CN106997008B - Insulation detection device and inverter - Google Patents
Insulation detection device and inverter Download PDFInfo
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- CN106997008B CN106997008B CN201710398983.2A CN201710398983A CN106997008B CN 106997008 B CN106997008 B CN 106997008B CN 201710398983 A CN201710398983 A CN 201710398983A CN 106997008 B CN106997008 B CN 106997008B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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Abstract
The invention provides an insulation detection device and an inverter, wherein a control signal is output to a control end of a boost conversion circuit to control the boost conversion circuit to work, so that the voltage of a direct current bus is increased, and the insulation impedance of a photovoltaic array in a photovoltaic power generation system is calculated according to the detection voltage after the voltage of the direct current bus is increased to an expected voltage; the insulation detection device is connected between the positive electrode and the negative electrode of the direct current bus and the ground, and the detection voltage of the insulation detection device changes in proportion to the voltage of the direct current bus; when the DC bus voltage rises, the detection voltage for calculation rises in equal proportion. Therefore, even if the insulation impedance of the negative electrode of the photovoltaic array is small or the voltage between the positive electrode and the negative electrode of the photovoltaic array is small, the insulation impedance of the photovoltaic array can be calculated according to the increased detection voltage, and the problem of large insulation detection error in the prior art is solved.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to an insulation detection device and an inverter.
Background
In the process of photovoltaic grid-connected power generation, if the resistance value of the ground insulation resistor of the photovoltaic array is lower than a certain index requirement or the insulation resistor fails, the personal safety of photovoltaic power generation equipment or a user can be endangered. Therefore, the insulation resistance of the photovoltaic array needs to be detected before the photovoltaic array is connected to the grid.
The prior art generally uses an unbalanced bridge approach as shown in fig. 1, where Vpv is the voltage between the positive PV + and negative PV-poles of the PV array and Viso is the voltage between the ground point PE and the negative PV-pole of the PV array. A relational expression of the sizes of Viso and Vpv can be obtained through voltage division of resistors (R +, R-, R1 and R2), and two relational expressions before and after disturbance of the simultaneous switch K1 can be obtained through solving the resistance R + of PV + to PE and the resistance R-of PV-to PE.
However, when R-is small or Vpv is small, since Vpv and R1 are not changed, Viso has little voltage difference before and after disturbance of the switch K1, or Viso is small before and after disturbance, and the detected error is large, which may cause the inverter to be under-protected or not protected.
Disclosure of Invention
The invention provides an insulation detection device and an inverter, which aim to solve the problem of large detection error in the prior art.
In order to achieve the purpose, the technical scheme provided by the application is as follows:
an insulation detection device is arranged between an inverter circuit and at least one boost conversion circuit of a photovoltaic power generation system; the port of the insulation detection device comprises: a first end, a second end, a third end and a fourth end; wherein:
the first end is connected with the positive electrode of the direct current bus;
the second end is connected with the negative electrode of the direct current bus;
the third end is grounded;
the fourth end is connected with the control end of the boost conversion circuit;
the insulation detection device is used for outputting a control signal to the control end of the boost conversion circuit to control the boost conversion circuit to work, so that the voltage of the direct-current bus is increased, and the insulation impedance of the photovoltaic array in the photovoltaic power generation system is obtained through calculation according to the detection voltage after the voltage of the direct-current bus is increased to an expected voltage.
Preferably, the insulation detecting device includes: the voltage detection circuit comprises a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the first resistor is arranged between the first end and the third end;
the second resistor is arranged between the second end and the third end;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the processor is used for outputting the control signal to control the boost conversion circuit to work so as to increase the voltage of the direct current bus, and after the voltage of the direct current bus is increased to an expected voltage, the insulation impedance of the photovoltaic array in the photovoltaic power generation system is calculated according to the detection voltage output by the voltage detection circuit under different direct current bus voltages.
Preferably, the processor is further configured to: before the control signal is output, if the detected direct current bus voltage is equal to the maximum allowable input voltage of the inverter, calculating to obtain the insulation impedance of the photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under different direct current bus voltages after the detected direct current bus voltage is reduced.
Preferably, the insulation detecting device includes: the voltage detection circuit comprises a switch, a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the switch and the first resistor are arranged between the first end and the third end in series;
the second resistor is arranged between the second end and the third end;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the second output end of the processor is connected with the control end of the switch;
the processor is used for controlling the switch to be switched on or switched off and outputting the control signal so as to control the boost conversion circuit to work and enable the voltage of the direct-current bus to be increased; and after the voltage of the direct current bus is increased to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under the on and off of the switch.
