Dual-voltage detection circuit used in BOOST circuit

Abstract

The utility model discloses a dual-voltage detection circuit used in a BOOST circuit. The dual-voltage detection circuit comprises a sampling resistor module, a voltage-frequency conversion module and an optical coupler isolation module. The sampling resistor module divides input and output voltages to be within 10V through a series resistor network; the voltage-frequency conversion module comprises two voltage-frequency conversion chips and converts the voltage signal after voltage division into a corresponding frequency signal; and the optical coupling isolation module adopts a dual-channel optical coupling chip to realize electrical isolation of frequency signals. According to the utility model, a voltage-frequency conversion scheme is adopted, so that the potential safety hazard caused by direct sampling in a traditional voltage division method is avoided, and the problem of insufficient precision caused by a 1V voltage division range is overcome. Meanwhile, safe transmission of signals is achieved through optical coupler isolation, and the reliability of the system is improved. According to the scheme, the measurement precision is guaranteed, meanwhile, the anti-interference capability is high, and the method is particularly suitable for being applied to a voltage detection scene of a high-power BOOST circuit.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power electronics, in particular to a double voltage detection circuit for BOOST circuit. BACKGROUND

[0002] As an important switching power supply converter, the real-time monitoring of the input and output voltage of BOOST circuit is crucial to ensure the stable operation of the system. Currently, the voltage detection methods commonly used in BOOST circuit have many limitations.

[0003] When using fixed voltage dividing resistor method for voltage detection, high voltage signal will be introduced into the control circuit under high voltage condition, which can easily cause system instability. At the same time, the voltage signal after voltage division usually only has about 1V, which significantly reduces the measurement accuracy, and there are great safety hazards in actual application.

[0004] Although the capacitor charging and discharging detection method avoids direct contact with high voltage end and improves measurement safety, its detection accuracy is poor. In actual application, due to the influence of capacitor parameter deviation, charging and discharging time error and other factors, it is difficult to obtain accurate voltage measurement results.

[0005] Although the special voltage sensor detection method has high measurement accuracy and good anti-interference performance, its cost is high, and in actual application, it often needs complex signal conditioning circuit, which increases the complexity and maintenance difficulty of the system. This method is mainly suitable for specific occasions with very high measurement accuracy requirements, and is difficult to be widely used in ordinary BOOST circuit.

[0006] The above-mentioned several commonly used detection methods either have safety hazards and insufficient accuracy, or have high cost and are difficult to promote, which cannot meet the requirements of safety, accuracy and cost of voltage detection in BOOST circuit. In the actual application of BOOST circuit, especially in high-power occasions, these problems are more prominent, which may affect the reliability and stability of the system. UTILITY MODEL CONTENTS

[0007] The utility model aims at providing a double voltage detection circuit for BOOST circuit, which aims at solving the problems of safety, accuracy and cost of voltage detection in the prior art.

[0008] To achieve the above-mentioned purpose, the utility model provides a double voltage detection circuit for BOOST circuit, which comprises a sampling resistor module, a voltage-to-frequency conversion module and an optocoupler isolation module.

[0009] The sampling resistance module is used for sampling and dividing the input voltage and the output voltage of the BOOST circuit; the voltage frequency conversion module is connected with the sampling resistance module and is used for converting the voltage signal after being divided into a frequency signal; and the optical coupling isolation module is connected with the voltage frequency conversion module and is used for electrically isolating the frequency signal.

[0010] Optionally, the sampling resistance module comprises a first sampling unit and a second sampling unit, wherein the first sampling unit is used for sampling a first voltage signal, and the second sampling unit is used for sampling a second voltage signal.

[0011] Optionally, the voltage frequency conversion module comprises a first voltage frequency conversion unit and a second voltage frequency conversion unit, and the first voltage frequency conversion unit and the second voltage frequency conversion unit are connected with the first sampling unit and the second sampling unit respectively.

[0012] Optionally, the first voltage frequency conversion unit and the second voltage frequency conversion unit each comprise a voltage frequency conversion chip, an input end of the voltage frequency conversion chip is connected with the corresponding sampling unit, and an output end of the voltage frequency conversion chip is connected with the optical coupling isolation module.

[0013] Optionally, the optical coupling isolation module comprises an optical coupling isolation chip, and the optical coupling isolation chip has two output paths and is used for outputting two isolated frequency signals.

[0014] Optionally, the sampling resistance module divides the input voltage and the output voltage to be within 10V.

[0015] Optionally, the output frequency of the voltage frequency conversion chip has a linear corresponding relationship with the input voltage.

