Bidirectional current detection circuit

Abstract

The utility model discloses a bidirectional current detection circuit, and belongs to the technical field of current detection. The bidirectional current detection circuit comprises a current transformer, a connection module and a detection module, the current transformer is used for being connected with the power circuit, the connection module is connected with the current transformer, and the detection module is connected with the connection circuit. The bidirectional current detection circuit can share a part of electronic components while realizing a function of detecting currents in two different directions, so that the complexity of the detection circuit is reduced, the bidirectional current detection circuit does not need to be connected with windings at two positions of the power circuit, and the accommodating space required by the electronic components corresponding to the detection circuit is relatively small.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of current detection, and in particular to a bidirectional current detection circuit. BACKGROUND

[0002] With the development of photovoltaic energy storage, photovoltaic energy storage products are required to have the function of bidirectional conversion of electric energy. Such bidirectional converter not only can reduce the complexity of the circuit, reduce the volume, but also can effectively reduce the cost. However, in the working process of the bidirectional converter, due to the change of the direction of the current, in order to detect the current in the bidirectional converter, the detection circuit should have the ability of bidirectional current detection.

[0003] In the related art, the current is usually detected by using a current transformer. The detection method using a single current transformer cannot realize the ability of detecting positive and negative polarity currents, and usually only two current transformers are used to realize the detection of bidirectional current of the bidirectional current circuit.

[0004] The scheme of using two current transformers leads to high cost and complexity of the detection circuit, and requires a large space. SUMMARY

[0005] The embodiments of the present disclosure provide a bidirectional current detection circuit, which can solve the above technical problems in the related art. The technical solution is as follows:

[0006] In a first aspect, a bidirectional current detection circuit is provided, which includes a current transformer, a connection module and a detection module.

[0007] The current transformer has a first primary winding, a first secondary winding and a second secondary winding, and the first primary winding is connected with the power circuit.

[0008] The connection module is connected with the first secondary winding, the second secondary winding and the detection module respectively, and the connection module is configured to: in a case where the current direction of the first primary winding is a first direction, transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding; and in a case where the current direction of the first primary winding is a second direction, transmit the current output by the second secondary winding to the detection module and demagnetize the second secondary winding.

[0009] The detection module is configured to determine the current value in the first primary winding based on the detected electric parameters.

[0010] The scheme shown in the present disclosure, the bidirectional current detection circuit realizes the detection function of the current in two different directions while sharing the first primary winding and the detection module, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected to the winding at two places of the power circuit, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0011] In some possible implementation manners, the detection module comprises a sampling load and a voltage detection element arranged in parallel.

[0012] The connection module comprises a first diode, a second diode and a third diode, the anode of the first diode is electrically connected to the different name end of the first secondary winding, the cathode of the first diode is electrically connected to the first end of the sampling load, the anode of the second diode is electrically connected to the same name end of the second secondary winding, the cathode of the second diode is electrically connected to the first end of the sampling load, the anode of the third diode is electrically connected to the second end of the sampling load, and the cathode of the third diode is electrically connected to the same name end of the first secondary winding and the different name end of the second secondary winding.

[0013] In some possible implementation manners, the connection module further comprises a first load and a second load, the first load is connected in parallel with the first secondary winding, and the second load is connected in parallel with the second secondary winding.

[0014] In a second aspect, a bidirectional current detection circuit is provided, comprising a current transformer, a connection module and a detection module.

[0015] The current transformer has a first primary winding, a second primary winding, a switching circuit and a first secondary winding, the first primary winding and the second primary winding are connected to a power circuit, the switching circuit is connected to the first primary winding, the second primary winding and the power circuit respectively, the switching circuit is configured to: in the case that the current direction of the power circuit is a first direction, connect the first primary winding to the power circuit, in the case that the current direction of the power circuit is a second direction, connect the second primary winding to the power circuit, and in the case that the current direction of the power circuit is the first direction and the second direction respectively, the induced current directions of the first secondary winding are the same.

[0016] The connection module is connected to the first secondary winding and the detection module respectively, and the connection module is configured to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding.