Preferably, the insulation detecting device includes: the voltage detection circuit comprises a switch, a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the first resistor is arranged between the first end and the third end;
the switch and the second resistor are arranged between the second end and the third end in series;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the second output end of the processor is connected with the control end of the switch;
the processor is used for controlling the switch to be switched on or switched off and outputting the control signal so as to control the boost conversion circuit to work and enable the voltage of the direct-current bus to be increased; and after the voltage of the direct current bus is increased to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under the on and off of the switch.
Preferably, the processor is further configured to: before the control signal is output, if the detected voltage of the direct current bus is greater than or equal to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system directly according to the detection voltage output by the voltage detection circuit under the condition that the switch is turned on and off.
Preferably, the processor is integrated into a controller in the inverter; or the processor is a digital signal processor DSP based on a single chip microcomputer or an ARM processor.
Preferably, the voltage detection circuit is an analog-to-digital converter ADC.
An inverter, comprising: an inverter circuit and any one of the above insulation detection devices.
Preferably, the method further comprises the following steps: at least one boost converter circuit.
According to the insulation detection device provided by the invention, the control signal is output to the control end of the boost conversion circuit to control the boost conversion circuit to work, so that the voltage of the direct-current bus is increased, and the insulation impedance of a photovoltaic array in the photovoltaic power generation system is calculated according to the detection voltage after the voltage of the direct-current bus is increased to an expected voltage; the insulation detection device is connected between the positive electrode and the negative electrode of the direct current bus and the ground, and the detection voltage of the insulation detection device changes in proportion to the voltage of the direct current bus; when the DC bus voltage rises, the detection voltage for calculation rises in equal proportion. Therefore, even if the insulation impedance of the negative electrode of the photovoltaic array is small or the voltage between the positive electrode and the negative electrode of the photovoltaic array is small, the insulation impedance of the photovoltaic array can be calculated according to the increased detection voltage, and the problem of large insulation detection error in the prior art is solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is an equivalent circuit diagram of an insulation detecting apparatus provided in the prior art;
fig. 2 is a schematic structural diagram of an insulation detection apparatus according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 4 is an equivalent circuit diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 5 is a schematic structural diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 6 is an equivalent circuit diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 7 is a schematic structural diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 8 is an equivalent circuit diagram of an insulation detecting apparatus according to another embodiment of the present invention;
fig. 9 is a schematic structural diagram of an insulation detecting apparatus according to another embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The invention provides an insulation detection device, which aims to solve the problem of large detection error in the prior art.
Referring to fig. 2, the insulation detection device is disposed between an inverter circuit and at least one boost converter circuit of a photovoltaic power generation system; the output end of the boost conversion circuit is connected with the direct current side of the inverter circuit, and the voltage at the connecting point is the direct current bus voltage; the inverter of the photovoltaic power generation system can be a three-phase inverter or a single-phase inverter; when the inverter is a group string inverter, the boost conversion circuit, the inverter circuit and the controller thereof are all arranged in the inverter; alternatively, the boost converter circuit may be disposed outside the inverter, and is not particularly limited herein. The number of the boost converter circuits may be determined according to a specific application environment, and is not particularly limited herein.
Specifically, as shown in fig. 2, the port of the insulation detecting apparatus includes: a first end, a second end, a third end and a fourth end; wherein:
the first end is connected with a direct current BUS positive electrode BUS +;
the second end is connected with a DC BUS negative electrode BUS-;
the third end is grounded PE;
the fourth end is connected with the control end of the boost conversion circuit;
the insulation detection device is used for outputting a control signal to a control end of the boost conversion circuit to control the boost conversion circuit to work, so that the voltage of the direct-current bus is increased to an expected voltage Vp, and the insulation impedance of the photovoltaic array in the photovoltaic power generation system is calculated according to the detection voltage after the voltage of the direct-current bus is increased to the expected voltage Vp.
Preferably, the desired voltage Vp is equal to or less than the system maximum open circuit voltage, preferably the system maximum open circuit voltage.
