voltage.

[0044] In use, the N end and the ground end of the 220V voltage are connected, which will generate more noise. As a further preferred embodiment, the above-mentioned voltage transformation unit based on the power transmission system further comprises a fifth resistor, the fifth resistor is arranged between the negative end of the fourth capacitor and the negative end of the fifth capacitor. The fifth resistor is a zero ohm resistor, and the fourth capacitor and the fifth capacitor can quickly release the stored electrical energy through the fifth resistor during discharge. In addition, the N end and the ground end are separated by the fifth resistor, which can effectively reduce the influence of noise on each functional circuit.

[0045] As shown in Figure 2 As a further preferred embodiment, the above-mentioned voltage transformation unit based on the power transmission system further comprises a sixth resistor, one end of the sixth resistor is connected to the negative end of the fourth capacitor, and the other end of the sixth resistor is connected to the second type of ground end. The N end is further isolated from the second type of ground end by the sixth resistor.

[0046] As a further preferred embodiment, the above-mentioned voltage transformation unit based on the power transmission system further comprises an electrostatic protection circuit, the electrostatic protection circuit is connected to the power input end.

[0047] The electrostatic protection circuit comprises an L-end electrostatic protection branch and an N-end electrostatic protection branch. The L-end electrostatic protection branch is formed by connecting a pair of diodes. One of the diodes is connected in parallel between the L output end and the ground in a forward direction, and the other diode is connected in parallel between the L output end and the ground in a reverse direction. Four 510KΩ resistors are arranged between the L output end and the diodes to divide the voltage of the L output end. When the electrostatic of KV is input from the input end, the diodes are reversely broken down, and the charges are rapidly discharged to the ground or the power supply. The positive electrostatic is mostly discharged to the power supply, and the negative electrostatic is mostly discharged to the ground. The purpose of reducing the signal noise and protecting the circuit is achieved.

[0048] Similarly, the N-end electrostatic protection branch comprises at least an N-end electrostatic protection input branch and an N-end electrostatic protection output branch. The N-end electrostatic protection input / output branch is formed by connecting a pair of diodes.

[0049] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A power transmission system based transformer unit, characterized by, The application relates to a rectifier circuit, a filter circuit, a step-down circuit and an electrostatic protection circuit. The rectifier circuit is used for converting alternating current into direct current output; The filter circuit is connected with the rectifier circuit and used for filtering the direct current to form a filtered signal; The filter circuit is formed by a first inductor, a fourth capacitor and a fifth capacitor, the positive terminal of the fourth capacitor is connected with one end of the first inductor, the negative terminal of the fourth capacitor is connected with the negative terminal of the fifth capacitor, and the positive terminal of the fifth capacitor is connected with the other end of the first inductor; The step-down circuit is used for receiving the filtered signal and step-down processing the filtered signal to a predetermined signal output; wherein, The step-down circuit comprises: A first integrated device which is used for step-down processing the filtered signal by an internally generated PWM wave; A fourth diode, the forward end of which is grounded, and the reverse end of which is connected with the source of the first integrated device; A second inductor, the input end of which is connected with the source of the first integrated device, and the output end of which is connected with the output end of the transformer unit; A feedback unit, which comprises a first resistor, one end of which is connected with the output end of the transformer unit, and a third resistor, one end of which is connected with the input end of the second inductor, and the other end of which is connected with the other end of the first resistor to form a feedback connection end, and the feedback connection end is connected with the feedback pin end of the first integrated device; A fifth resistor, which is arranged between the negative terminal of the fourth capacitor and the negative terminal of the fifth capacitor, and is a zero-ohm resistor; A sixth resistor, one end of which is connected with the negative terminal of the fourth capacitor, and the other end of which is connected with a second type of ground terminal.

2. A power transfer system based transformation unit as claimed in claim 1, characterized in that, The resistance value of the first resistor is 5.6K omega, and the resistance value of the third resistor is 4.99K omega.

3. A power transfer system based transformation unit as claimed in claim 1, characterized in that, The capacitance value of the fourth capacitor is 2.2uf, and the capacitance value of the fifth capacitor is 4.7uf.

4. A power transfer system based transformation unit as claimed in claim 1, characterized in that, The capacitance value of the fourth capacitor is 4.7uf, and the capacitance value of the fifth capacitor is 4.7uf.

5. A power transfer system based transformation unit as claimed in claim 1, characterized in that, The electrostatic protection circuit is connected with the power input end.

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