Power taking device based on maximum power point tracking

Abstract

The utility model discloses an electricity taking device based on maximum power point tracking, which comprises a rectifier and a capacitor which are connected in series with a current transformer, and further comprises a maximum power tracker used for obtaining voltage and current of the capacitor and carrying out power tracking, the current transformer is provided with a protector used for switching the short circuit / open circuit state of the current transformer, and the maximum power tracker is further connected with the load and the protector and used for supplying power to the load and providing control signals for the protector. According to the utility model, the maximum power point output by the current transformer can be tracked under different currents, and the current transformer can stably work at the maximum power point so as to improve the efficiency. The current transformer is installed on an electric power circuit, one current transformer or two current transformers can be flexibly selected to be used according to actual load requirements, or a plurality of power supply groups are connected in parallel so as to meet high-load power utilization requirements, and in a high-load state, the installation number of the front-end current transformers can be effectively reduced, or the size and the weight can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric power, and in particular relates to a power taking device based on maximum power point tracking. Background Art

[0002] With the development of the national economy and the continuous expansion of power grids, the reliability of high-voltage distribution lines faces a significant challenge. Real-time monitoring of high-voltage line status has become a key measure to ensure reliable operation, which requires the installation of power monitoring equipment on high-voltage lines. However, power monitoring equipment cannot directly use the energy on the line, which greatly limits the deployment and operation of various monitoring devices.

[0003] Currently, there are three primary power supply methods for monitoring equipment on high-voltage lines: supercapacitor solutions (using supercapacitor energy storage), high DC voltage solutions (maximizing the DC voltage after the input rectifier bridge), and large CT solutions (unlimited current transformer size). However, supercapacitor solutions have low power supply efficiency. During startup, the secondary voltage is clamped very low, far below the CT's maximum power point. Furthermore, due to the low voltage rating of supercapacitors, the system input voltage is also very low. High DC solutions cannot utilize large energy storage capacitors, resulting in high power ripple and inability to absorb sudden surges on the primary side. Furthermore, high DC voltages can easily cause board-level breakdown, making high-voltage DC / DC components difficult to select and install, resulting in poor circuit protection and stability. The output power of large CTs is proportional to their weight, and unrestricted CT size ultimately makes them impossible to install. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a power-taking device based on maximum power point tracking. By installing the power-taking device at any position on the power line, stable power supply can be obtained by induction, thereby meeting the power supply requirements of the online monitoring device of the power line.

[0005] The technical solutions provided by this utility model are as follows:

[0006] A power supply device based on maximum power point tracking includes a rectifier and a capacitor connected in series with a current transformer, and also includes a maximum power tracker for obtaining the voltage and current of the capacitor and performing power tracking; the current transformer is equipped with a protector for switching its short-circuit / open-circuit state, and the maximum power tracker is also connected to the load and the protector respectively to supply power to the load and provide a control signal to the protector.

[0007] Furthermore, the maximum power tracker includes a voltage tracking module, a current tracking module, an arithmetic unit, a voltage control module and a current control module, as well as a protection output interface connected to the protector and a voltage output terminal for powering the load; the voltage tracking module is used to obtain the capacitor voltage in real time, and the current tracking module is used to obtain the capacitor current in real time; the arithmetic unit is used to calculate the real-time power and output the control signal to the protector through the protection output interface; the voltage control module and the current control module are connected to the arithmetic unit for controlling the output voltage and current.

[0008] Furthermore, the current transformer is single or multiple.

[0009] Preferably, the rectifier adopts a full-bridge rectifier circuit.

[0010] Preferably, the power extraction device is installed in a metal casing.

