Novel SVG power unit board card temperature sampling circuit

Abstract

The utility model discloses a novel SVG (Static Var Generator) power unit board card temperature sampling circuit, which belongs to the technical field of power electronics and comprises two IGBTs (Insulated Gate Bipolar Translator), the NTC resistor in each IGBT is connected with the corresponding common mode inductor, the voltage division circuit and the low-pass RC filter circuit in sequence and then connected to the in-phase input end of the corresponding operational amplifier, and the reverse input end and the output end of each operational amplifier are connected with each other, then serve as the input end of the second-order active low-pass filter and are connected with the second-order active low-pass filter. According to the NTC temperature sampling circuit, high-frequency signals in the temperature sampling circuit can be effectively filtered, stable direct-current voltage waveforms are output, and the stability of NTC temperature sampling data can be improved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and more specifically to a novel temperature sampling circuit for an SVG power unit board. Background Art

[0002] With the continued development of the national power grid and the increasing proportion of green energy, grid flicker and harmonics are seriously affecting the sustainable development of the grid. As the optimal solution for reactive power compensation, the sustainable development of SVG directly affects the quality of the grid.

[0003] SVG power modules typically use IGBTs as switching devices. The NTC resistor of the IGBT is built into the IGBT. Currently, when using a temperature sampling circuit to sample NTC temperature data, it is easily interfered with by high-frequency signals, causing fluctuations in the NTC temperature sampling.

[0004] Therefore, how to filter out high-frequency signals in the temperature sampling circuit has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the present invention provides a novel temperature sampling circuit for an SVG power unit board, which at least solves some of the technical problems in the background art.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A novel SVG power unit board temperature sampling circuit includes: two IGBTs, an NTC resistor in each IGBT is sequentially connected to a corresponding common-mode inductor, a voltage divider circuit, and a low-pass RC filter circuit, and then connected to the non-inverting input of the corresponding operational amplifier. The inverting input and output of each operational amplifier are interconnected and serve as the input of a second-order active low-pass filter, and are connected to the second-order active low-pass filter.

[0008] Preferably, the two IGBTs include a first IGBT and a second IGBT;

[0009] The NTC resistor in the first IGBT is connected in sequence to the first common-mode inductor, the first voltage divider circuit, and the first low-pass RC filter circuit.

[0010] The NTC resistor in the second IGBT is connected in sequence to the second common-mode inductor, the second voltage divider circuit, and the second low-pass RC filter circuit.

[0011] Preferably, the first voltage divider circuit includes a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is simultaneously connected to a 5V power supply and one end of the first capacitor, and the other end of the first capacitor is grounded; the other end of the first resistor is interconnected with one end of the second resistor, and after being interconnected, is connected to an output end of the first common-mode inductor; the other end of the second resistor is connected to the other output end of the first common-mode inductor, and the other end of the second resistor is simultaneously grounded.

[0012] Preferably, the second voltage divider circuit includes a fifth resistor, a sixth resistor and a fifth capacitor, wherein one end of the fifth resistor is simultaneously connected to a 5V power supply and one end of the fifth capacitor, and the other end of the fifth capacitor is grounded; the other end of the fifth resistor is interconnected with one end of the sixth resistor, and after being interconnected, is connected to an output end of the second common-mode inductor; the other end of the sixth resistor is connected to the other output end of the second common-mode inductor, and the other end of the sixth resistor is simultaneously grounded.

[0013] Preferably, the first low-pass RC filter circuit includes a third resistor, a first diode, a second diode, a second capacitor, and a third capacitor;

[0014] Among them, one end of the third resistor is simultaneously connected to the other end of the first resistor and one end of the second resistor in the first voltage divider circuit, and the other end of the third resistor is simultaneously connected to the positive electrode of the first diode, the negative electrode of the second diode, one end of the second capacitor, one end of the third capacitor and the non-inverting input terminal of the corresponding operational amplifier; the negative electrode of the first diode is connected to a 5V power supply; the positive electrode of the second diode, the other end of the second capacitor and the other end of the third capacitor are connected to each other and then connected to the other end of the second resistor in the first voltage divider circuit.

[0015] Preferably, the second low-pass RC filter circuit includes a seventh resistor, a third diode, a fourth diode, a sixth capacitor, and a seventh capacitor;

[0016] Among them, one end of the seventh resistor is simultaneously connected to the other end of the fifth resistor and one end of the sixth resistor in the second voltage divider circuit, and the other end of the seventh resistor is simultaneously connected to the positive electrode of the third diode, the negative electrode of the fourth diode, one end of the sixth capacitor, one end of the seventh capacitor and the non-inverting input terminal of the corresponding operational amplifier; the negative electrode of the third diode is connected to a 5V power supply; the positive electrode of the fourth diode, the other end of the sixth capacitor and the other end of the seventh capacitor are connected to each other and then connected to the other end of the sixth resistor in the second voltage divider circuit.

