Detection device and frequency converter structure

Abstract

The utility model provides a detection device and a frequency converter structure, and the device comprises a sampling module which is electrically connected with a first phase of a to-be-detected circuit, and is electrically connected with a second phase of the to-be-detected circuit; the sampling module outputs a sampling electric signal according to the electric signal of the first phase and the electric signal of the second phase; and the detection module is connected with the sampling module so as to receive the sampling electric signals, and the sampling module compares the sampling electric signals so as to output square wave signals according to the sampling electric signals. The detection device provided by the utility model solves the technical problem that the detected frequency of the frequency converter is inaccurate in the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit detection, in particular to a detection device and an inverter structure. Background Art

[0002] High-power photovoltaic centrifuges are generally applied to scenarios such as large factories, stadiums, hospitals, etc. The common characteristics of such scenarios are that there are many industrial-grade electrical equipment, large power, and high load, which will lead to many harmonic interferences in the factory power grid, poor power quality, and a complex electromagnetic field environment for high-power photovoltaic centrifuges. Therefore, it will affect the grid-side frequency detection function of the photovoltaic inverter used in high-power photovoltaic centrifuges.

[0003] At present, there are some technical solutions with certain anti-interference capabilities. However, in the above application scenarios, the effective anti-interference capabilities in such high-interference environments are poor, and some spikes caused by electromagnetic interference will be detected as frequency counts, which results in the detected frequency being higher than the actual frequency. When the detected frequency becomes higher without the actual frequency increasing, the system will wrongly perform grid-side frequency abnormal protection at this time. This causes problems such as air conditioner shutdown, resulting in economic losses such as factory production stoppage, project delay, workpiece damage, and forced closure of stadiums.

[0004] Therefore, the existing technology needs to be further developed. Summary of the Utility Model

[0005] The purpose of the utility model is to overcome the above technical deficiencies and provide a detection device and an inverter structure to solve the technical problem that the frequency of the detected inverter is inaccurate in related technologies.

[0006] To achieve the above technical purpose, the utility model adopts the following technical solutions: A detection device is provided, including: a sampling module, the sampling module is electrically connected to the first phase of the circuit to be detected, and the sampling module is electrically connected to the second phase of the circuit to be detected; the sampling module outputs a sampling electrical signal according to the electrical signals of the first phase and the second phase; a detection module, the detection module is connected to the sampling module to receive the sampling electrical signal, and the sampling module compares the sampling electrical signal to output a square wave signal according to the sampling electrical signal.

[0007] Further, the sampling module includes: a sampling component, the sampling component is respectively connected to the first phase and the second phase, and the sampling component outputs the sampling electrical signal according to the voltage difference between the first phase and the second phase.

[0008] Further, the sampling module includes: a first sampling circuit, one end of the first sampling circuit is connected to the first phase, and the other end of the first sampling circuit is connected to the sampling component; a first filter capacitor C2, the first filter capacitor C2 is connected in parallel with the first sampling circuit; a first filter resistor R4, the first filter resistor R4 is connected in parallel with the first filter capacitor C2.

[0009] Further, the sampling module includes: a second sampling circuit, one end of the second sampling circuit is connected to the second phase, and the other end of the second sampling circuit is connected to the sampling component; a second filter capacitor C1, the second filter capacitor C1 is connected in parallel with the second sampling circuit; a second filter resistor R3, the second filter resistor R3 is connected in parallel with the second filter capacitor C1.

[0010] Further, a first proportional resistor R1 is provided on the first sampling circuit; a second proportional resistor R2 is provided on the second sampling circuit; the ratio of the resistance value of the first proportional resistor R1 to the resistance value of the first filter resistor R4 is equal to the ratio of the resistance value of the second proportional resistor R2 to the resistance value of the second filter resistor R3.

[0011] Further, the detection module includes: a first comparison circuit, the first comparison circuit is connected to the sampling module to receive the sampled electrical signal; the first comparison circuit outputs a first comparison electrical signal according to the sampled electrical signal; a detection component, the detection component is connected to the first comparison circuit to receive the first comparison electrical signal; a second comparison circuit, the second comparison circuit is connected to the detection component to output a second comparison electrical signal to the detection component; wherein, after the detection component compares the first comparison electrical signal and the second comparison electrical signal, it outputs the square wave signal.