The specific work of the insulation detection device is as follows:
before the inverter is connected to the grid, the boost conversion circuit is controlled to boost, and after the voltage of the direct-current bus is boosted, disturbance is implemented to obtain detection voltages before and after the disturbance; and then, calculating the insulation impedance of the photovoltaic array by using a simultaneous equation set according to the relationship between the two detection voltages and the internal circuit structure of the insulation detection device, namely the parallel value of the impedance R + of the photovoltaic array assembly PV + to the ground PE and the impedance R-of the photovoltaic array cathode PV-to-ground PE.
In the insulation detection device provided by the embodiment, since the insulation detection device is connected between the positive electrode and the negative electrode of the direct current bus and the ground, the detection voltage changes in proportion to the direct current bus voltage; when the dc bus voltage rises to the desired voltage Vp, the sensed voltage for calculation rises in equal proportion. Therefore, even if the insulation impedance of the negative electrode of the photovoltaic array is small or the voltage between the positive electrode and the negative electrode of the photovoltaic array is small, the insulation impedance of the photovoltaic array can be calculated according to the increased detection voltage, and the problem of large insulation detection error in the prior art is solved.
Another embodiment of the present invention further provides a specific insulation detecting apparatus, based on the above embodiment and fig. 2, as shown in fig. 3, the insulation detecting apparatus includes: a first resistor R1, a second resistor R2, a voltage detection circuit 101 and a processor 102; wherein:
the first resistor R1 is arranged between the first end and the third end, namely is respectively connected with the positive electrode BUS + of the direct current BUS and the ground PE;
the second resistor R2 is arranged between the second end and the third end, namely is respectively connected with the DC BUS negative electrode BUS-and the ground PE;
two input ends of the voltage detection circuit 101 are respectively connected with the second end and the third end, namely respectively connected with a DC BUS negative electrode BUS-and a ground PE;
the output end of the voltage detection circuit 101 is connected with the input end of the processor 102 and is used for outputting detection voltage for the processor 102 to calculate;
a first output end of the processor 102 is connected to a control end of the boost converting circuit, that is, a control end of the first switching tube Q1 in fig. 3, through a fourth end;
the processor 102 is configured to output a control signal to control the boost conversion circuit to operate, so as to increase the dc bus voltage, and calculate the insulation impedance of the photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit 101 under different dc bus voltages after the dc bus voltage is increased to an expected voltage.
The specific working principle is as follows:
referring to fig. 3, the inverter is powered on first, the positive electrode PV + of the photovoltaic array is powered on, and before the inverter is connected to the grid, the boost converter circuit is controlled by the processor 102 to boost the voltage to Vp1After the voltage at the two ends of the capacitor C1 is stabilized, the voltage detection circuit 101 detects that the lower bridge arm voltage is VISO1. Then, the boost circuit is controlled by the processor 102 to boost to Vp2Then the voltage detection circuit 101 detects the lower bridge arm voltage as VISO2。
Fig. 4 is an equivalent resistance circuit shown in fig. 3, which can be obtained according to the circuit theorem:
the joint formula (1) and the formula (2) can be solved to obtain the total insulation resistance R +// R of the positive electrode and the negative electrode of the photovoltaic array to the ground:
similarly, the two detection voltages output by the voltage detection circuit 101 can be calculated by the following equations (1) and (2):
from the formulas (4) and (5), when the DC bus voltage V is obtainedp1、Vp2When increasing, the detection voltage VISO1、VISO2The sampling rate is increased, the sampling precision is higher when the direct current bus voltage is larger, and therefore the problem that the detection error is large in the prior art is solved.
Particularly, when the actual voltage input by the photovoltaic array is equal to the maximum voltage of the system, the voltage is not boosted, the direct-current bus voltage at the moment is also the maximum allowable input voltage of the inverter, and the corresponding lower bridge arm voltage at the moment is VISO1(ii) a When the input voltage of the photovoltaic array changes, the voltage of the direct-current bus is lower than the maximum allowable input voltage of the inverter, and the voltage of the corresponding lower bridge arm is VISO2(ii) a And solving the total insulation resistance R +// R-of the positive electrode and the negative electrode of the photovoltaic array to the ground according to the formula (3), namely the insulation resistance of the photovoltaic array.