[0017] Preferably, two corresponding operational amplifiers and their matching resistors and diodes form a voltage comparison circuit. Specifically, the voltage comparison circuit includes a first operational amplifier, a second operational amplifier, a fourth resistor, a fifth diode, a sixth diode, and an eighth resistor.

[0018] Wherein, the inverting input terminal of the first operational amplifier is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to one end of the eighth resistor, and the other end of the eighth resistor is connected to the inverting input terminal of the second operational amplifier;

[0019] The output terminal of the first operational amplifier is connected to the negative terminal of the fifth diode, and the positive terminal of the fifth diode is connected to the other end of the fourth resistor; the output terminal of the second operational amplifier is connected to the negative terminal of the sixth diode, and the positive terminal of the sixth diode is connected to one end of the eighth resistor; at the same time, the other end of the fourth resistor and one end of the eighth resistor are connected to each other and then used as the input terminal of the second-order active low-pass filter.

[0020] Preferably, the second-order active low-pass filter includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, an eighth capacitor, a ninth capacitor, and a third operational amplifier;

[0021] Wherein, one end of the ninth resistor is connected to the input terminal of the second-order active low-pass filter, and the other end of the ninth resistor is simultaneously connected to one end of the tenth resistor and one end of the eighth capacitor; the other end of the tenth resistor is simultaneously connected to one end of the ninth capacitor and the non-inverting input terminal of the third operational amplifier, the other end of the ninth capacitor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is simultaneously connected to one end of the twelfth resistor and the inverting input terminal of the third operational amplifier, and the other end of the twelfth resistor is connected to the other end of the eighth capacitor.

[0022] Preferably, the first operational amplifier and the second operational amplifier both include operational amplifiers of model LMV324DR2G.

[0023] Preferably, the novel SVG power unit board temperature sampling circuit further includes an analog-to-digital conversion chip, and the output end of the second-order active low-pass filter is connected to the analog-to-digital conversion chip.

[0024] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a new SVG power unit board temperature sampling circuit, which has the following beneficial effects:

[0025] This invention has a simple structure and can effectively filter out high-frequency signals in the temperature sampling circuit of the SVG power unit board by using an RC filter circuit and a second-order active low-pass filter, outputting a stable DC voltage waveform and helping to improve the stability of NTC temperature sampling data. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 The attached figure is a schematic diagram of the temperature sampling circuit structure of the novel SVG power unit board provided by this utility model. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only 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 ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] This utility model discloses a novel temperature sampling circuit for an SVG power unit board, comprising: two IGBTs, wherein the NTC resistor in each IGBT is connected in sequence to the corresponding common-mode inductor, voltage divider circuit and low-pass RC filter circuit, and then connected to the non-inverting input terminal of the corresponding operational amplifier; the inverting input terminal and output terminal of each operational amplifier are interconnected and used as the input terminal of a second-order active low-pass filter, and connected to the second-order active low-pass filter.

[0030] In one specific embodiment, such as Figure 1 As shown, in the temperature sampling circuit of the new SVG power unit board, the NTC resistor in the first IGBT (IGBT1) is connected in sequence to the first common-mode inductor, the first voltage divider circuit, and the first low-pass RC filter circuit; the NTC resistor in the second IGBT (IGBT2) is connected in sequence to the second common-mode inductor, the second voltage divider circuit, and the second low-pass RC filter circuit.

[0031] Specifically, such as Figure 1As shown, the first voltage divider circuit consists of a first resistor R1, a second resistor R2, and a first capacitor C1. One end of the first resistor R1 is connected to both the 5V power supply and one end of the first capacitor C1, while the other end of the first capacitor C1 is grounded. The other end of the first resistor R1 is connected to one end of the second resistor R2, and after being connected, they are connected to one output terminal of the first common-mode inductor L1. The other end of the second resistor R2 is connected to the other output terminal of the first common-mode inductor L1, and the other end of the second resistor R2 is also grounded.

[0032] The second voltage divider circuit consists of a fifth resistor R5, a sixth resistor R6, and a fifth capacitor C5. One end of the fifth resistor R5 is connected to both the 5V power supply and one end of the fifth capacitor C5, while the other end of the fifth capacitor C5 is grounded. The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6, and this connection is then connected to one output terminal of the second common-mode inductor L2. The other end of the sixth resistor R6 is connected to the other output terminal of the second common-mode inductor L2, and the other end of the sixth resistor R6 is also grounded.

