A split-type capacitor power supply device

Abstract

This invention discloses a split-type capacitor-driven power supply device, aiming to solve the problems of large size and ferroresonance risk of traditional electromagnetic PTs. The device includes physically separated high-voltage and low-voltage modules connected by cables. The high-voltage module is connected to a high-voltage conductor and couples electrical energy through a capacitor-driven energy extraction unit for preliminary conversion; the low-voltage module receives this energy and converts it into stable DC power output. This invention achieves complete electrical isolation between the high and low voltage sides through physical separation, eliminating the risk of ferroresonance and offering advantages such as high safety, small size, and high reliability.

Description

Technical Field

[0001] This utility model belongs to the field of power systems, and in particular relates to a split capacitor power supply device. Background Technology

[0002] In current power systems, traditional electromagnetic voltage transformers (PTs) are commonly used for voltage measurement, protection, and control on medium- and high-voltage transmission and distribution lines such as 10kV. These PTs operate based on the principle of electromagnetic induction, converting high voltage into a standard low-voltage signal. However, existing electromagnetic PTs have several inherent drawbacks:

[0003] Traditional electromagnetic PTs, especially high-precision models, contain iron cores and multi-stage windings, resulting in a complex structure that makes them bulky and heavy. This not only makes transportation and installation inconvenient but also limits their application in compact substations or gas-insulated switchgear (GIS) systems where space is limited.

[0004] In power grid systems where the neutral point is not effectively grounded, the nonlinear core inductance of electromagnetic power PTs and the line-to-ground current can easily form a resonant circuit, triggering ferroresonant overvoltages. These overvoltages severely threaten the safety of the PT itself and connected equipment, potentially causing the PT to burn out or its high-voltage side fuse to blow. To suppress resonance, additional harmonic suppression devices are usually required, increasing system complexity and cost. When a near-circuit fault occurs in the power system, the line voltage drops sharply, and the huge transient current may cause the PT core to enter a saturated state. Core saturation severely distorts the voltage waveform output from the secondary side, making it unable to accurately reflect changes in the primary side voltage. This can lead to maloperation or failure to operate of voltage-signal-dependent protection devices (such as distance protection and undervoltage protection), endangering grid stability.

[0005] Therefore, how to overcome the above-mentioned defects of traditional electromagnetic PTs and provide a safer, more reliable, smaller and maintenance-free high-voltage power supply solution is a technical problem that urgently needs to be solved in this field. Utility Model Content

[0006] The purpose of this invention is to provide a split-type capacitor power supply device to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the specific technical solution of the split-type capacitor power supply device of this utility model is as follows:

[0008] A split-type capacitor-driven power supply device includes a high-voltage module suitable for electrical connection to a high-voltage conductor, wherein the high-voltage module includes:

[0009] A capacitor-driven energy harvesting unit is used to couple electrical energy from the high-voltage conductor; and

[0010] The first-stage power conversion circuit is connected to the capacitor energy harvesting unit and is used to initially convert the coupled electrical energy into intermediate electrical energy.

[0011] The low-voltage module is physically separated from the high-voltage module; and

[0012] A connecting cable is used to transmit the intermediate electrical energy output by the high-voltage module to the low-voltage module;

[0013] The low-voltage module includes a second-stage power conversion circuit for receiving the intermediate electrical energy and converting it into stable DC power output.

[0014] Furthermore, the high-voltage module also includes:

[0015] A signal processing and isolation unit is used to sense the voltage state of the high-voltage conductor and generate an isolated state signal; and

[0016] An onboard power supply circuit utilizes a portion of the electrical energy coupled by the capacitor power harvesting unit to power the signal processing and isolation unit.

[0017] Furthermore, the capacitor energy harvesting unit includes at least one energy harvesting capacitor connected in series with the high-voltage conductor.

[0018] Furthermore, the first-stage power conversion circuit includes a rectifier circuit and a filter clamping circuit, used to convert the AC power output by the capacitor power harvesting unit into pulsating DC or DC power with a preset voltage amplitude as the intermediate power.

[0019] Furthermore, the second-stage power conversion circuit is a switching power supply circuit, which includes a feedback control loop for stabilizing the DC power output.

[0020] Furthermore, the feedback control loop includes:

[0021] A voltage sampling unit for sampling the DC power output; and

[0022] An isolated feedback unit adjusts the switching duty cycle of the switching power supply circuit based on the sampling results of the voltage sampling unit to achieve a constant output voltage.

