Optical feedback power supply circuit

Abstract

The utility model discloses an optical feedback power supply circuit, which belongs to the field of photovoltaic power supply circuits and comprises a starting circuit, a control circuit, an output circuit, a feedback circuit and an adjusting circuit. The output end of the starting circuit is connected with the control circuit, the control circuit outputs to the output circuit after running and provides numerical values for the feedback circuit, the feedback circuit feeds back the corresponding numerical values after receiving the corresponding numerical values, the adjusting circuit sends the adjusted information to the control circuit after adjusting according to information of the feedback circuit, and the control circuit runs in sequence. And the required value is output to the output circuit.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power supply technology, specifically to a light feedback power supply circuit. Background Technology

[0002] Against the backdrop of the accelerated global energy transition to clean energy, photovoltaic (PV) power generation, as a crucial component of sustainable energy, is experiencing unprecedented rapid industrial expansion. This booming development places increasingly stringent demands on the performance and accuracy of PV testing equipment. As the core power source for these devices, the stability, reliability, and functional versatility of the power supply directly determine the accuracy and reliability of the test results.

[0003] Globally, the DC power supply market is experiencing robust and sustained growth. According to data from authoritative market research institutions, the global DC power supply market has steadily increased at an average annual growth rate of 6% over the past five years, and is projected to maintain a growth rate of over 8% in the next five years (as predicted by MarketsandMarkets, Grand View Research, and other institutions). This growth is primarily driven by strong demand for high-performance power supplies in various sectors such as industrial automation, new energy, and communications. Leading international power supply companies, leveraging their deep technological expertise and advanced R&D capabilities, dominate the high-precision, high-stability power supply market, while domestic companies lag significantly behind in core technologies, product performance, and market share.

[0004] Problems with existing photovoltaic power sources:

[0005] Insufficient Current Stability: Precise current output is crucial for ensuring accurate test results during photovoltaic (PV) testing. However, existing PV power supplies perform poorly in terms of current stability, failing to meet the stringent requirements of high-precision testing. For example, traditional PV power supplies often experience output current fluctuations exceeding ±30% during long-term operation, and even exceeding ±50% under extreme conditions. This undoubtedly introduces significant errors for applications requiring precise current control, such as PV cell performance testing and PV inverter efficiency testing, severely impacting the reliability and comparability of test results.

[0006] Significant fluctuations during mode switching: In practical applications, photovoltaic testing often requires switching between constant current mode and constant light intensity mode. However, existing power supplies exhibit significant fluctuations in current and light intensity during mode switching, leading to instability in the testing process. For example, when switching from constant current mode to constant light intensity mode, the fluctuation range of light intensity may reach ±20% to ±50%, and even higher in extreme scenarios. This not only prolongs testing time and reduces testing efficiency but may also cause deviations in test data, affecting the accurate evaluation of photovoltaic product performance.

[0007] Feedback control is susceptible to interference: Traditional power supplies typically use a shunt to collect voltage for feedback control, a method with significant drawbacks. The resistance value of the shunt drifts with temperature changes, leading to inaccurate voltage signals and affecting the power supply's output stability. In actual testing, due to temperature drift, the error in the power supply's output current can typically reach ±1% to ±5% (in typical designs), and in extreme cases, may exceed ±10%, severely impacting the accuracy of test results.

[0008] Insufficient Functional Integration and Customization: With the continuous development of the photovoltaic industry, users' functional requirements for power supplies are becoming increasingly diversified and personalized. However, existing photovoltaic power supplies have significant shortcomings in terms of functional integration and customization. Most power supplies only have basic voltage and current regulation functions, failing to meet users' needs for complex programming functions such as step, ladder, gradual, and function-based settings. Furthermore, in terms of communication and interaction with host computers, existing power supplies lack rich and flexible interfaces and protocols, making it difficult to achieve fully customized parameter settings and function configurations, and thus unable to adapt to the specific needs of different users.

