Signal detection circuit of photovoltaic inverter and water heating device

Abstract

The utility model relates to hot water supply equipment, and discloses a signal detection circuit of a photovoltaic inverter and a hot water device, and the signal detection circuit comprises a control module which is provided with a detection port; the signal output module is provided with a first branch circuit and a second branch circuit, and the first branch circuit and the second branch circuit are both connected with the detection port; the signal output module is used for outputting a detection signal; the first branch circuit is provided with a contact interface unit which is used for being connected with a contact signal circuit. The second branch is provided with an isolation rectification unit, and the isolation rectification unit is used for accessing an AC signal circuit or a DC signal circuit. According to the utility model, different types of signal detection share one detection port, detection signals are uniformly output through the signal output module, and the detection port receives corresponding detection signals by correspondingly controlling the on-off of the first branch circuit or the second branch circuit, so that the reception of signal instructions of the photovoltaic inverter is realized; a plurality of signal detection circuits do not need to be arranged, so that the circuit structure is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of hot water supply equipment, in particular to a signal detection circuit of a photovoltaic inverter and a hot water device. Background Art

[0002] In a heat pump hot water device configured with solar energy, the heat pump water heater usually needs to receive signal instructions from a photovoltaic inverter. Different photovoltaic inverters will output different types of signal instructions. According to the corresponding signal types, the output circuits of the photovoltaic inverter can be divided into a contact signal circuit, an AC signal circuit, and a DC signal circuit. At present, in a heat pump water heater, the signal detection circuit for detecting the signal output by the photovoltaic inverter usually can only detect a single type of signal, which results in that the heat pump water heater cannot match all types of photovoltaic inverters, limiting the application range of the heat pump water heater. If multiple types of photovoltaic inverters are to be adapted, multiple signal detection circuits need to be set in the heat pump water heater to detect different types of signals respectively, resulting in complex circuit design and low circuit utilization rate. Summary of the Utility Model

[0003] The first technical problem solved by the utility model is to provide a signal detection circuit of a photovoltaic inverter, which effectively solves the problem of complex circuit design that multiple signal detection circuits need to be set to detect different types of signals of the photovoltaic inverter at present.

[0004] The second technical problem solved by the utility model is to provide a hot water device, which effectively solves the problem of complex circuit design that multiple signal detection circuits need to be set to detect different types of signals of the photovoltaic inverter at present.

[0005] The above first technical problem is solved by the following technical solutions:

[0006] A signal detection circuit of a photovoltaic inverter includes:

[0007] A control module with a detection port;

[0008] A signal output module with a first branch and a second branch. Both the first branch and the second branch are connected to the detection port. The signal output module is used to output a detection signal;

[0009] The first branch is provided with a contact interface unit, which is used to access a contact signal circuit, and the contact signal circuit is used to control the on-off of the first branch;

[0010] The second branch is provided with an isolation rectification unit, which is used to access an AC signal circuit or a DC signal circuit, and the AC signal circuit or the DC signal circuit is used to control the on-off of the second branch through the isolation rectification unit.

[0011] Compared with the background art, the signal detection circuit of the photovoltaic inverter described in the present utility model has the following beneficial effects: The signal output module has a first branch and a second branch. A contact interface unit is provided on the first branch to access the contact signal circuit, and an isolation rectification unit is provided on the second branch to access the AC signal circuit or the DC signal circuit. Thus, the signal output module can access the signal circuits of different types of photovoltaic inverters. Moreover, both the first branch and the second branch are connected to the detection port. Different types of signal detections share one detection port. The detection signals are uniformly output through the signal output module, and by correspondingly controlling the on / off of the first branch or the second branch, the detection port receives the corresponding detection signals, realizing the reception of the signal commands of the photovoltaic inverter. There is no need to set up multiple signal detection circuits, thereby simplifying the circuit structure.

[0012] In one embodiment, the isolation rectification unit includes an optocoupler U1. The input end of the optocoupler U1 is connected to the AC signal circuit or the DC signal circuit, and the output end of the optocoupler U1 is connected to the second branch.

[0013] In one embodiment, the model of the optocoupler U1 is PC817C.