[0017] The detection module is configured to determine the current value in the power circuit based on the detected electrical parameters.

[0018] The scheme shown in the present disclosure, the bidirectional current detection circuit realizes the detection function of the current in two different directions by switching the first primary winding and the second primary winding through the switching circuit, meanwhile, the first secondary winding, the connection module and the detection module are shared, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected to the winding at two places of the power circuit, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0019] In some possible implementation manners, the switching circuit comprises a first switch, a second switch and a controller.

[0020] The first switch is connected to the opposite-phase end of the first primary winding and the power circuit respectively.

[0021] The second switch is connected to the same-phase end of the second primary winding and the power circuit respectively.

[0022] The controller is electrically connected with the first switch and the second switch, and the controller is configured to control the conduction or turn-off of the first switch and the second switch based on the current direction of the power circuit.

[0023] In some possible implementation manners, the first switch and the second switch are one of a relay, a MOS tube and an IGBT tube.

[0024] In some possible implementation manners, the switching circuit comprises a fourth diode and a fifth diode.

[0025] The positive electrode of the fourth diode is connected to the opposite-phase end of the first primary winding, and the negative electrode of the fourth diode is connected to the power circuit.

[0026] The positive electrode of the fifth diode is connected to the power circuit, and the negative electrode of the fifth diode is connected to the same-phase end of the second primary winding.

[0027] In some possible implementation manners, the detection module comprises a sampling load and a voltage detection element arranged in parallel, one end of the sampling load is connected to the opposite-phase end of the first secondary winding.

[0028] The connection module comprises a first diode and a first load, the anode of the first diode is connected to the same-phase end of the first secondary winding, the cathode of the first diode is connected to the other end of the sampling load, and the first load is connected to the first secondary winding in parallel.

[0029] In a third aspect, a bidirectional current detection circuit is provided, comprising a current transformer, a connection module, a detection module and a control module.

[0030] The current transformer has a first primary winding and a first secondary winding, and the first primary winding is connected with the power circuit;

[0031] The connection module is connected with the first secondary winding and the detection module respectively;

[0032] The detection module is configured to determine the current value in the first primary winding based on the detected electrical parameter;

[0033] The control module is electrically connected with the connection module, and the control module is configured to control the first connection state of the connection module to be turned on to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding when the current direction of the power circuit is a first direction, and control the second connection state of the connection module to be turned on to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding when the current direction of the power circuit is a second direction.

[0034] The scheme shown in the present disclosure switches the connection state of the connection module by the control module to realize the detection function of the current in two different directions, and meanwhile, the first primary winding, the first secondary winding and the detection module are shared, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected with the windings at two places of the power circuit, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0035] In some possible implementation manners, the detection module includes a sampling load and a voltage detection element arranged in parallel, one end of the sampling load is connected with one end of the first secondary winding;

[0036] The connection module includes a first diode, a second diode, a first switch tube and a second switch tube;

[0037] The cathode of the first diode is connected with the other end of the first secondary winding;

[0038] The anode of the second diode is connected with the anode of the first diode, and the cathode of the second diode is connected with the other end of the sampling load;

[0039] The first switch tube is connected with the first diode in parallel and is electrically connected with the control module;

[0040] The second switch tube is connected with the second diode in parallel and is electrically connected with the control module.

[0041] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0043] Figure 1 is one of the circuit schematic diagrams of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0044] Figure 2 is one of the current schematic diagrams of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0045] Figure 3 is the second current schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0046] Figure 4 is the second circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0047] Figure 5 is the third circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0048] Figure 6 is the fourth circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0049] Figure 7 is the fifth circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0050] Figure 8 is the sixth circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0051] Figure 9 is the third current schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0052] Figure 10 is the fourth current schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0053] Figure 11 is the seventh circuit schematic diagram of the bidirectional current detection circuit provided by the embodiments of the present disclosure.

[0054] Figure 12 is the circuit schematic diagram of the bidirectional current detection circuit using a current transformer in the related art.