Alternatively, referring to fig. 5, the insulation detecting device includes: the voltage detection circuit comprises a switch K, a first resistor R1, a second resistor R2, a voltage detection circuit 101 and a processor 102; wherein:
the first resistor R1 is arranged between the first end and the third end, namely is respectively connected with the positive electrode BUS + of the direct current BUS and the ground PE;
the switch K and the second resistor R2 are connected in series between the second end and the third end, namely are respectively connected with the DC BUS negative electrode BUS-and the ground PE;
two input ends of the voltage detection circuit 101 are respectively connected with the second end and the third end, namely respectively connected with a DC BUS negative electrode BUS-and a ground PE;
the output end of the voltage detection circuit 101 is connected with the input end of the processor 102 and is used for outputting detection voltage for the processor 102 to calculate;
a first output end of the processor 102 is connected to a control end of the boost converting circuit, that is, a control end of the first switching tube Q1 in fig. 3, through a fourth end;
a second output end of the processor 102 is connected with a control end of the switch K;
the processor 102 is configured to control the switch K to be turned on or off, and output a control signal to control the boost converter circuit to operate, so as to increase the voltage of the dc bus; after the voltage of the direct current bus is increased to an expected voltage, the insulation impedance of the photovoltaic array in the photovoltaic power generation system is calculated according to the detection voltage output by the voltage detection circuit 101 when the switch K is turned on and off.
The specific working principle of the insulation detection device shown in fig. 5 is as follows:
firstly, the inverter is powered on, the positive electrode PV + of the photovoltaic array is powered on, and before the inverter is connected to the grid, the boost conversion circuit is controlled by the processor 102 to boost to a desired voltage VpAfter the voltage at the two ends of the capacitor C1 is stabilized, the processor 102 controls the switch K to be turned off, and the voltage detection circuit 101 detects that the voltage of the lower bridge arm is VISO1. Then, the processor 102 controls the switch K to be turned on, and the voltage detection circuit 101 detects that the lower bridge arm voltage is VISO2。
Fig. 6 is an equivalent resistance circuit shown in fig. 5, which can be obtained according to the circuit theorem:
the joint formula (6) and the formula (7) can be solved to obtain the total insulation resistance R +// R of the positive electrode and the negative electrode of the photovoltaic array to the ground:
similarly, the two detection voltages output by the voltage detection circuit 101 can be calculated by the following equations (6) and (7):
from the equations (9) and (10), when the DC bus voltage V is obtainedpWhen increasing, the detection voltage VISO1、VISO2Are all increased, the same sampling ratio is input into the processor 102, and the DC bus voltage VpThe larger the sampling precision is, the higher the sampling precision is, so that the problem of large detection error in the prior art is solved.
Still alternatively, referring to fig. 7, the insulation detecting apparatus includes: the voltage detection circuit comprises a switch K, a first resistor R1, a second resistor R2, a voltage detection circuit 101 and a processor 102; wherein:
the switch K and the first resistor R1 are arranged between the first end and the third end in series, namely are respectively connected with the positive electrode BUS + of the direct current BUS and the ground PE;
the second resistor R2 is arranged between the second end and the third end, namely is respectively connected with the DC BUS negative electrode BUS-and the ground PE;
two input ends of the voltage detection circuit 101 are respectively connected with the second end and the third end, namely respectively connected with a DC BUS negative electrode BUS-and a ground PE;
the output end of the voltage detection circuit 101 is connected with the input end of the processor 102 and is used for outputting detection voltage for the processor 102 to calculate;
a first output end of the processor 102 is connected to a control end of the boost converting circuit, that is, a control end of the first switching tube Q1 in fig. 3, through a fourth end;
a second output end of the processor 102 is connected with a control end of the switch K;
the processor 102 is configured to control the switch K to be turned on or off, and output a control signal to control the boost converter circuit to operate, so as to increase the voltage of the dc bus; after the voltage of the direct current bus is increased to an expected voltage, the insulation impedance of the photovoltaic array in the photovoltaic power generation system is calculated according to the detection voltage output by the voltage detection circuit 101 when the switch K is turned on and off.
Fig. 8 is an equivalent resistance circuit shown in fig. 7, which can be obtained according to the circuit theorem:
the joint formula (11) and the formula (12) can be solved to obtain the total insulation resistance R +// R of the positive electrode and the negative electrode of the photovoltaic array to the ground:
similarly, the two detection voltages output by the voltage detection circuit 101 can be calculated by the following equations (11) and (12):
from the equations (14) and (15), when the DC bus voltage V is obtainedpWhen increasing, the detection voltage VISO1、VISO2Are all increased, the same sampling ratio is input into the processor 102, and the DC bus voltage VpThe larger the sampling precision is, the higher the sampling precision is, so that the problem of large detection error in the prior art is solved.