[0009] Limited Protection Performance: Photovoltaic testing environments are complex and variable, and power supplies may face threats from various abnormal conditions such as overvoltage, overcurrent, and overtemperature. Existing photovoltaic power supplies have certain limitations in terms of protection performance; the response speed and accuracy of their overvoltage, overcurrent, and overtemperature protection functions need improvement. In practical applications, inadequate protection measures may damage the power supply and the equipment under test, causing unnecessary economic losses to users.

[0010] In summary, existing photovoltaic power supplies suffer from numerous problems in stability, feedback control, functional integration, and customization, severely hindering the development of photovoltaic testing technology and the improvement of photovoltaic product quality. Therefore, developing a dedicated photovoltaic power supply with high stability, high-precision feedback control, rich functional integration, and full customization capabilities is both an urgent practical need and of significant strategic importance. Summary of the Invention

[0011] The purpose of this invention is to provide an optical feedback power supply circuit that solves the problems of temperature drift, current fluctuation and unstable mode switching through optical feedback mechanism and structural optimization, thereby improving the stability and reliability of power output.

[0012] Technical solution

[0013] To achieve the above objectives, the present invention adopts the following technical solution: an optical feedback power supply circuit, comprising: a start-up circuit 101, a control circuit 102, an output circuit 103, a feedback circuit 104, and an adjustment circuit 105.

[0014] The startup circuit 101 includes a power input and an output filter. The input terminal of the power input is connected to the power supply terminal, and the output terminal of the power input is connected to the input terminal of the output filter to filter out noise interference at the power input terminal and ensure the stability of the initial current. The output terminal of the output filter is connected to the input terminal of the control circuit 102.

[0015] The control circuit 102 includes a soft starter, a PFC circuit, a MOSFET, a main control circuit, and a signal driver. The input terminal of the soft starter is connected to the output terminal of the output filter and the output terminal of the main control circuit. The output terminal of the soft starter is connected to the input terminal of the PFC circuit to suppress inrush current during startup. The PFC circuit is used to improve the power factor and reduce harmonic interference. Its input terminal is connected to the output terminal of the soft starter and the output terminal of the signal driver. The MOSFET adopts a full-bridge topology, with one end of its input terminal connected to the output terminal of the PFC circuit and the other end connected to the output terminal of the signal driver. At the output end, the output terminal of the MOS transistor is connected to the input terminal of the output circuit 103. The input terminal of the main control circuit is connected to the output terminal of the feedback circuit 104 and the output terminal of the adjustment circuit 105, and is used to receive feedback signals, issue adjustment commands, and receive the adjusted content. The output terminal of the main control circuit is connected to the input terminal of the signal drive and the input terminal of the soft start. The output terminal drives the signal drive module through a PWM signal (frequency of 100kHz). After receiving the signal from the main control circuit, the input terminal of the signal drive is connected to the PFC circuit and the MOS transistor respectively to control its operation.

[0016] The output circuit 103 includes an isolation step-up transformer, an output rectifier, an output filter, a voltage display, a current display, and a load output. The input terminal of the isolation step-up transformer is connected to the output terminal of the MOSFET. The isolation step-up transformer, the output rectifier, and the output filter are connected in series. The output terminal of the output filter is simultaneously connected to the input terminals of the output load, the voltage display, the current display, the voltage feedback, and the current feedback. The output load consists of a 4-inch LCD screen (touchscreen) and a button function area. The displayed content is clear and eye-catching, including voltage and current set values, voltage and current measured values, power calculation values, function menus, etc. The button function area includes an input ON / OFF switch, V-set / I-set / Output buttons, numeric keys, and a rotary knob for adjustment. The voltage display unit and the current display unit monitor the output voltage and current in real time, and the data can be displayed on the screen (model LCD1602).

[0017] The feedback circuit 104 includes current feedback, voltage feedback, and optical feedback. The input terminals of the voltage feedback and current feedback are connected to the output filter terminal, and the signals are acquired through precision voltage divider resistors (accuracy ±0.1%). The output terminals of the voltage feedback, current feedback, and optical feedback are connected to the input terminal of the main control circuit. The optical feedback receives the photocurrent feedback signal from the xenon lamp after irradiation and converts it into a voltage signal through a series low-temperature drift high-precision resistor (temperature drift coefficient ≤10ppm / ℃). The voltage feedback signal is then fed back to the main control circuit. The main control circuit dynamically adjusts the PWM duty cycle according to the light intensity to achieve a linear proportional relationship between the current and the light intensity, thereby suppressing the influence of temperature drift.