[0016] Optionally, the voltage frequency conversion chip comprises a power supply end, a ground end, an input end and an output end.

[0017] The power supply end is connected with a power supply voltage and a power supply filter capacitor; the input end is connected with the output end of the sampling resistance module; and the output end is connected with the optical coupling isolation module through a voltage dividing resistor.

[0018] Compared with the prior art, the double voltage detection circuit for the BOOST circuit provided by the utility model adopts the technical scheme, the utility model divides the voltage through the sampling resistance module, then converts the voltage signal into a frequency signal through the voltage frequency conversion module, and finally realizes electrical isolation through the optical coupling isolation module, which not only effectively solves the safety hidden trouble in the traditional voltage dividing detection method, but also avoids the precision problem caused by direct sampling. Meanwhile, the scheme converts the voltage signal into a frequency signal for transmission, improves the anti-interference ability, and ensures the reliability of signal transmission.

[0019] By adopting the design of dividing the voltage to within 10V and using the voltage-to-frequency conversion chip to realize the linear conversion from voltage to frequency, the utility model discloses can guarantee the measurement accuracy, and the system cost is reduced obviously in addition, the design of two-way voltage detection makes the system can monitor the input and output voltage of BOOST circuit simultaneously, provides reliable data support for the stable operation and protection function of system. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is BOOST main circuit schematic diagram in the embodiment of the utility model;

[0021] Figure 2 It is a kind of double voltage detection circuit schematic diagram for BOOST circuit in the embodiment of the utility model. DETAILED DESCRIPTION

[0022] The utility model scheme will be described below in conjunction with schematic diagram, wherein the preferred embodiment of the utility model is shown, it should be understood that the utility model described herein can be modified by the person skilled in the art, and still realize the advantageous effect of the utility model. Therefore, the following description should be understood as extensive knowledge for the person skilled in the art, and not as the limitation of the utility model.

[0023] The serial number of component in this paper, for example, "first", "second" and the like, is only used to distinguish the described object, and does not have any order or technical meaning. And the "connection", "coupling" of the present application includes direct and indirect connection (coupling) without special statement. In the description of the utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, so it cannot be understood as a limitation of the utility model.

[0024] In the utility model, unless otherwise expressly specified and limited, the first feature is "on" or "under" the second feature. It can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature can be directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature can be directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0025] The utility model is described in more detail by way of example in the following paragraphs with reference to the drawings. The advantages and features of the utility model will be more apparent from the following description. It should be noted that the drawings are all very simplified and use non-precise scales, and are only used to facilitate and clarify the purpose of assisting in the description of the embodiments of the utility model.

[0026] The dual-voltage detection circuit of the utility model is mainly applied to a BOOST voltage-boosting circuit. Referring to the BOOST main circuit structure shown in Figure 1 The circuit is composed of an input rectification part, a main circuit part and an output filter part.

[0027] The input rectification part adopts a three-phase rectification bridge module APTDR90UX1601G. The module receives three-phase alternating current power input through three interfaces J1, J2 and J3, and realizes conversion from alternating current to direct current. The rectified direct current voltage is filtered by an electrolytic capacitor C11, effectively suppressing the ripple component of the input voltage.

[0028] The main circuit part constitutes a basic BOOST voltage-boosting topology structure, including a diode D1 (model STTH1512), an inductor L1 and a power switch Q1 (model IXFN32N120P). These components work cooperatively to realize voltage boosting: when the switch Q1 is turned on, the inductor L1 stores energy; when the switch is turned off, the inductor releases energy, which is superimposed with the input voltage, so that a higher voltage is obtained at the output end.

[0029] The output filter part adopts three parallel capacitors C8, C9 and C10, each with a capacitance of 0.047 μF. This parallel design can effectively reduce the equivalent series resistance and improve the filtering effect, ensuring the stability of the output voltage.

[0030] Referring to Figure 2 The dual-voltage detection circuit for a BOOST circuit provided by the utility model includes a sampling resistance module, a voltage-to-frequency conversion module and an optocoupler isolation module. The sampling resistance module is used to sample and divide the input voltage and the output voltage of the BOOST circuit; the voltage-to-frequency conversion module is connected with the sampling resistance module and is used to convert the divided voltage signal into a frequency signal; and the optocoupler isolation module is connected with the voltage-to-frequency conversion module and is used to electrically isolate the frequency signal.

[0031] The detection circuit is mainly used for detecting the input voltage and the output voltage in the BOOST circuit, and can realize safe acquisition and accurate transmission of the voltage signal.

[0032] Specifically, the sampling resistance module includes a first sampling unit and a second sampling unit, which are respectively used to sample 800 V and 500 V voltage signals.