Preferably, in the structure shown in fig. 5 or fig. 6, if the processor 102 detects that the dc bus voltage is equal to or higher than the desired voltage V before controlling the dc bus voltage to increasepThen, it indicates that the calculation accuracy at this time can meet the requirement, and the processor 102 may not perform the voltage boosting control but directly detect the voltage V under the on and off of the switch KISO1、VISO2And calculating to obtain the insulation impedance of the photovoltaic array in the photovoltaic power generation system.
It is worth noting that the desired voltage VpThe maximum allowable input voltage of the inverter may be equal to or lower than the maximum allowable input voltage of the inverter, and the calculation accuracy is satisfied.
Preferably, in the above embodiment, the processor 102 may be a controller integrated in the inverter; alternatively, the processor 102 may be a DSP (Digital Signal Processing) based on a single chip or an ARM processor.
Preferably, the voltage detection circuit 101 is an ADC (Analog-to-digital converter).
The voltage detection circuit 101 and the processor 102 may be determined according to the specific application environment, and are not limited herein and are within the scope of the present application.
Another embodiment of the present invention also provides an inverter including: inverter circuit and the insulation detection device in any one of the above embodiments.
In addition, at least one boost converter circuit may be integrated in the inverter to be applied to a distributed photovoltaic power generation system, and at this time, a connection schematic diagram of the insulation detection device is shown in fig. 9.
In different photovoltaic power generation systems, the inverter may be any inverter suitable for the current system, only the inside of the inverter includes the insulation detection device according to any of the above embodiments, and various other structures inside the inverter may be determined according to the specific application environment thereof, and are not described herein any more, and are all within the protection scope of the present application.
The rest of the working principle is the same as the above embodiment, and is not described in detail here.
The embodiments of the invention are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments can be referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (10)
1. An insulation detection device is characterized by being arranged between an inverter circuit and at least one boost conversion circuit of a photovoltaic power generation system; the input end of the boost conversion circuit is connected with the positive electrode and the negative electrode of the corresponding photovoltaic array; the port of the insulation detection device comprises: a first end, a second end, a third end and a fourth end; wherein:
the first end is connected with the positive electrode of the direct current bus;
the second end is connected with the negative electrode of the direct current bus;
the third end is grounded;
the fourth end is connected with the control end of the boost conversion circuit;
the insulation detection device is used for outputting a control signal to a control end of the boost conversion circuit when the insulation impedance of the negative electrode of the photovoltaic array or the voltage between the positive electrode and the negative electrode of the photovoltaic array is smaller than a corresponding preset value so as to control the boost conversion circuit to work, so that the voltage of the direct current bus is increased, and the insulation impedance of the photovoltaic array in the photovoltaic power generation system is obtained by calculation according to the detection voltage which is increased in equal proportion after the voltage of the direct current bus is increased to an expected voltage, so that the problem of large detection error caused by the fact that the insulation impedance of the negative electrode of the photovoltaic array or the voltage between the positive electrode and the negative electrode of the.
2. The insulation detection device according to claim 1, characterized in that the insulation detection device comprises: the voltage detection circuit comprises a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the first resistor is arranged between the first end and the third end;
the second resistor is arranged between the second end and the third end;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the processor is used for outputting the control signal to control the boost conversion circuit to work so as to increase the voltage of the direct current bus, and calculating the insulation impedance of the photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under different direct current bus voltages after the voltage of the direct current bus is increased to the expected voltage.
3. The insulation detection device of claim 2, wherein the processor is further configured to: before the control signal is output, if the detected direct current bus voltage is equal to the maximum allowable input voltage of the inverter, calculating to obtain the insulation impedance of the photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under different direct current bus voltages after the detected direct current bus voltage is reduced.
4. The insulation detection device according to claim 1, characterized in that the insulation detection device comprises: the voltage detection circuit comprises a switch, a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the switch and the first resistor are arranged between the first end and the third end in series;
the second resistor is arranged between the second end and the third end;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the second output end of the processor is connected with the control end of the switch;
the processor is used for controlling the switch to be switched on or switched off and outputting the control signal so as to control the boost conversion circuit to work and enable the voltage of the direct-current bus to be increased; and after the voltage of the direct current bus is increased to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under the on and off of the switch.