[0012] Further, a first voltage-dividing resistor R7 and a second voltage-dividing resistor R8 are provided on the first comparison circuit, and the detection component is connected to the circuit between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; the first comparison electrical signal is the voltage value at the midpoint of the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; a third voltage-dividing resistor R9 and a fourth voltage-dividing resistor R10 are provided on the second comparison circuit, and the detection component is connected to the circuit between the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; the second comparison electrical signal is the voltage value at the midpoint of the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; wherein, the detection component outputs a first level signal and a second level signal according to the comparison result of the first comparison electrical signal and the second comparison electrical signal, and the first level signal and the second level signal constitute the square wave signal.

[0013] Further, the detection module includes an output circuit for outputting the first level signal and the second level signal, and a third step-down resistor R11 is arranged on the output circuit.

[0014] Further, the detection module includes: a sampling capacitor C3, the sampling capacitor C3 is arranged on the first comparison circuit, and the sampling capacitor C3 is located between the first comparison circuit and the sampling module.

[0015] Further, the detection module includes: a first step-down resistor R6, the first step-down resistor R6 is arranged on the first comparison circuit, and the first step-down resistor R6 is located between the sampling capacitor C3 and the sampling module; a step-down circuit, connected to the first comparison circuit, and a second step-down resistor R5 is arranged on the step-down circuit; the step-down circuit is circuit-connected between the first step-down resistor R6 and the sampling capacitor C3.

[0016] A frequency converter structure includes: a frequency converter; the detection device as described above; the detection device is electrically connected to the circuit of the frequency converter.

[0017] Beneficial effects:

[0018] The detection device includes a sampling module, the sampling module is electrically connected to the first phase of the circuit to be detected and the sampling module is electrically connected to the second phase of the circuit to be detected; the sampling module outputs a sampling electrical signal according to the electrical signals of the first phase and the second phase; a detection module, the detection module is connected to the sampling module to receive the sampling electrical signal, and the sampling module compares the sampling electrical signal to output a square wave signal according to the sampling electrical signal. With the above arrangement, the sampling module is used to connect to the circuit to be detected to collect and process the electrical signals of the first phase and the second phase. Then, the detection module compares the sampling electrical signal output by the sampling module, detects the frequency of the sampling electrical signal, and outputs the frequency in the form of a square wave signal, so as to resist external interference and solve the technical problem that the frequency of the frequency converter detected in the related art is inaccurate. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of the detection device adopted in the embodiment of the present invention.

[0020] Among them, the above drawings include the following reference numerals:

[0021] 101, the first phase; 102, the second phase;

[0022] 1, the sampling module; 11, the sampling component;

[0023] 2, the detection module; 21, the detection component. Detailed Embodiments

[0024] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0025] See Figure 1 , according to an embodiment of the present invention, a detection device is provided, including: a sampling module 1, the sampling module 1 is electrically connected to the first phase 101 of the circuit to be detected, and the sampling module 1 is electrically connected to the second phase 102 of the circuit to be detected; the sampling module 1 outputs a sampling electrical signal according to the electrical signals of the first phase 101 and the second phase 102; a detection module 2, the detection module 2 is connected to the sampling module 1 to receive the sampling electrical signal, and the sampling module 1 compares the sampling electrical signal to output a square wave signal according to the sampling electrical signal.

[0026] With the above settings, the sampling module 1 is connected to the circuit to be detected to collect and process the electrical signals of the first phase 101 and the second phase 102. Then, the detection module 2 compares the sampling electrical signal output by the sampling module 1, detects the frequency of the sampling electrical signal, and outputs the frequency in the form of a square wave signal, so as to resist external interference and solve the technical problem of inaccurate frequency detection of the inverter in the related art.

[0027] In the detection device of this embodiment, see Figure 1 , the sampling module 1 includes: a sampling component 11, the sampling component 11 is respectively connected to the first phase 101 and the second phase 102, and the sampling component 11 outputs a sampling electrical signal according to the voltage difference between the first phase 101 and the second phase 102. In this way, through the voltage difference between the first phase 101 and the second phase 102, the frequency of the circuit to be detected can be judged, so that the output sampling signal can reflect the frequency of the circuit to be detected, which is convenient for judgment.