[0011] Beneficial effects of the utility model:

[0012] The device of the utility model is composed of several parts, including a current transformer, a rectifier, a capacitor, a maximum power tracker, and a protector. The maximum power tracker is the core component of the device. Its main function is to track the maximum power point output by the current transformer under different currents and stabilize it to operate at the maximum power point, ensuring that the current transformer always operates in the optimal state, and the actual efficiency is improved by an average of about 35%. The device of the utility model is installed on the power line and can flexibly choose to use a single or two current transformers, or multiple power supply groups in parallel to meet high-load power requirements according to the actual load requirements. Under high-load conditions, the number of front-end current transformers installed can be effectively reduced, or the volume and weight can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0014] Figure 1 This is a schematic diagram of the module composition of the power extraction device provided by one embodiment of the present utility model;

[0015] Figure 2 This is a circuit diagram of a CT that obtains energy and outputs a DC voltage, provided by an embodiment of the present utility model;

[0016] Figure 3 This is a schematic diagram of a power curve provided by an embodiment of the present utility model. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0018] This embodiment provides a power supply device based on maximum power point tracking, such as Figure 1 and Figure 2 As shown in the figure, it is mainly composed of CT (current transformer), protector, rectifier, capacitor and maximum power tracker. Its purpose is to obtain as much energy as possible under a small current.

[0019] The protector's function is to short-circuit the CT when needed. Its basic functions are: suppressing the voltage at the front end of the rectifier to prevent excessive voltage from burning out the rectifier; preventing the CT from being in an open-circuit state for extended periods. This can trigger rapid magnetic protection when current flows on the primary side, generating significant heat and potentially causing a primary cable failure; and controlling the DC voltage at the capacitor end. When the primary current is high, the load cannot consume the excess energy, causing the capacitor voltage to continue to rise, leading to breakdown. Once the protector operates, it limits the capacitor voltage to within a specified range.

[0020] The rectifier converts the AC voltage output by the CT into a DC voltage suitable for the circuit. Full-wave rectification is used here for high efficiency. The capacitor stores and filters the rectified signal, producing a DC voltage source. The maximum power point tracker (MPPT) tracks and locks the maximum power point (MPP), regulates the load voltage, limits the load current, and controls the output of the protector. The MPPT specifically includes a voltage tracking module, a current tracking module, an arithmetic unit (APU), a voltage control module, a current control module, a protection output interface connected to the protector, and a voltage output terminal for powering the load.

[0021] The voltage tracking module and current tracking module monitor the voltage and current values at the front-end (capacitor) input in real time, using the intermediate arithmetic unit to determine the real-time power. The arithmetic unit integrates the input voltage and current to obtain the real-time power and controls the output voltage and current to maintain maximum input power. Furthermore, if the input voltage or current exceeds a threshold, a control signal is immediately output through the protection output interface, triggering the protector to short-circuit the CT, bringing the input power back to normal.

[0022] The output control sequence is voltage control first, then current control. When the voltage is controlled at the output upper limit, the output current is gradually increased until it can no longer be increased. The system then analyzes the changes in input voltage and current to identify the maximum input power point, thereby maintaining power to the load. When the voltage is at its highest and the current is too low to power the load, the output voltage is actively lowered to the lower limit. In this process, the input maximum power point is again determined based on the changes in input voltage and current to maintain load operation. During the regulation process, if the output voltage and current reach the controllable upper limit but the input voltage continues to increase, the arithmetic unit outputs a control signal to the protection output port. The protection output port amplifies the signal and uses it to control the protector. The protector shorts the CT, preventing the input voltage and current from increasing, and the output relies on capacitor energy storage. When the input voltage drops back to the lower threshold, the protector reopens, charging the energy storage capacitor.

[0023] The power extraction device provided in this embodiment is a single board installed in an aluminum housing. To use it, first mate the CT with the device's connector to ensure a secure connection and prevent the CT from opening during installation. Then, open the CT's outer clamp and install the separated CT onto the cable. Once the cable is powered on, the device enters normal operation, and the voltage output terminal supplies the power required by the load.