[0014] In one embodiment, the isolation rectification unit further includes a resistor R3 and a diode D1. One end of the resistor R3 is connected to pin 1 of the input end of the optocoupler U1, and the other end of the resistor R3 is connected to the AC signal circuit or the DC signal circuit; the anode of the diode D1 is connected to pin 2 of the input end of the optocoupler U1, and the cathode of the diode D1 is connected to pin 1 of the input end of the optocoupler U1 and the resistor R3.

[0015] In one embodiment, the isolation rectification unit further includes a first terminal and a second terminal; the first terminal is connected to the resistor R3, and the second terminal is connected to the anode of the diode D1 and pin 2 of the input end of the optocoupler U1.

[0016] In one embodiment, the signal output module includes a resistor R1. One end of the resistor R1 is connected to the power supply, and the other end of the resistor R1 is respectively connected to the detection port, one end of the first branch, and one end of the second branch; the other end of the first branch is grounded; the other end of the second branch is grounded.

[0017] In one embodiment, the signal output module further includes a resistor R2 and a capacitor C1. One end of the resistor R2 is connected to the detection port, and the other end of the resistor R2 is respectively connected to the resistor R1, the first branch, and the second branch; one side of the capacitor C1 is connected to the detection port and the resistor R2, and the other side of the capacitor C1 is grounded.

[0018] In one embodiment, the contact interface unit includes a third terminal and a fourth terminal. The third terminal is connected to the resistor R1 and the detection port; the fourth terminal is grounded.

[0019] In one of the embodiments, the control module uses a single-chip microcomputer.

[0020] The above second technical problem is solved by the following technical solution:

[0021] A hot water device includes a heat pump device, a photovoltaic inverter, and a signal detection circuit of the photovoltaic inverter as described in any one of the above. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a circuit schematic diagram of a signal detection circuit of a photovoltaic inverter according to an embodiment of the present invention;

[0024] Figure 2 It is a circuit schematic diagram of the control module in a signal detection circuit of a photovoltaic inverter according to an embodiment of the present invention;

[0025] Figure 3 It is a structural schematic diagram of a heat pump water heater according to an embodiment of the present invention.

[0026] Description of the reference numerals:

[0027] 1. Control module; 2. Signal output module; 3. Contact interface unit; 4. Isolation rectification unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0029] In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0030] As described in the background art, the signal detection circuit for detecting the signals output by a photovoltaic inverter can generally only detect a single type of signal. If a hot water device is to be adapted to multiple types of photovoltaic inverters, multiple signal detection circuits need to be provided to detect different types of signals respectively, resulting in complex circuit design and low circuit utilization rate.

[0031] Based on this, the present utility model provides a signal detection circuit for a photovoltaic inverter and a hot water device, which can realize the multiplexing of detection circuits and detection ports for different types of signals and simplify the circuit structure.

[0032] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 3 ,

[0033] According to an embodiment of the present utility model, on the one hand, a signal detection circuit for a photovoltaic inverter is provided. Figure 1 FIG. is a circuit schematic diagram of a signal detection circuit for a photovoltaic inverter according to an embodiment of the present utility model. As Figure 1 shown, the signal detection circuit includes a control module 1 and a signal output module 2. Among them, the control module 1 has a detection port for outputting the result of whether a signal from a photovoltaic inverter is received to the hot water device. The control module 1 can be the main control board of the hot water device. The signal output module 2 is used for outputting a detection signal; the signal output module 2 has a first branch and a second branch, and both the first branch and the second branch are connected to the detection port.

[0034] In this embodiment, as Figure 1 shown, the first branch is provided with a contact interface unit 3, and the contact interface unit 3 is used for accessing a contact signal circuit, and the contact signal circuit is used for controlling the on / off of the first branch; the first branch is used for accessing and detecting the output signal of a photovoltaic inverter with a contact signal type. The second branch is provided with an isolation rectification unit 4, and the isolation rectification unit 4 is used for accessing an AC signal circuit or a DC signal circuit, and the AC signal circuit or the DC signal circuit is used for controlling the on / off of the second branch through the isolation rectification unit 4; the second branch is used for accessing and detecting the output signal of a photovoltaic inverter with an AC voltage signal or a DC signal type.