[0028] See Figure 1 , in the detection device of this embodiment, the sampling module 1 includes: a first sampling circuit, one end of the first sampling circuit is connected to the first phase 101, and the other end of the first sampling circuit is connected to the sampling component 11; a first filter capacitor C2, the first filter capacitor C2 is connected in parallel with the first sampling circuit; a first filter resistor R4, the first filter resistor R4 is connected in parallel with the first filter capacitor C2. In this way, the first filter capacitor C2 and the first filter resistor R4 can be used to filter the collected signal, so that the signal resists interference.

[0029] In the detection device of this embodiment, seeFigure 1 , the sampling module 1 includes: a second sampling circuit, one end of the second sampling circuit is connected to the second phase 102, and the other end of the second sampling circuit is connected to the sampling component 11; a second filter capacitor C1, the second filter capacitor C1 is connected in parallel with the second sampling circuit; a second filter resistor R3, the second filter resistor R3 is connected in parallel with the second filter capacitor C1. In this way, the second filter capacitor C1 and the second filter resistor R3 can be used to filter the collected signal, so that the signal can resist interference.

[0030] See Figure 1 , in the detection device of this embodiment, a first proportional resistor R1 is provided on the first sampling circuit; a second proportional resistor R2 is provided on the second sampling circuit; the ratio of the resistance value of the first proportional resistor R1 to the resistance value of the first filter resistor R4 is equal to the ratio of the resistance value of the second proportional resistor R2 to the resistance value of the second filter resistor R3. In this way, the second filter capacitor C1 and the second filter resistor R3 can be used to filter the collected signal, so that the signal can resist interference.

[0031] Specifically, in the detection device of this embodiment, through the above settings, high-frequency interference waves with frequencies above can be filtered out, leaving waves with frequencies below .

[0032] In the detection device of this embodiment, see Figure 1 , the detection module 2 includes: a first comparison circuit, the first comparison circuit is connected to the sampling module 1 to receive the sampled electrical signal; the first comparison circuit outputs a first comparison electrical signal according to the sampled electrical signal; a detection component 21, the detection component 21 is connected to the first comparison circuit to receive the first comparison electrical signal; a second comparison circuit, the second comparison circuit is connected to the detection component 21 to output a second comparison electrical signal to the detection component 21; wherein, after comparing the first comparison electrical signal and the second comparison electrical signal, the detection component 21 outputs a square wave signal. Specifically, the function of the detection module 2 is to compare and amplify the sampled electrical signal and output an anti-interference frequency signal, so as to facilitate judgment.

[0033] See Figure 1, in the detection device of this embodiment, a first voltage-dividing resistor R7 and a second voltage-dividing resistor R8 are arranged on the first comparison circuit, and the detection component 21 is circuit-connected between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; the first comparison electrical signal is the voltage value at the midpoint of the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; a third voltage-dividing resistor R9 and a fourth voltage-dividing resistor R10 are arranged on the second comparison circuit, and the detection component 21 is circuit-connected between the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; the second comparison electrical signal is the voltage value at the midpoint of the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; wherein, the detection component 21 outputs a first level signal and a second level signal according to the comparison result of the first comparison electrical signal and the second comparison electrical signal, and the first level signal and the second level signal form a square wave signal. With the above settings, by comparing the voltage values, the frequency fluctuation is detected, and thus a square wave signal is formed, which can accurately reflect the frequency of the circuit to be detected.

[0034] See Figure 1 , in the detection device of this embodiment, the detection module 2 includes an output circuit for outputting a first level signal and a second level signal, and a third step-down resistor R11 is arranged on the output circuit. In this way, after the signal output by the detection component 21 is limited by the resistor R11, the output signal is the output signal of a high anti-interference type frequency detection current.

[0035] See Figure 1 , in the detection device of this embodiment, the detection module 2 includes: a sampling capacitor C3, the sampling capacitor C3 is arranged on the first comparison circuit, and the sampling capacitor C3 is located between the first comparison circuit and the sampling module 1. Specifically, by using the charging and discharging function of the sampling capacitor C3, the voltage signal with positive and negative transformation output by the sampling module 1 is transmitted to the detection module 2 for the detection module 2 to make a comparison.