[0018] The adjustment circuit 105 includes a protection circuit, voltage adjustment, current adjustment, and host computer communication. The output terminals of the protection circuit, voltage adjustment, current adjustment, and host computer communication are connected to the input terminal of the main control circuit.

[0019] The beneficial effects of this utility model are:

[0020] 1. The power input adopts the most advanced PFC method, which greatly improves the power input efficiency and source effect.

[0021] 2. The output signal adopts PWM (square wave pulse width modulation signal) control mode, and the power section uses MOSFET as H-bridge control, with a switching frequency of up to 100kHz, reducing power frequency interference by 90%.

[0022] 3. The transformer works by full-wave rectification combined with an LC filter circuit. Its function is to reduce ripple and noise.

[0023] 4. Optical Feedback: After the xenon lamp illuminates the optical feedback device, a feedback signal is sent to it. The current signal fed back from the light is converted into a voltage signal by connecting a low-temperature drift, high-precision resistor in series. This allows the current to be adjusted according to the real-time light intensity. Higher light intensity results in a larger current, and the current is directly proportional to the light intensity, thus ensuring high current stability. This avoids the poor current stability caused by the temperature drift of the shunt when using voltage sampling for feedback.

[0024] 5. It integrates overvoltage / overcurrent protection and host computer communication functions, supports complex testing scenarios, and adapts to the diverse needs of the photovoltaic industry. Attached Figure Description

[0025] Figure 1 This is a simplified diagram of the power supply circuit structure for this practical application.

[0026] Figure 2 This is a schematic diagram of the optical feedback power supply circuit for this practical application.

[0027] In the diagram: 101. Start-up circuit, 102. Control circuit, 103. Output circuit, 104. Feedback circuit, 105. Adjustment circuit. Detailed Implementation

[0028] The following will refer to the appendix in the embodiments of this utility model. Figure 1 The technical solutions in the embodiments of this utility model will be clearly and completely described below. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this utility model.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0030] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0031] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0032] Against the backdrop of the accelerated global energy transition to clean energy, photovoltaic (PV) power generation, as a crucial component of sustainable energy, is experiencing unprecedented rapid industrial expansion. This booming development places increasingly stringent demands on the performance and accuracy of PV testing equipment. As the core power source for these devices, the stability, reliability, and functional versatility of the power supply directly determine the accuracy and reliability of the test results.

[0033] However, existing photovoltaic power supplies often have the following problems: 1. Insufficient current stability, 2. Large fluctuations during mode switching, susceptibility to interference in feedback control, insufficient functional integration and customization, and limited protection performance.

[0034] To address the aforementioned issues, embodiments of this utility model provide a light feedback power supply circuit. The input current is filtered through a startup circuit 101, and current stability is improved through a control circuit 102, a feedback circuit 104, and an adjustment circuit 105, thereby enhancing power supply protection performance and improving anti-interference capabilities. Furthermore, this application adds a light feedback module, which uses a low-temperature drift, high-precision resistor connected in series with the current signal fed back from the light feedback to convert it into a voltage signal. This allows for adjustment of the current based on the real-time light intensity; higher light intensity results in a larger current, and the current is directly proportional to the light intensity, ensuring high current stability. This avoids the poor current stability caused by the temperature drift of the shunt when using voltage sampling for feedback.

[0035] Specifically, such as Figure 1-2 As shown, this utility model provides a specific embodiment of an optical feedback power supply circuit, including: a startup circuit 101, a control circuit 102, an output circuit 103, a feedback circuit 104, and an adjustment circuit 105.