[0033] The first low-pass RC filter circuit includes a third resistor R3, a first diode D1, a second diode D2, a second capacitor C2, and a third capacitor C3. One end of the third resistor R3 is connected to the other end of the first resistor R1 and one end of the second resistor R2 in the first voltage divider circuit. The other end of the third resistor R3 is connected to the anode of the first diode D1, the cathode of the second diode D2, one end of the second capacitor C2, one end of the third capacitor C3, and the non-inverting input terminal of the corresponding operational amplifier U1A. The cathode of the first diode D1 is connected to a 5V power supply. The anode of the second diode D2, the other end of the second capacitor C2, and the other end of the third capacitor C3 are interconnected and then connected to the other end of R2 in the first voltage divider circuit.

[0034] The second low-pass RC filter circuit includes a seventh resistor R7, a third diode D3, a fourth diode D5, a sixth capacitor C6, and a seventh capacitor C7; wherein one end of the seventh resistor R7 is simultaneously connected to the other end of the fifth resistor R5 and one end of the sixth resistor R6 in the second voltage divider circuit, and the other end of the seventh resistor R7 is simultaneously connected to the anode of the third diode D3, the cathode of the fourth diode D4, one end of the sixth capacitor C6, one end of the seventh capacitor C7, and the non-inverting input terminal of the corresponding operational amplifier U1B; the cathode of the third diode D3 is connected to a 5V power supply; the anode of the fourth diode D4, the other end of the sixth capacitor C6, and the other end of the seventh capacitor C7 are connected to each other and then to the other end of R6 in the second voltage divider circuit.

[0035] Figure 1In this circuit, two corresponding operational amplifiers (U1A and U1B) and their associated resistors and diodes form a voltage comparator circuit. Specifically, the voltage comparator circuit includes a first operational amplifier U1A, a second operational amplifier U1B, a fourth resistor R4, a fifth diode D5, a sixth diode D6, and an eighth resistor R8. The inverting input of the first operational amplifier U1A is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is connected to the inverting input of the second operational amplifier U1B. The output of the first operational amplifier U1A is connected to the negative terminal of the fifth diode D5, and the positive terminal of the fifth diode D5 is connected to the other end of the fourth resistor R4. The output of the second operational amplifier U1B is connected to the negative terminal of the sixth diode D6, and the positive terminal of the sixth diode D6 is connected to one end of the eighth resistor R8. Simultaneously, the other end of the fourth resistor R4 and one end of the eighth resistor R8 are interconnected, serving as the input of a second-order active low-pass filter.

[0036] Figure 1 In this circuit, the second-order active low-pass filter (second-order active filter circuit) includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, an eighth capacitor C8, a ninth capacitor C9, and a third operational amplifier U1C. One end of the ninth resistor R9 is connected to the input terminal of the second-order active low-pass filter (the lead-out line after R4 and R8 are connected), and the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and one end of the eighth capacitor C8. The other end of the tenth resistor R10 is connected to one end of the ninth capacitor C9 and the non-inverting input terminal of the third operational amplifier U1C. The other end of the ninth capacitor C9 is connected to one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is connected to one end of the twelfth resistor R12 and the inverting input terminal of the third operational amplifier U1C. The other end of the twelfth resistor R12 is connected to the other end of the eighth capacitor C8.

[0037] Figure 1 In the middle, the output terminal of the second-order active low-pass filter (the output terminal of the third operational amplifier U1C) is also connected to the analog-to-digital converter chip, which is used to convert analog signals into digital signals and for subsequent data processing.

[0038] In the above embodiment, both the operational amplifiers U1A and U1B in the voltage comparison circuit can be an operational amplifier of model LMV324DR2G.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0040] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel SVG power unit board temperature sampling circuit, characterized in that: include: Two IGBTs, the NTC resistor in each IGBT is connected in sequence with the corresponding common-mode inductor, the voltage divider circuit and the low-pass RC filter circuit and then connected to the in-phase input terminal of the corresponding operational amplifier, the inverting input terminal and the output terminal of each operational amplifier are connected to each other as the input terminal of the second-order active low-pass filter and are connected to the second-order active low-pass filter.

2. The novel SVG power unit board temperature sampling circuit according to claim 1 is characterized in that: The two IGBTs include a first IGBT and a second IGBT; Wherein, the NTC resistor in the first IGBT is connected to the first common mode inductor, the first voltage divider circuit, and the first low-pass RC filter circuit in sequence; The NTC resistor in the second IGBT is connected to the second common-mode inductor, the second voltage divider circuit, and the second low-pass RC filter circuit in sequence.