[0036] In the detection device of this embodiment, see Figure 1 , the detection module 2 includes: a first step-down resistor R6, the first step-down resistor R6 is arranged on the first comparison circuit, and the first step-down resistor R6 is located between the sampling capacitor C3 and the sampling module 1; a step-down circuit, connected to the first comparison circuit, and a second step-down resistor R5 is arranged on the step-down circuit; the step-down circuit is circuit-connected between the first step-down resistor R6 and the sampling capacitor C3. In this way, the sampling signal output by the sampling module 1 is step-down processed for the detection module 2 to make a comparison.

[0037] The structure of the frequency converter in this embodiment includes: a frequency converter; the detection device as described above; the detection device is electrically connected to the circuit of the frequency converter. The frequency converter structure in this embodiment adopts a highly anti-interference detection device, which can accurately calculate the power supply frequency of the photovoltaic centrifuge, achieving a more stable and accurate frequency protection function and frequency adaptability function. It solves the problem that the system will not wrongly perform grid-side frequency anomaly protection in high-interference application scenarios. Furthermore, it solves the problem of air conditioner shutdown caused thereby, thus bringing economic losses such as factory production line shutdown, project delay, workpiece damage, and forced closure of venues and warehouses.

[0038] See Figure 1 , the sampling module 1 uses the sampling component 11 (IC chip, IC_OP4228) to achieve the function of voltage differential sampling. The voltage UB of phase B (i.e., the first phase 101) and the voltage UC of phase C (i.e., the second phase 102) after voltage division and step-down processing are input into the sampling module 1. Among them, R1, R2, R3, and R4 are proportional resistors, which need to be used in combination and configured according to the ratio of R1:R4 = R2:R3. The reduction ratio of the sampling module 1 is R4 / R1. C1 is used in combination with R3, and C2 is used in combination with R4 to play a filtering role and perform the first-step filtering process on the grid voltage signal doped with interference. The output end of the sampling component 11 is the UCB signal after proportional reduction.

[0039] The UCB signal is subjected to voltage division and step-down processing by R6 and R5. The signal voltage UR6 at the output end of R6 = R5 / (R5 + R6). Among them, the setting rule is to ensure that the signal peak value at the output end of R6 is less than 3.3V. The signal at the output end of R6 is connected to the midpoint of R7 and R8 through C3. At this time, the midpoint voltage of R7 and R8 will fluctuate between 0 and 3.3V. The midpoint of R7 and R8 is connected to the same-named end of the detection component 21. The detection component 21 (IC chip, IC_LM293) is used to compare the signal passing through the midpoint of R7 and R8 with the midpoint voltage value of R12 and R9. Among them, the point voltage is the voltage division value of R12 and R9. Set R12 = R9, then the midpoint voltage is 1.65V. If the midpoint signal voltage value of R7 and R8 is greater than the midpoint signal voltage value of R12 and R9, the output end of the detection component 21 is pulled high to 3.3V through R10, and the detection component 21 outputs a high level; if the midpoint signal of R7 and R8 is less than the midpoint signal of R12 and R9, the detection component 21 outputs a low level. The output signal of the detection component 21 is output as the output signal AD_F of the high anti-interference frequency detection current after the current limiting effect of the resistor R11. The AD_F signal is a square wave signal with a frequency equal to the UCB frequency. The signal AD_F is input to the ECAP function pin of the main chip DSP chip. The ECAP function pin will detect the rising edge of the AD_F signal and calculate the frequency of the AD_F signal, thereby detecting the frequency of the grid line voltage UCB.

[0040] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0041] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and will not be elaborated here.

[0042] The serial numbers of the above embodiments of this application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0043] In the above embodiments of this application, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0044] The above are only the preferred embodiments of this application. It should be noted that for those of ordinary skill in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A detection device, characterized in that: include: A sampling module (1), the sampling module (1) being electrically connected to a first phase (101) of a circuit to be detected, and the sampling module (1) being electrically connected to a second phase (102) of the circuit to be detected; the sampling module (1) outputting a sampled electrical signal according to the electrical signals of the first phase (101) and the second phase (102); A detection module (2), the detection module (2) is connected to the sampling module (1) to receive the sampled electrical signal, and the sampling module (1) compares the sampled electrical signal to output a square wave signal according to the sampled electrical signal.