[0023] Furthermore, the signal processing and isolation unit includes:

[0024] A voltage divider network connected to the high-voltage conductor; and

[0025] An optocoupler is provided, wherein the input terminal of the optocoupler is connected to the voltage divider network, and the output terminal is used to output the isolated status signal, thereby achieving electrical isolation between the high-voltage side and the low-voltage side.

[0026] Furthermore, the high-voltage module also includes a transient voltage suppression circuit for suppressing surge overvoltage on the high-voltage conductor.

[0027] Furthermore, the connecting cable is a shielded cable with a shielding layer to enhance the anti-interference capability of the intermediate power transmission.

[0028] Furthermore, the high-voltage module is adapted to be installed on the high-voltage conductor using an insulating clamp, and the low-voltage module is adapted to be installed in a control box that maintains a preset safe distance from the high-voltage conductor. The preset safe distance ensures the insulation safety between the high-voltage side and the low-voltage side.

[0029] This utility model's split-type capacitor-driven power supply device has the following advantages: Through the physical separation of high-voltage and low-voltage modules and the connection of shielded cables, complete physical isolation is achieved. This design fundamentally avoids the risk of high voltage being directly conducted to the low-voltage control side, reducing the probability of equipment breakdown. Simultaneously, because the capacitor voltage division principle is used instead of the iron core, the conditions for ferroresonance are eliminated, eliminating the need for additional harmonic suppression devices. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0031] Figure 2 This is a schematic diagram of the capacitor energy harvesting unit of this utility model;

[0032] Figure 3 Circuit diagram of the high-voltage module of this utility model;

[0033] Figure 4 Circuit diagram of the low-voltage module of this utility model.

[0034] The markings in the diagram are as follows: 1. High-voltage module; 2. Low-voltage module; 3. Connecting cable. Detailed Implementation

[0035] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed account of a split-type capacitor power supply device.

[0036] A split-type capacitor-powered power supply device, the core idea of ​​which is to physically divide the power supply device into a high-voltage module 1 and a low-voltage module 2, which are connected by a cable to achieve complete physical isolation and safety between the high-voltage side and the low-voltage side.

[0037] In a specific embodiment, such as Figure 1 As shown, this device includes a high-voltage module 1, a low-voltage module 2, and a connecting cable 3 connecting the two.

[0038] High-voltage module 1 is designed to be directly electrically connected to a high-voltage conductor (e.g., a 10kV busbar). Internally, high-voltage module 1 integrates a capacitor power extraction unit and a first-stage power conversion circuit.

[0039] The function of the capacitor-based energy harvesting unit is to couple electrical energy from the high-voltage conductor. Specifically, for example... Figure 2 As shown, the unit may include at least one energy-harvesting capacitor, which is connected in series with the high-voltage conductor. In this embodiment, the CL voltage divider principle is used to obtain energy from the 10kV line through a 3000-type capacitor unit. The high voltage is shared by connecting components in series, ensuring the safety of individual components.

[0040] The first-stage power conversion circuit is connected to the output of the capacitor-harvested unit and is responsible for the initial conversion of the coupled high-frequency AC power into intermediate power, preparing it for subsequent transmission and fine processing. Specifically, this first-stage power conversion circuit includes a rectifier circuit and a filter clamping circuit. The rectifier circuit can use a bridge rectifier (D8) of model KBP210G to convert the AC power output from the harvested unit into pulsating DC power. Subsequently, this pulsating DC power is smoothed by a filter circuit composed of capacitors C11, C12, and C13. In order to obtain a relatively stable voltage, a clamping circuit composed of two 24V Zener diodes (or TVS) DW3 and DW4 connected in series is also set in the circuit. They clamp the output voltage to a preset stable value, which serves as the intermediate power and is transmitted to the low-voltage module 2 through the connecting cable 3.

[0041] Low-voltage module 2 is physically separate from high-voltage module 1 and is installed in a safe area. It receives intermediate power from high-voltage module 1 via connecting cable 3.

[0042] The core of low-voltage module 2 is the second-stage power conversion circuit, which receives intermediate electrical energy and accurately converts it into stable DC power output, such as providing 28V / 0.5A DC power to secondary control circuits or online monitoring equipment.