[0036] like Figure 2 As shown, the startup circuit 101 includes a power input and an output filter. The input terminal of the power input is connected to the power supply terminal, and the output terminal of the power input is connected to the input terminal of the output filter. The output filter uses an LC filter to filter out noise interference from the power input terminal to ensure the stability of the initial current. The output terminal of the output filter is connected to the input terminal of the control circuit 102.

[0037] like Figure 2 As shown, the control circuit 102 includes a soft starter, a PFC circuit, a MOSFET, a main control circuit, and a signal driver. The input of the soft starter is connected to the output of the output filter and the output of the main control circuit. The output of the soft starter is connected to the input of the PFC circuit to suppress inrush current during startup. The PFC circuit is used to improve the power factor and reduce harmonic interference. Its input is connected to the output of the soft starter and the output of the signal driver. The MOSFET adopts a full-bridge topology, with one end connected to the output of the PFC circuit and the other end connected to the output of the signal driver. The output of the MOSFET is connected to the input of the output circuit 103. The input of the main control circuit is connected to the output of the feedback circuit 104 and the output of the adjustment circuit 105, used to receive feedback signals, issue adjustment commands, and receive the adjusted content. The output of the main control circuit is connected to the input of the signal driver and the input of the soft starter. The output drives the signal driver module through a PWM signal (frequency 100kHz). After receiving the signal from the main control circuit, the input of the signal driver is connected to the PFC circuit and the MOSFET respectively to control their operation.

[0038] like Figure 2As shown, the output circuit 103 includes an isolation step-up transformer, output rectification, output filtering, voltage display, current display, and load output. The input terminal of the isolation step-up transformer is connected to the output terminal of the MOSFET. The isolation step-up transformer, output rectification, and output filtering are connected in series. The output terminal of the output filter is simultaneously connected to the input terminals of the output load, voltage display, current display, voltage feedback, and current feedback. The output load consists of a 4-inch LCD screen (touchscreen) and a button function area. The displayed content is clear and eye-catching, including voltage and current set values, voltage and current measured values, power calculation values, function menus, etc. The button function area includes an input ON / OFF switch, V-set / I-set / Output buttons, numeric keys, and a rotary knob for adjustment. The voltage display unit and current display unit monitor the output voltage and current in real time, and the data can be displayed on the screen (model LCD1602).

[0039] like Figure 2 As shown, the feedback circuit 104 includes current feedback, voltage feedback, and optical feedback. The input terminals of voltage feedback and current feedback are connected to the output filter terminal, and the signals are acquired through precision voltage divider resistors (accuracy ±0.1%). The output terminals of voltage feedback, current feedback, and optical feedback are connected to the input terminal of the main control circuit. The optical feedback receives the photocurrent feedback signal from the xenon lamp after irradiation and converts it into a voltage signal through a series low-temperature drift high-precision resistor (temperature drift coefficient ≤10ppm / ℃), which is then fed back to the main control circuit. The main control circuit dynamically adjusts the PWM duty cycle according to the light intensity to achieve a linear proportional relationship between current and light intensity, thereby suppressing the influence of temperature drift.

[0040] like Figure 2 As shown, the adjustment circuit 105 includes a protection circuit, voltage adjustment, current adjustment, and host computer communication. The output terminals of the protection circuit, voltage adjustment, current adjustment, and host computer communication are connected to the input terminal of the main control circuit. The host computer communication module supports the RS485 protocol. When overvoltage (>30V), overcurrent (>5A), or overtemperature (>50℃) is detected, the protection circuit immediately cuts off the MOSFET drive signal and issues an alarm via the display screen.

[0041] According to another embodiment of this utility model, the optical feedback board can also be replaced with a photodiode array. The power supply circuit after replacement has higher sensitivity, lower noise, wider linear range, etc., and can also perform parallel detection of optical signals at different positions to obtain spatial distribution information of optical signals.