[0055] Reference signs:

[0056] 1. A current transformer, 11, a first primary winding, 12, a first secondary winding, 13, a second secondary winding, 14, a second primary winding, 15, a switching circuit, 151, a first switch, 152, a second switch, 153, a controller, 154, a fourth diode, 155, a fifth diode;

[0057] 2. A connection module, 21, a first diode, 22, a second diode, 23, a third diode, 24, a first load, 25, a second load, 26, a first switch tube, 27, a second switch tube, 28, a sixth diode, 29, a capacitor;

[0058] 3. A detection module, 31, a sampling load, 32, a voltage detection element;

[0059] 4. A control module;

[0060] 100. A power circuit.

[0061] The specific embodiments of the present disclosure have been shown in the above drawings, and will be described in more detail hereinafter. These drawings and the written description are not intended to restrict the scope of the present disclosure concept in any way, but to illustrate the present disclosure concept to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0063] With the development of photovoltaic energy storage, photovoltaic energy storage products are required to have the function of bidirectional conversion of electric energy. Such a bidirectional converter not only can reduce the complexity of the circuit, reduce the volume, but also can effectively reduce the cost. However, in the working process of the bidirectional converter, due to the change of the direction of the current, in order to detect the current in the bidirectional converter, the detection circuit should have the ability of bidirectional current detection.

[0064] In the related art, the current is usually detected by using a current transformer. In order to ensure the measurement accuracy and performance of the current transformer, the winding of the current transformer needs to be subjected to corresponding demagnetization treatment, so that the conduction of the connection circuit connected with the current transformer has unidirectionality. Therefore, the detection method using a single current transformer cannot realize the ability of detecting positive and negative polarity currents.

[0065] Referring to Figure 12 As shown in the figure, two current transformers are usually used to detect the bidirectional current of the bidirectional current circuit, and the scheme includes two detection systems, each detection system including a current transformer 1, a connection module 2 and a detection module 3.

[0066] Referring toFigure 12 As shown, in the case that the current direction of the power circuit 100 is the first direction (for example, counterclockwise), the current flows into the first primary winding 11 of the detection system on the right from the non-identical end and flows out from the identical end, the induced current flows out from the non-identical end of the first secondary winding 12, and flows through the first diode 21 and the sampling load 31 and flows to the identical end of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and the size of the second direction current is calculated based on the collected voltage value, the impedance of the sampling load 31 and the parameters of the current transformer 1. At the same time, the current flows into the first primary winding 11 of the detection system on the left from the non-identical end and flows out from the identical end, and the induced current flows out from the non-identical end of the first secondary winding 12, but is reversely cut off by the first diode 21, so the left detection system does not detect the first direction current.

[0067] Based on the same principle, in the case that the current direction of the power circuit 100 is the second direction (for example, clockwise), the right detection system does not detect, and the left detection system can calculate the size of the first direction current according to the voltage value collected by the corresponding voltage detection element 32, the impedance of the sampling load 31 and the parameters of the current transformer 1.

[0068] The scheme of using two current transformers leads to high cost and complexity of the detection circuit, and the required accommodation space of the corresponding electronic elements of the detection circuit is large.

[0069] To solve the above technical problems, the embodiment of the present disclosure provides a bidirectional current detection circuit.

[0070] Embodiment one:

[0071] Reference Figure 1 As shown, in some embodiments, the bidirectional current detection circuit includes a current transformer 1, a connection module 2 and a detection module 3. The current transformer 1 has a first primary winding 11, a first secondary winding 12 and a second secondary winding 13, and the first primary winding 11 is connected with a power circuit 100.

[0072] The connection module 2 is connected with the first secondary winding 12, the second secondary winding 13 and the detection module 3 respectively, and the connection module 2 is used for: in the case that the current direction of the first primary winding 11 is the first direction, transmitting the current output by the first secondary winding 12 to the detection module 3 and demagnetizing the first secondary winding 12, and in the case that the current direction of the first primary winding 11 is the second direction, transmitting the current output by the second secondary winding 13 to the detection module 3 and demagnetizing the second secondary winding 13. The detection module 3 is used for determining the current value in the first primary winding 11 based on the detected electrical parameters.