[0043] Connecting cable 3 is used to connect high-voltage module 1 and low-voltage module 2, transmitting the aforementioned intermediate electrical energy. To enhance the anti-interference capability of signal transmission, a shielded cable with a shielding layer is preferred. Furthermore, the cable insulation layer can be specially thickened to prevent damage caused by external factors such as lightning strikes.

[0044] To achieve more advanced functions and higher safety, the high-voltage module 1 in this embodiment further includes a signal processing and isolation unit, an onboard power supply circuit, and a transient voltage suppression circuit.

[0045] The signal processing and isolation unit is used to sense the voltage state of the high-voltage conductor (e.g., the presence or absence of voltage) and generate a status signal that is completely electrically isolated from the high-voltage side for use by the control or monitoring system on the low-voltage side. Specifically, this unit includes a voltage divider network and an optocoupler.

[0046] The voltage divider network is directly connected to the high-voltage input terminal (e.g., via 5kV withstand pads J9, J10, J11). This network consists of multiple resistors connected in series, such as R7 (3.3kΩ), R8 (1.1kΩ), R9 (100kΩ), R12 (22kΩ), and R13 (2.7kΩ). This voltage divider network proportionally attenuates high voltages of up to 10kV to a very low, safe voltage.

[0047] The divided signal is used to control the conduction of MOSFETs Q3 and Q4. A bidirectional trigger diode D10 (DB3TG / ST) is specially set in the circuit as a threshold switch. Transistor Q4 can only conduct when the voltage of the high-voltage wire is high enough that the voltage applied across D10 after voltage division exceeds its trigger voltage.

[0048] Optocouplers, such as U2 of model LDA-140S, are key to achieving isolation. When Q4 is turned on, a current loop is formed that flows through the internal light-emitting diode (LED) of optocoupler U2. The LED emits light, illuminating the internal photosensitive receiver, causing it to conduct. This transmits the "energized" state signal from the high-voltage side to the low-voltage side in the form of light without contact, achieving complete electrical isolation.

[0049] like Figure 3 As shown, the onboard power supply circuit utilizes a portion of the electrical energy coupled by the capacitor energy extraction unit to provide operating power for the active devices on high-voltage module 1 (such as the optocoupler U2 in the aforementioned signal processing and isolation unit). The implementation of this circuit is similar to the first-stage power conversion circuit described above, generating a stable low-voltage onboard power supply through bridge rectification (D8), capacitor filtering (C11, C12, C13), and Zener diode clamping (DW3, DW4).

[0050] To protect the precision electronic components inside high-voltage module 1, a transient voltage suppression circuit is also integrated. This circuit uses transient voltage suppression diodes (TVS). For example, TVS diodes D5 and D6 (9V0CG / 5.0) are used to absorb potential surge overvoltages at the high-voltage input terminal. At the same time, TVS diode DW5 and an SMBJ5355B-TP / 18V TVS diode are used to protect the gate and source of MOSFETs Q3 and Q4 respectively, preventing them from being broken down by excessively high transient voltages.

[0051] like Figure 4As shown, in the low-voltage module 2, the second-stage power conversion circuit is preferably a high-efficiency and stable switching power supply circuit (SMPS).

[0052] This switching power supply circuit can be a typical isolated flyback topology. Its input first suppresses inrush current through a fuse resistor R1 and a negative temperature coefficient thermistor R2 (NTC), and then forms a high-voltage DC bus through a bridge rectifier D1 (GBU8M) and filter capacitors C19, C18, C21, etc.

[0053] The main switch Q1 (STN1DIT) operates under high-frequency drive, transferring energy to the secondary side through a transformer. On the secondary side, through the freewheeling diode D4 (SK36) and output filter capacitors C15 and C23, a stable DC power output (e.g., VCC_29V) is ultimately generated.

[0054] To ensure a constant output voltage, the switching power supply circuit includes a feedback control loop. This loop further includes a voltage sampling unit and an isolated feedback unit.

[0055] The voltage sampling unit consists of a precision adjustable reference source U2 (TL431BQDBZT) and voltage divider resistors R24 and R23. It accurately samples the DC voltage (VCC_29V) at the output terminal.

[0056] The core of the isolation feedback unit is an optocoupler (not shown separately in the diagram, but it's a standard design). When the output voltage fluctuates, the sampling result from the voltage sampling unit changes the current flowing through the LED in the optocoupler. The change in the intensity of the light signal is fed back to the primary side of the power supply, thereby adjusting the duty cycle of the main switch Q1, ultimately achieving closed-loop stable control of the output voltage. Its stable voltage satisfies the formula Vout = 2.5V * (1 + R24 / R23).