[0033] The first sampling unit is composed of resistors R2, R3, R4, R5, R6, R7, R8, R1 and R10 in series and capacitor C3. R2 to R8 are all 47kΩ / 1W precision resistors, which can ensure sufficient voltage resistance and precision. R1 and R10 are used for final voltage sampling. Capacitor C3 is used to filter high-frequency interference and improve the stability of the sampling signal.

[0034] The second sampling unit is composed of resistors R14, R15, R16, R17, R18, R19, R20, R13 and R22 in series and capacitor C7. The symmetrical design of the sampling unit simplifies the circuit design and component selection, and facilitates maintenance and debugging.

[0035] Through the design of the voltage dividing network, the high-voltage signal can be divided to within 10V, which is higher than the traditional 1V voltage division, providing a larger signal amplitude and significantly improving the measurement accuracy. On the other hand, it remains within the safe voltage range, ensuring the safety of the subsequent circuit.

[0036] Further, the voltage-to-frequency conversion module adopts a dual-channel design, including two independent voltage-to-frequency conversion units: a first voltage-to-frequency conversion unit and a second voltage-to-frequency conversion unit.

[0037] The first voltage-to-frequency conversion unit uses voltage-to-frequency conversion chip U1, and the second voltage-to-frequency conversion unit uses voltage-to-frequency conversion chip U3.

[0038] In a specific example, the connection mode of the voltage-to-frequency conversion chip is as follows:

[0039] For voltage-to-frequency conversion chip U1, its 4-pin receives the voltage division signal from the sampling resistor module, 3-pin is grounded through resistor R9 for setting the conversion gain, 2-pin is directly grounded, and 1-pin is connected to test point TP1 as the output end and connected to 8-pin through resistors R12 and R11. At the same time, the output signal of 1-pin is connected to 2-pin of optocoupler isolation chip U2. 5-pin of U1 is connected to -5V power supply, 8-pin is connected to +12V power supply, and capacitor C1 is connected in parallel between 5-pin and 8-pin for power supply filtering. Capacitor C2 is connected in parallel between 6-pin and 7-pin for setting the conversion frequency.

[0040] The connection mode of voltage-to-frequency conversion chip U3 is similar to U1, its 4-pin receives the second voltage division signal, 3-pin is grounded through resistor R21, and the remaining connection relationship remains the same. This dual-channel voltage-to-frequency conversion design ensures that the two voltage signals can be detected and converted simultaneously, avoiding the delay and interference caused by time sequence switching.

[0041] In another specific example, the structure of the second voltage-to-frequency conversion unit is basically the same as the first unit, and the same model of AD654 chip (U3) is adopted.

[0042] The core principle of voltage-to-frequency conversion is to linearly convert a voltage signal into a frequency signal, and the conversion relationship follows the formula:

[0043] Fout = Vin / ((10V)(R1+R2)CT);

[0044] Where CT is the timing capacitor (C2 or C6), and R1+R2 is the total value of the timing resistor (R9 or R21). From the formula, it can be seen that the output frequency Fout is linearly related to the input voltage Vin, that is, for every unit increase in input voltage, the output frequency increases by a fixed value. By reasonably selecting the parameters of these components, the best conversion accuracy and linearity can be obtained.

[0045] Further, the optocoupler isolation module adopts an optocoupler isolation chip U2, and the specific connection mode is as follows: 1 pin is connected to the output signal of U1, 2 pin is connected to 1 pin of U1, 3 pin is connected to 1 pin of U3, 4 pin is connected to the output signal of U3. The 8 pin of U2 is connected to the isolated +5V power supply, the 5 pin is connected to the isolated ground, and the capacitor C4 is connected in parallel between the 5 pin and the 8 pin for filtering. The 7 pin and the 6 pin are used as output terminals, respectively outputting 800V and 500V corresponding frequency signals.

[0046] In summary, the design of the optocoupler isolation module not only realizes electrical isolation of the signal, but also has the following advantages: complete electrical isolation is achieved through photoelectric conversion, effectively preventing the influence of high voltage on the control circuit; high-speed optocouplers are used to ensure accurate transmission of frequency signals, almost without introducing phase delay; the dual-channel design allows two-way signals to be transmitted simultaneously, improving system response speed.

[0047] In one specific example, the voltage dividing resistor of the first sampling unit can adopt a 47kΩ / 1W specification, and the voltage dividing resistor of the second sampling unit can also adopt the same specification, which not only ensures the voltage dividing accuracy, but also ensures the reliability of the components. The voltage-to-frequency conversion chip can be selected from AD654 or other chips with similar functions, and the optocoupler isolation chip can be selected from ACFI-B641-560B or other devices with similar performance.