3. The novel SVG power unit board temperature sampling circuit according to claim 2 is characterized in that: The first voltage divider circuit includes a first resistor, a second resistor and a first capacitor, wherein one end of the first resistor is simultaneously connected to a 5V power supply and one end of the first capacitor, and the other end of the first capacitor is grounded; the other end of the first resistor is interconnected with one end of the second resistor, and after being interconnected, is connected to an output end of a first common-mode inductor; the other end of the second resistor is connected to the other output end of the first common-mode inductor, and the other end of the second resistor is simultaneously grounded.

4. The novel SVG power unit board temperature sampling circuit according to claim 2 is characterized in that: The second voltage-dividing circuit includes a fifth resistor, a sixth resistor and a fifth capacitor, wherein one end of the fifth resistor is connected to a 5V power supply and one end of the fifth capacitor at the same time, and the other end of the fifth capacitor is grounded; the other end of the fifth resistor is connected to one end of the sixth resistor, and after being connected to each other, they are connected to an output end of the second common-mode inductor; the other end of the sixth resistor is connected to the other output end of the second common-mode inductor, and the other end of the sixth resistor is grounded at the same time.

5. The novel SVG power unit board temperature sampling circuit according to claim 3 is characterized in that: The first low-pass RC filter circuit includes a third resistor, a first diode, a second diode, a second capacitor and a third capacitor; Among them, one end of the third resistor is simultaneously connected to the other end of the first resistor and one end of the second resistor in the first voltage divider circuit, and the other end of the third resistor is simultaneously connected to the positive electrode of the first diode, the negative electrode of the second diode, one end of the second capacitor, one end of the third capacitor and the non-inverting input terminal of the corresponding operational amplifier; the negative electrode of the first diode is connected to a 5V power supply; the positive electrode of the second diode, the other end of the second capacitor and the other end of the third capacitor are connected to each other and then connected to the other end of the second resistor in the first voltage divider circuit.

6. The novel SVG power unit board temperature sampling circuit according to claim 4 is characterized in that: The second low-pass RC filter circuit includes a seventh resistor, a third diode, a fourth diode, a sixth capacitor and a seventh capacitor; Among them, one end of the seventh resistor is simultaneously connected to the other end of the fifth resistor and one end of the sixth resistor in the second voltage divider circuit, and the other end of the seventh resistor is simultaneously connected to the positive electrode of the third diode, the negative electrode of the fourth diode, one end of the sixth capacitor, one end of the seventh capacitor and the non-inverting input terminal of the corresponding operational amplifier; the negative electrode of the third diode is connected to a 5V power supply; the positive electrode of the fourth diode, the other end of the sixth capacitor and the other end of the seventh capacitor are connected to each other and then connected to the other end of the sixth resistor in the second voltage divider circuit.

7. The novel SVG power unit board temperature sampling circuit according to claim 1 is characterized in that: Two corresponding operational amplifiers and their matching resistors and diodes form a voltage comparison circuit. Specifically, the voltage comparison circuit includes a first operational amplifier, a second operational amplifier, a fourth resistor, a fifth diode, a sixth diode and an eighth resistor; Wherein, the inverting input terminal of the first operational amplifier is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to one end of the eighth resistor, and the other end of the eighth resistor is connected to the inverting input terminal of the second operational amplifier; The output end of the first operational amplifier is connected to the cathode of the fifth diode, and the anode of the fifth diode is connected to the other end of the fourth resistor; the output end of the second operational amplifier is connected to the cathode of the sixth diode, and the anode of the sixth diode is connected to one end of the eighth resistor; at the same time, the other end of the fourth resistor and one end of the eighth resistor are connected to each other and then connected to the second-order active low-pass filter as the input end of the second-order active low-pass filter.

8. The novel SVG power unit board temperature sampling circuit according to claim 1 is characterized in that: The second-order active low-pass filter includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, an eighth capacitor, a ninth capacitor and a third operational amplifier; Among them, one end of the ninth resistor is connected to the input end of the second-order active low-pass filter, and the other end of the ninth resistor is simultaneously connected to one end of the tenth resistor and one end of the eighth capacitor; the other end of the tenth resistor is simultaneously connected to one end of the ninth capacitor and the non-inverting input end of the third operational amplifier, the other end of the ninth capacitor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is simultaneously connected to one end of the twelfth resistor and the inverting input end of the third operational amplifier, and the other end of the twelfth resistor is connected to the other end of the eighth capacitor.

9. The novel SVG power unit board temperature sampling circuit according to claim 7 is characterized in that: The first operational amplifier and the second operational amplifier both include operational amplifiers of model LMV324DR2G.

10. The novel SVG power unit board temperature sampling circuit according to claim 1, characterized in that: It also includes an analog-to-digital conversion chip, and the output end of the second-order active low-pass filter is connected to the analog-to-digital conversion chip.

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