[0057] In addition, the low-voltage module 2 can also integrate power control functions as needed. For example, through a bidirectional thyristor (TRIAC) X1 (BTA20-800CW) and its trigger circuit, the external AC load can be switched or its power regulated.

[0058] In practical deployment, the high-voltage module 1 can be easily installed on the high-voltage conductor or busbar using insulating clamps. The low-voltage module 2 is installed in a control box on the ground or pole, maintaining a preset safe distance (e.g., ≥1.5 meters) from the high-voltage conductor. This installation method ensures the safety of operators and also makes maintenance and repair extremely convenient, as most of the complex control circuits and power conversion circuits are located in the easily accessible low-voltage module 2.

[0059] In summary, this utility model eliminates the ferroresonance problem of traditional electromagnetic PTs from a structural perspective through the separate design of high and low voltage modules 2. By using capacitor power extraction and multi-stage power conversion as the core, combined with various technical means such as opto-isolation and transient suppression, it provides a miniaturized, highly safe, highly reliable and maintenance-free online power extraction solution.

[0060] As can be understood by those skilled in the art, this utility model is described through various embodiments. Without departing from the spirit and scope of this utility model, various changes or equivalent substitutions can be made to these features and embodiments. Furthermore, under the teachings of this utility model, modifications can be made to these features and embodiments to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this utility model.

[0061] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A split capacitor power supply device, characterized by comprising: include: High-voltage module, adapted for electrical connection to high-voltage conductors, the high-voltage module comprising: A capacitor-driven energy harvesting unit is used to couple electrical energy from the high-voltage conductor; and The first-stage power conversion circuit is connected to the capacitor energy harvesting unit and is used to initially convert the coupled electrical energy into intermediate electrical energy. The low-voltage module is physically separated from the high-voltage module; and A connecting cable is used to transmit the intermediate electrical energy output by the high-voltage module to the low-voltage module; The low-voltage module includes a second-stage power conversion circuit for receiving the intermediate electrical energy and converting it into stable DC power output.

2. The split capacitive power sourcing unit of claim 1, wherein, The high-voltage module also includes: A signal processing and isolation unit is used to sense the voltage state of the high-voltage conductor and generate an isolated state signal; and An onboard power supply circuit utilizes a portion of the electrical energy coupled by the capacitor power harvesting unit to power the signal processing and isolation unit.

3. The split capacitive power sourcing unit of claim 1, wherein, The capacitor energy harvesting unit includes at least one energy harvesting capacitor connected in series with the high-voltage conductor.

4. The split capacitive power sourcing unit of claim 2, wherein, The first-stage power conversion circuit includes a rectifier circuit and a filter clamping circuit, used to convert the AC power output by the capacitor power extraction unit into pulsating DC or DC power with a preset voltage amplitude as the intermediate power.

5. The split capacitive power sourcing unit of claim 1, wherein, The second-stage power conversion circuit is a switching power supply circuit, which includes a feedback control loop for stabilizing the DC power output.

6. The split capacitive power sourcing unit of claim 5, wherein, The feedback control loop includes: A voltage sampling unit for sampling the DC power output; and An isolated feedback unit adjusts the switching duty cycle of the switching power supply circuit based on the sampling results of the voltage sampling unit to achieve a constant output voltage.

7. The split capacitive power sourcing unit of claim 2, wherein, The signal processing and isolation unit includes: A voltage divider network connected to the high-voltage conductor; and An optocoupler is provided, wherein the input terminal of the optocoupler is connected to the voltage divider network, and the output terminal is used to output the isolated status signal, thereby achieving electrical isolation between the high-voltage side and the low-voltage side.

8. The split capacitive power harvesting power supply device according to any one of claims 1 to 7, wherein The high-voltage module also includes a transient voltage suppression circuit for suppressing surge overvoltage on the high-voltage conductor.

9. The split capacitive power sourcing unit of claim 1, wherein, The connecting cable is a shielded cable with a shielding layer.

10. The split capacitive power sourcing unit of claim 1, wherein, The high-voltage module is adapted to be installed on the high-voltage conductor using an insulating clamp, and the low-voltage module is adapted to be installed in a control box that maintains a preset safe distance from the high-voltage conductor.

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