[0035] In this embodiment, as Figure 1As shown, when the contact signal circuit connected to the contact interface unit 3 outputs a contact signal, the first branch is connected, and a closed loop is formed between the contact interface unit 3 and the signal output module 2 on the first branch. At this time, the second branch is in a short - circuit state. The signal output module 2 detects the signal of the contact type input on the first branch and outputs a detection signal. When the AC signal circuit connected to the isolation rectification unit 4 outputs an AC voltage signal, or the DC signal circuit connected to it outputs a DC voltage signal, the second branch is connected, and a closed loop is formed between the isolation rectification unit 4 and the signal output module 2 on the second branch. At this time, the first branch is in a short - circuit state. The signal output module 2 detects the AC or DC type signal input on the second branch and outputs a detection signal. Thus, different types of signal detections share one detection port, and the detection signals are uniformly output through the signal output module 2, eliminating the need to set up multiple signal detection circuits, thereby simplifying the circuit structure and reducing costs.

[0036] In one embodiment, as Figure 1 shown, the isolation rectification unit 4 includes an optocoupler U1, that is, an optocoupler device is used as the isolation device. Among them, the input end of the optocoupler U1 is connected to the AC signal circuit or the DC signal circuit, and the output end of the optocoupler U1 is connected to the second branch. The voltage signal input from the AC signal circuit or the DC signal circuit is isolated from the signal output module 2 through the optocoupler U1, thereby improving the safety and reliability of the signal detection circuit. In other embodiments, the isolation rectification unit 4 can also adopt a combination of a relay and a rectifier bridge.

[0037] In one embodiment, when the isolation rectification unit 4 is connected to the DC signal circuit, the DC signal circuit inputs a DC voltage signal. The light - emitting diode in the optocoupler U1 is excited by the DC voltage signal to generate a light signal, and the photosensitive triode in the optocoupler U1 is turned on by the light signal, thus connecting the second branch.

[0038] In one embodiment, when the isolation rectification unit 4 is connected to the AC signal circuit, the AC signal circuit inputs an AC voltage signal. In the positive half - cycle of the AC voltage signal, the light - emitting diode in the optocoupler U1 is excited by the DC voltage signal to generate a light signal, and the photosensitive triode in the optocoupler U1 is turned on by the light signal, thus connecting the second branch. In the negative half - cycle of the AC voltage signal, the conduction direction of the light - emitting diode in the optocoupler U1 is opposite to the direction of the AC voltage signal. At this time, the light - emitting diode is not excited, the photosensitive triode in the optocoupler U1 is not turned on, and the second branch is disconnected.

[0039] In one embodiment, the model of the optocoupler U1 can be PC817C. It should be noted that the model of the optocoupler U1 here is only an example. In actual applications, other models of optocoupler devices can be used according to circuit requirements, and no specific restrictions are made here.

[0040] In one embodiment, pin 1 of the input terminal of optocoupler U1 corresponds to the anode of the light-emitting diode inside optocoupler U1, and pin 2 of the input terminal of optocoupler U1 corresponds to the cathode of the light-emitting diode inside optocoupler U1. Pin 3 of the output terminal of optocoupler U1 corresponds to the emitter of the phototransistor inside optocoupler U1, and pin 4 of the output terminal of optocoupler U1 corresponds to the collector of the phototransistor inside optocoupler U1.

[0041] In one embodiment, as Figure 1 shown, the isolation rectification unit 4 further includes a resistor R3 and a diode D1. One end of the resistor R3 is connected to pin 1 of the input terminal of optocoupler U1, and the other end of the resistor R3 is connected to an AC signal circuit or a DC signal circuit. Since the voltage and current that the light-emitting diode in optocoupler U1 can withstand are relatively small, if the AC signal current or the DC signal circuit is directly connected to the input terminal of optocoupler U1, it may cause the light-emitting diode of optocoupler U1 to be broken down. Therefore, the resistor R3 is connected in series between optocoupler U1 and the AC signal circuit or the DC signal circuit. The resistor R3 steps down and limits the current of the electrical signal input by the AC signal circuit or the DC signal circuit, especially the AC voltage signal input by the AC signal circuit, to protect optocoupler U1. The anode of the diode D1 is connected to pin 2 of the input terminal of optocoupler U1, and the cathode of the diode D1 is connected to pin 1 of the input terminal of optocoupler U1 and the resistor R3; that is to say, the diode D1 is connected between the two input pins of optocoupler U1, and it is in parallel with the photosensitive diode inside optocoupler U1. The anode of the diode D1 is connected to the cathode of the photosensitive diode, and the cathode of the diode D1 is connected to the anode of the photosensitive diode. When the AC voltage signal is in the negative half-cycle signal, the diode D1 conducts, thereby protecting the photosensitive diode inside optocoupler U1 from being broken down and damaged.