[0024] The basic working principle of this device:

[0025] CT has the characteristic of converting current from the primary circuit. Using this characteristic, if a resistor is connected in series with the secondary circuit of the CT, a voltage will be generated across the resistor. The voltage across the resistor and the current flowing through it at this time are the actual power consumed by the resistor. The power consumed by the resistor varies with the resistance value. As the output voltage changes, the power also changes equivalently. Its power curve is as follows: Figure 3 shown. Figure 3 In the figure, Pmax represents the maximum output power point of the coil. In practice, it's difficult to accurately control the device to operate at this point. In practice, the output power fluctuates within a small range around Pmax to avoid prolonged operation in rising and falling power ranges. Voltages V1 and V2 are called the control return voltage and cutoff voltage, respectively. They provide a control reference point for the maximum power tracker. When voltage reaches V2, the CT input is limited, controlling the current to achieve maximum power output. As the voltage decreases, the power returns to the maximum power point. Conversely, when the voltage drops back to V1, the output voltage is limited, allowing the charging power to return to the maximum power point. The maximum power tracker's function is to find the CT's maximum output power point and operate it there. While the load power remains constant, the primary current can be reduced. This allows the device to achieve higher power without changing the primary current.

[0026] The internal working logic of this device:

[0027] When the CT operates, it forms a current source through the protector. After connecting the rectifier in series, it forms a semi-open circuit, generating an AC voltage across the rectifier. After full-bridge rectification, a DC voltage is generated across the capacitor. The DC voltage and outflow current across the capacitor are sampled and transmitted to the arithmetic unit (APU), which generates real-time power P. The APU controls the voltage and current supplied to the load so that the real-time power P at the capacitor remains above Pout on the power curve. The APU controls the input power P as follows: First, the APU adjusts the load voltage, preferably to its maximum value. At this point, the output current is gradually increased until the output voltage becomes unstable. The output current is then adjusted again until the power P at the capacitor reaches around Pmax and is maintained there. Secondly, the constant current method is used. When the device operates using the voltage method, the input power P continues to decrease until P ≤ Pout. The APU then locks the load current at that point and attempts to adjust the output voltage until the power P at the capacitor returns to above Pout.

[0028] Protection judgment process of the operator: Judgment of protection action, no matter whether the device operates in voltage method or current method logic, as long as the current and voltage at the output end are adjusted to the maximum value, the voltage at the capacitor end still exceeds the V2 value in the power curve, then a control voltage is given to the protector through the protection output port to make the internal part of the protector conductive and limit the output of the CT; Judgment of protection return, the current of the primary line gradually decreases, or the protector is in action, the voltage at the capacitor end will enter a downward trend, and the power P at the capacitor end will enter a downward stage at the same time, until the power P≤Pout, and the voltage at the capacitor end is lower than V1, the operator cancels the control voltage to the protector through the protection output port, so that the output of the CT is turned on.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of this application.

Claims

1. A power supply device based on maximum power point tracking, characterized in that: It includes a rectifier and a capacitor connected in series with a current transformer, and also includes a maximum power tracker for obtaining the voltage and current of the capacitor and performing power tracking; the current transformer is configured with a protector for switching its short-circuit / open-circuit state, and the maximum power tracker is also connected to the load and the protector respectively, for supplying power to the load and providing a control signal to the protector.

2. The power supply device based on maximum power point tracking according to claim 1, characterized in that: The maximum power tracker includes a voltage tracking module, a current tracking module, an arithmetic unit, a voltage control module, and a current control module, as well as a protection output interface connected to a protector and a voltage output terminal for powering a load; the voltage tracking module is used to obtain the capacitor voltage in real time, and the current tracking module is used to obtain the capacitor current in real time; the arithmetic unit is used to calculate the real-time power and output a control signal to the protector through the protection output interface; the voltage control module and the current control module are connected to the arithmetic unit to control the output voltage and current.

3. The power supply device based on maximum power point tracking according to claim 1, characterized in that: The current transformer may be single or multiple.

4. The power supply device based on maximum power point tracking according to claim 1, characterized in that: The rectifier adopts a full-bridge rectifier circuit.

5. The power supply device based on maximum power point tracking according to claim 1, characterized in that: The power taking device is installed in the metal shell.

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