[0042] According to another embodiment of this utility model, the optical feedback board can be replaced with a fiber optic transmission type optical feedback power supply circuit. The xenon lamp light source is transmitted to the remote optical feedback board through a multimode optical fiber. Collimating lenses are configured at both ends of the optical fiber to ensure efficient coupling of the optical signal. The output signal of the optical feedback board is amplified by a low-noise operational amplifier (model OPA2188) and then converted by a low-temperature drift resistor to reduce signal transmission loss. At the same time, a second-order Butterworth low-pass filter (cutoff frequency 1kHz) is added to the feedback circuit to suppress high-frequency noise, further reducing current fluctuation to ±0.2%. In this embodiment, the fiber optic transmission isolates electromagnetic interference. Combined with signal amplification and filtering, the feedback accuracy is significantly improved, making it suitable for environments with high electromagnetic interference.

[0043] The above description is only a preferred embodiment of the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A light feedback power supply circuit, characterized in that... include: Start-up circuit (101), control circuit (102), output circuit (103), feedback circuit (104), adjustment circuit (105); The startup circuit (101) includes a power input and an output filter. The input terminal of the power input is used to connect to the power supply terminal, the output terminal of the power input is connected to the input terminal of the output filter, and the output terminal of the output filter is connected to the input terminal of the control circuit (102). The control circuit (102) includes a soft starter, a PFC circuit, a MOS transistor, a main control circuit, and a signal driver. The input terminal of the soft starter is connected to the output terminal of the output filter and the output terminal of the main control circuit. The output terminal of the soft starter is connected to the input terminal of the PFC circuit. The input terminal of the PFC circuit is connected to the output terminal of the soft starter and the output terminal of the signal driver. The input terminal of the MOS transistor is connected to the output terminal of the PFC circuit and the output terminal of the signal driver. The output terminal of the MOS transistor is connected to the input terminal of the output circuit (103). The input terminal of the main control circuit is connected to the output terminal of the feedback circuit (104) and the output terminal of the adjustment circuit (105). The output terminal of the main control circuit is connected to the input terminal of the signal driver and the input terminal of the soft starter. After receiving the signal from the main control circuit, the output terminal of the signal driver is connected to the output terminals of the PFC circuit and the MOS transistor respectively to control their operation. The output circuit (103) includes an isolation step-up transformer, an output rectifier, an output filter, a voltage display, a current display, and a load output. The input terminal of the isolation step-up transformer is connected to the output terminal of the MOS transistor. The isolation step-up transformer, the output rectifier, and the output filter are connected in series. The output terminal of the output filter is also connected to the input terminal of the load output, the voltage display, the current display, and the feedback circuit (104). The load output, the voltage display, and the current display are responsible for outputting corresponding information. The feedback circuit (104) includes current feedback, voltage feedback and optical feedback. The input terminals of the voltage feedback and current feedback are connected to the output filter output terminal. The output terminals of the voltage feedback, current feedback and optical feedback are connected to the input terminal of the main control circuit. The optical feedback receives the feedback signal given after the xenon lamp is irradiated, converts it into a voltage signal through a series resistor, and then feeds it back to the main control circuit. The adjustment circuit (105) includes a protection circuit, voltage adjustment, current adjustment and host computer communication. The output terminals of the protection circuit, voltage adjustment, current adjustment and host computer communication are connected to the input terminal of the main control circuit.

2. The optical feedback power supply circuit according to claim 1, characterized in that, The optical feedback receives a photocurrent feedback signal from the xenon lamp after irradiation. The photocurrent feedback signal is connected in series with a low-temperature drift high-precision resistor to convert it into a voltage signal before being fed back to the main control circuit.

3. The optical feedback power supply circuit according to claim 1, characterized in that, The isolation step-up transformer operates on the principle of full-wave rectification combined with an LC filter circuit.

4. The optical feedback power supply circuit according to claim 1, characterized in that, The main control circuit outputs a square wave pulse width modulation signal control method.

5. The optical feedback power supply circuit according to claim 1, characterized in that, The MOS transistor is used for H-bridge control.

6. The optical feedback power supply circuit according to claim 1, characterized in that, The optical feedback board is a photodiode array.

7. The optical feedback power supply circuit according to claim 1, characterized in that, The optical feedback board is an optical fiber transmission type optical feedback power supply circuit.

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