[0042] In one embodiment, as Figure 1 shown, the isolation rectification unit 4 further includes a first terminal and a second terminal. The first terminal is terminal 1 of the signal input port CN2 and serves as the positive input terminal of the AC signal circuit or the DC signal circuit, and is connected to the resistor R3; the second terminal is terminal 2 of the signal input port CN2 and serves as the negative input terminal of the AC signal circuit or the DC signal circuit, and is connected to the anode of the diode D1 and pin 2 of the input terminal of optocoupler U1.

[0043] In one embodiment, as Figure 1As shown, the signal output module 2 includes a resistor R1. One end of the resistor R1 is connected to a power supply, and the other end of the resistor R1 is respectively connected to a detection port, one end of a first branch, and one end of a second branch; at the same time, the other ends of the first branch and the second branch are both grounded. Optionally, the power supply connected to the resistor R1 is a +5V power supply. The resistor R1 serves as a pull-up resistor, pulling the detection signal I_PVS at the detection port to a high level when the first branch and the second branch are disconnected, and pulling the detection signal I_PVS at the detection port to a low level when the first branch or the second branch is conducting. Thus, according to the high and low levels of the detection signal I_PVS at the detection port, it is possible to confirm whether the photovoltaic inverter has a signal output.

[0044] In one embodiment, when accessing an AC signal circuit, since the AC voltage signal input by the AC signal circuit has positive and negative half-cycle signals, when the positive half-cycle signal is input, the second branch is connected, and at this time, the detection signal I_PVS at the detection port is a low-level signal; when the negative half-cycle signal is input, the second branch is disconnected, and there is no electrical signal output from the second branch. At this time, the detection signal I_PVS at the detection port is a high-level signal. When accessing a DC signal circuit, the DC voltage signal input by the DC signal circuit will keep the second branch in a connected state all the time, and the detection signal I_PVS at the detection port is always a low-level signal.

[0045] If accessing a contact signal circuit, when there is a contact signal, the first branch is connected, and at this time, the detection signal I_PVS at the detection port is a low-level signal; when there is no contact signal, the first branch is disconnected, and at this time, the detection signal I_PVS at the detection port is a high-level signal. It can be understood that when a low-level signal appears at the detection port, it is determined that the photovoltaic inverter has a signal input.

[0046] In one embodiment, as Figure 1 shown, the contact interface unit 3 includes a signal input port CN1. The signal input port CN1 includes a third terminal and a fourth terminal. Among them, the third terminal is the 1st terminal of the signal input port CN1 and is connected to the resistor R1 and the detection port; the fourth terminal is the 2nd terminal of the signal input port CN1, and the fourth terminal is grounded.

[0047] In one embodiment, the signal output module 2 further includes a resistor R2 and a capacitor C1. Among them, one end of the resistor R2 is connected to the detection port, and the other end of the resistor R2 is respectively connected to the resistor R1, the first branch, and the second branch; one side of the capacitor C1 is connected to the detection port and the resistor R2, and the other side of the capacitor C1 is grounded. The resistor R2 and the capacitor C1 are used to perform anti-interference filtering processing on the detection signal I_PVS to improve the reliability of the detection signal output by the signal output module 2.

[0048] In one embodiment, Figure 2It is a schematic circuit diagram of a control module in a signal detection circuit of a photovoltaic inverter according to an embodiment of the present invention. As Figure 2 shown, the control module 1 can use a single-chip microcomputer. The detection signal I_PVS of the signal output module 2 is input into the detection port of the control module 1. The single-chip microcomputer determines whether the photovoltaic inverter has a signal output according to the detection signal I_PVS. Specifically, if the detection signal I_PVS is at a high level, the single-chip microcomputer determines that the photovoltaic inverter has no signal output. If the detection signal I_PVS is at a low level, the single-chip microcomputer determines that the photovoltaic inverter has a signal output.