2. The detection device according to claim 1, characterized in that: The sampling module (1) comprises: A sampling component (11), the sampling component (11) is connected to the first phase (101) and the second phase (102) respectively, and the sampling component (11) outputs the sampled electrical signal according to the difference between the voltages on the first phase (101) and the second phase (102).

3. The detection device according to claim 2, characterized in that: The sampling module (1) comprises: a first sampling circuit, one end of the first sampling circuit being connected to the first phase (101), and the other end of the first sampling circuit being connected to the sampling component (11); A first filter capacitor C2, wherein the first filter capacitor C2 is connected in parallel with the first sampling circuit; A first filter resistor R4 is connected in parallel with the first filter capacitor C2.

4. The detection device according to claim 3, characterized in that: The sampling module (1) comprises: a second sampling circuit, one end of the second sampling circuit being connected to the second phase (102), and the other end of the second sampling circuit being connected to the sampling component (11); A second filter capacitor C1, wherein the second filter capacitor C1 is connected in parallel with the second sampling circuit; A second filter resistor R3 is connected in parallel with the second filter capacitor C1.

5. The detection device according to claim 4, characterized in that: The first sampling circuit is provided with a first proportional resistor R1; the second sampling circuit is provided with a second proportional resistor R2; the ratio of the resistance value of the first proportional resistor R1 to the resistance value of the first filter resistor R4 is equal to the resistance value of the second proportional resistor R2 to the resistance value of the second filter resistor R3.

6. The detection device according to claim 1, characterized in that: The detection module (2) comprises: A first comparison circuit, the first comparison circuit is connected to the sampling module (1) to receive the sampled electrical signal; the first comparison circuit outputs a first comparison electrical signal according to the sampled electrical signal; A detection component (21), the detection component (21) being connected to the first comparison circuit to receive the first comparison electrical signal; a second comparison circuit, the second comparison circuit being connected to the detection component (21) to output a second comparison electrical signal to the detection component (21); Wherein, the detection component (21) outputs the square wave signal after comparing the first comparison electrical signal and the second comparison electrical signal.

7. The detection device according to claim 6, characterized in that: The first comparison circuit is provided with a first voltage-dividing resistor R7 and a second voltage-dividing resistor R8, the detection component (21) is connected to the circuit between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; the first comparison electrical signal is the voltage value of the midpoint between the first voltage-dividing resistor R7 and the second voltage-dividing resistor R8; The second comparison circuit is provided with a third voltage-dividing resistor R9 and a fourth voltage-dividing resistor R10, and the detection component (21) is connected to the circuit between the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; the second comparison electrical signal is the voltage value of the midpoint between the third voltage-dividing resistor R9 and the fourth voltage-dividing resistor R10; The detection component (21) outputs a first level signal and a second level signal according to a comparison result of the first comparison electrical signal and the second comparison electrical signal, and the first level signal and the second level signal constitute the square wave signal.

8. The detection device according to claim 7, characterized in that: The detection module (2) comprises an output circuit for outputting the first level signal and the second level signal, and a third voltage-dropping resistor R11 is provided on the output circuit.

9. The detection device according to claim 6, characterized in that: The detection module (2) comprises: A sampling capacitor C3, the sampling capacitor C3 is arranged on the first comparison circuit, and the sampling capacitor C3 is located between the first comparison circuit and the sampling module (1).

10. The detection device according to claim 9, characterized in that: The detection module (2) comprises: A first voltage-dropping resistor R6, wherein the first voltage-dropping resistor R6 is arranged on the first comparison circuit, and the first voltage-dropping resistor R6 is located between the sampling capacitor C3 and the sampling module (1); A step-down circuit is connected to the first comparison circuit, and a second step-down resistor R5 is provided on the step-down circuit; the step-down circuit is connected to the circuit between the first step-down resistor R6 and the sampling capacitor C3.

11. A frequency converter structure, characterized in that: include: Frequency converter; The detection device according to any one of claims 1 to 10; The detection device is electrically connected to the circuit of the frequency converter.

Images