5. The insulation detection device according to claim 1, characterized in that the insulation detection device comprises: the voltage detection circuit comprises a switch, a first resistor, a second resistor, a voltage detection circuit and a processor; wherein:
the first resistor is arranged between the first end and the third end;
the switch and the second resistor are arranged between the second end and the third end in series;
two input ends of the voltage detection circuit are respectively connected with the second end and the third end;
the output end of the voltage detection circuit outputs the detection voltage and is connected with the input end of the processor;
the first output end of the processor is connected with the fourth end;
the second output end of the processor is connected with the control end of the switch;
the processor is used for controlling the switch to be switched on or switched off and outputting the control signal so as to control the boost conversion circuit to work and enable the voltage of the direct-current bus to be increased; and after the voltage of the direct current bus is increased to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system according to the detection voltage output by the voltage detection circuit under the on and off of the switch.
6. The insulation detection device of claim 4 or 5, wherein the processor is further configured to: before the control signal is output, if the detected voltage of the direct current bus is greater than or equal to the expected voltage, calculating to obtain the insulation impedance of a photovoltaic array in the photovoltaic power generation system directly according to the detection voltage output by the voltage detection circuit under the condition that the switch is turned on and off.
7. The insulation detection apparatus as claimed in any one of claims 2 to 5, wherein the processor is integrated into a controller in the inverter; or the processor is a digital signal processor DSP based on a single chip microcomputer or an ARM processor.
8. The insulation detection device of claim 7, wherein said voltage detection circuit is an analog-to-digital converter (ADC).
9. An inverter, comprising: an inverter circuit and the insulation detecting device according to any one of claims 1 to 8.
10. The inverter of claim 9, further comprising: at least one boost converter circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710398983.2A CN106997008B (en) | 2017-05-31 | 2017-05-31 | Insulation detection device and inverter |
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| CN201710398983.2A CN106997008B (en) | 2017-05-31 | 2017-05-31 | Insulation detection device and inverter |
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| CN108306335B (en) * | 2018-03-02 | 2020-07-07 | 阳光电源股份有限公司 | Photovoltaic power generation system, inverter, grid-connected operation control method and device thereof |
| DE102018217116B3 (en) * | 2018-10-08 | 2020-03-12 | Volkswagen Aktiengesellschaft | High-voltage system and method for monitoring insulation faults in a high-voltage system |
| WO2021012191A1 (en) * | 2019-07-23 | 2021-01-28 | 深圳欣锐科技股份有限公司 | Insulation detection circuit, mainboard, and related device |
| CN112444706A (en) * | 2019-08-28 | 2021-03-05 | 台达电子企业管理（上海）有限公司 | Insulation monitoring device applied to power system and power system |
| CN110646672A (en) * | 2019-09-17 | 2020-01-03 | 珠海格力电器股份有限公司 | Converter power-on control circuit and method capable of being controlled in real time and converter equipment |
| CN112924753B (en) * | 2019-12-06 | 2022-09-16 | 苏州阿特斯阳光电力科技有限公司 | Detection apparatus for photovoltaic array is to ground insulation resistance |
| CN112924752A (en) * | 2019-12-06 | 2021-06-08 | 台达电子企业管理（上海）有限公司 | Insulation impedance detection circuit and insulation impedance detection method of photovoltaic inverter system |
| CN112083229B (en) * | 2020-09-04 | 2023-04-11 | 爱士惟科技股份有限公司 | Ground insulation impedance detection circuit and method of photovoltaic inverter |
| CN112327055B (en) * | 2020-11-09 | 2024-05-14 | 爱士惟新能源技术(扬中)有限公司 | Insulation impedance detection circuit and method for photovoltaic inverter |
| CN112595895A (en) * | 2020-12-02 | 2021-04-02 | 爱士惟新能源技术(江苏)有限公司 | Insulation impedance detection circuit and method of photovoltaic inverter |
| CN113804543A (en) * | 2021-09-14 | 2021-12-17 | 山东省医疗器械和药品包装检验研究院 | Artificial cochlea implant electrode lead stretchability evaluation method |
| CN114204594B (en) * | 2021-12-07 | 2024-05-14 | 阳光电源股份有限公司 | Grid-connected system and insulation resistance detection method |
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