[0049] In an embodiment, the model of the single-chip microcomputer can be CMS80F2313. It should be noted that the model of the single-chip microcomputer here is only an example. In actual applications, other models of single-chip microcomputers can be used according to the circuit requirements, and no specific restrictions are made here.

[0050] According to an embodiment of the present invention, on the other hand, a hot water device is provided. Figure 3 It is a schematic structural diagram of a hot water device according to an embodiment of the present invention. As Figure 3 shown, the hot water device includes a heat pump device, a photovoltaic inverter, and a signal detection circuit of the photovoltaic inverter as described in any of the above embodiments.

[0051] In the specific content of the above specific implementation manner, each technical feature can be combined arbitrarily without contradiction. For the sake of concise description, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features does not exist in contradiction, it should be considered to be within the scope described in this specification.

[0052] The specific content of the above specific implementation manner only expresses several implementation manners of the present invention. Its description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A signal detection circuit for a photovoltaic inverter, characterized in that, Comprising: A control module (1) having a detection port; A signal output module (2) having a first branch and a second branch, both the first branch and the second branch being connected to the detection port; the signal output module (2) is used for outputting a detection signal; The first branch is provided with a contact interface unit (3), and the contact interface unit (3) is used for accessing a contact signal circuit, and the contact signal circuit is used for controlling the on / off of the first branch; The second branch is provided with an isolation rectification unit (4), and the isolation rectification unit (4) is used for accessing an AC signal circuit or a DC signal circuit, and the AC signal circuit or the DC signal circuit is used for controlling the on / off of the second branch through the isolation rectification unit (4).

2. The signal detection circuit according to claim 1, characterized in that The isolation rectification unit (4) includes an optocoupler U1, an input end of the optocoupler U1 is connected to the AC signal circuit or the DC signal circuit, and an output end of the optocoupler U1 is connected to the second branch.

3. The signal detection circuit according to claim 2, characterized in that, The model of the optocoupler U1 is PC817C.

4. The signal detection circuit according to claim 2, wherein, The isolation rectification unit (4) further includes a resistor R3 and a diode D1. One end of the resistor R3 is connected to pin 1 of the input end of the optocoupler U1, and the other end of the resistor R3 is connected to the AC signal circuit or the DC signal circuit; an anode of the diode D1 is connected to pin 2 of the input end of the optocoupler U1, and a cathode of the diode D1 is connected to pin 1 of the input end of the optocoupler U1 and the resistor R3.

5. The signal detection circuit according to claim 4, characterized in that The isolation rectification unit (4) further includes a first terminal and a second terminal; the first terminal is connected to the resistor R3, and the second terminal is connected to the anode of the diode D1 and pin 2 of the input end of the optocoupler U1.

6. The signal detection circuit according to claim 1, wherein The signal output module (2) includes a resistor R1. One end of the resistor R1 is connected to a power supply, and the other end of the resistor R1 is respectively connected to the detection port, one end of the first branch and one end of the second branch; the other end of the first branch is grounded; the other end of the second branch is grounded.

7. The signal detection circuit according to claim 6, wherein The signal output module (2) further includes a resistor R2 and a capacitor C1. One end of the resistor R2 is connected to the detection port, and the other end of the resistor R2 is respectively connected to the resistor R1, the first branch and the second branch; a primary side of the capacitor C1 is connected to the detection port and the resistor R2, and a secondary side of the capacitor C1 is grounded.

8. The signal detection circuit according to claim 6, characterized in that, The contact interface unit (3) includes a third terminal and a fourth terminal, the third terminal is connected to the resistor R1 and the detection port; the fourth terminal is grounded.

9. The signal detection circuit according to claim 1, wherein The control module (1) uses a single-chip microcomputer.

10. A hot water device, characterized in that, Including a heat pump device, a photovoltaic inverter, and a signal detection circuit of the photovoltaic inverter according to any one of claims 1-9.

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