[0048] The voltage detection circuit of the utility model works based on the voltage-frequency conversion principle. First, the high voltage signal is divided to a safe level through a precision resistor network, then the voltage signal is converted to a frequency signal by using a voltage-to-frequency conversion chip, and finally the signal is isolated by an optocoupler and output to the control system. This detection scheme avoids the safety hazards of directly sampling high voltage, and improves the anti-interference performance through frequency signal transmission.

[0049] In practical application, the detection circuit working process of the utility model specifically includes:

[0050] Preparation work before system power on:

[0051] Check whether all power supply connections are correct;

[0052] Confirm the voltage division ratio of sampling resistance;

[0053] Verify the power supply voltage of the pressure-frequency conversion chip.

[0054] System debugging:

[0055] Use oscilloscope to monitor the pressure-frequency conversion output through TP1 and TP2 test points;

[0056] Check the linear relationship between output frequency and input voltage;

[0057] Verify the quality of the optocoupler isolated output signal.

[0058] Normal operation:

[0059] After the BOOST circuit starts, the detection circuit automatically starts working;

[0060] MCU calculates the actual voltage value by collecting the frequency signals of 7 pins and 6 pins;

[0061] According to the voltage value, the corresponding control strategy is adjusted.

[0062] Abnormal processing:

[0063] When the detected voltage exceeds the preset range, the system can alarm or take protective measures in time;

[0064] If the frequency is abnormal, the problem can be quickly located through the test point.

[0065] The voltage detection scheme adopted by the utility model has remarkable technical effects:

[0066] By dividing the high voltage to within 10V instead of within 1V of the traditional, the measurement accuracy is significantly improved;The pressure-frequency conversion mode avoids the safety hazards that may be caused by direct sampling;The safe transmission of signals is realized through optocoupler isolation, and the reliability of the system is improved.In addition, the cost of the scheme is greatly reduced compared with the sensor scheme, and has good engineering practicability.

[0067] Obviously, those skilled in the art can make various modifications and variations to the utility model without departing from the spirit and scope of the utility model. Thus, if these modifications and variations of the utility model fall within the scope of the utility model claims and their equivalent technologies, the utility model also intends to include these modifications and variations.

Claims

1. A dual voltage detection circuit for use in a BOOST circuit, characterized by, The application relates to a sampling resistor module, a voltage-to-frequency conversion module and an optical coupling isolation module. The sampling resistor module is used for sampling and dividing the input voltage and the output voltage of a BOOST circuit; the voltage-to-frequency conversion module is connected with the sampling resistor module and is used for converting the divided voltage signal into a frequency signal; and the optical coupling isolation module is connected with the voltage-to-frequency conversion module and is used for electrically isolating the frequency signal. The sampling resistor module comprises a first sampling unit and a second sampling unit, wherein the first sampling unit is used for sampling a first voltage signal, and the second sampling unit is used for sampling a second voltage signal.

2. The dual voltage detection circuit of claim 1, wherein, The voltage-to-frequency conversion module comprises a first voltage-to-frequency conversion unit and a second voltage-to-frequency conversion unit, and the first voltage-to-frequency conversion unit and the second voltage-to-frequency conversion unit are respectively connected with the first sampling unit and the second sampling unit.

3. The dual voltage detection circuit of claim 2, wherein, The first voltage-to-frequency conversion unit and the second voltage-to-frequency conversion unit both comprise a voltage-to-frequency conversion chip, the input end of the voltage-to-frequency conversion chip is connected with the corresponding sampling unit, and the output end of the voltage-to-frequency conversion chip is connected with the optical coupling isolation module.

4. The dual voltage detection circuit of claim 3, wherein, The optical coupling isolation module comprises an optical coupling isolation chip, and the optical coupling isolation chip has two-way output and is used for outputting two-way frequency signals after isolation.

5. The dual voltage detection circuit of claim 1, wherein, The sampling resistor module divides the input voltage and the output voltage to be within 10V.

6. The dual voltage detection circuit of claim 1, wherein, The output frequency of the voltage-to-frequency conversion chip has a linear corresponding relationship with the input voltage.

7. The dual voltage detection circuit of claim 4, wherein, The voltage-to-frequency conversion chip comprises a power supply end, a grounding end, an input end and an output end.

8. The dual voltage detection circuit of claim 4, wherein, The power supply end is connected with a power supply voltage and a power supply filter capacitor; the input end is connected with the output end of the sampling resistor module; and the output end is connected with the optical coupling isolation module through a dividing resistor. ​

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