[0073] Thus, compared with the detection circuit in the related art, the bidirectional current detection circuit in the embodiment of the present disclosure shares the first primary winding 11 and the detection module 3 while realizing the detection function of the current in two different directions, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected to the winding at two places of the power circuit 100, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0074] In some embodiments, the detection module 3 includes a sampling load 31 and a voltage detection element 32 arranged in parallel. The connection module 2 includes a first diode 21, a second diode 22, and a third diode 23, the anode of the first diode 21 is electrically connected to the non-identical end of the first secondary winding 12, the cathode of the first diode 21 is electrically connected to the first end of the sampling load 31, the anode of the second diode 22 is electrically connected to the identical end of the second secondary winding 13, the cathode of the second diode 22 is electrically connected to the first end of the sampling load 31, the anode of the third diode 23 is electrically connected to the second end of the sampling load 31, and the cathode of the third diode 23 is electrically connected to the identical end of the first secondary winding 12 and the non-identical end of the second secondary winding 13.

[0075] Thus, in the case where the current direction of the first primary winding 11 is the first direction, referring to Figure 2 , the current in the power circuit 100 flows from the non-identical end to the identical end of the first primary winding 11, the induced current flows out from the non-identical end of the first secondary winding 12, and flows through the first diode 21, the sampling load 31, and the third diode 23, and flows to the identical end of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and calculates the size of the current in the first direction based on the collected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1. At the same time, the induced current flows out from the non-identical end of the second secondary winding 13, and the flow direction of the induced current is opposite to the conduction direction of the third diode 23, so the induced current is cut off.

[0076] Based on the same principle, in the case where the current direction of the first primary winding 11 is the second direction, referring to Figure 3 , the current in the power circuit 100 flows from the identical end to the non-identical end of the first primary winding 11, the induced current flows out from the identical end of the second secondary winding 13, and flows through the second diode 22, the sampling load 31, and the third diode 23, and flows to the non-identical end of the second secondary winding 13. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and calculates the size of the current in the second direction based on the collected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1. At the same time, the induced current flows out from the identical end of the first secondary winding 12, and the flow direction of the induced current is opposite to the conduction direction of the third diode 23, so the induced current is cut off.

[0077] Therefore, in the case that the current direction of the first primary winding 11 is the first direction, the first secondary winding 12 is coupled with the first primary winding 11, and the first secondary winding 12 induces current to output to the detection module 3; in the case that the current direction of the first primary winding 11 is the second direction, the second secondary winding 13 is coupled with the first primary winding 11, and the second secondary winding 13 induces current to output to the detection module 3.

[0078] In some embodiments, the connection module 2 further comprises a first load 24 and a second load 25, the first load 24 is connected in parallel with the first secondary winding 12, and the second load 25 is connected in parallel with the second secondary winding 13.

[0079] Demagnetization refers to eliminating or weakening the residual magnetic flux in the core of the current transformer 1 to ensure the accuracy and stability of the operation of the current transformer 1.

[0080] The impedance of the first load 24 is 10-20 times the impedance of the first secondary winding 12, the second secondary winding 13 is short-circuited, and the power frequency current is passed through the first primary winding 11, so that the current gradually increases from zero to a certain value (for example: 1.2 times the rated current), and then uniformly and slowly decreases to zero. During this process, due to the existence of the large impedance of the first load 24, the change speed of the current is limited, thereby effectively controlling the change of the magnetic flux, and achieving the purpose of demagnetization.

[0081] Based on the same principle, the impedance of the second load 25 is 10-20 times the impedance of the second secondary winding 13, the first secondary winding 12 is short-circuited, and the power frequency current is passed through the first primary winding 11, so that the current gradually increases from zero to a certain value (for example: 1.2 times the rated current), and then uniformly and slowly decreases to zero. During this process, due to the existence of the large impedance of the second load 25, the change speed of the current is limited, thereby effectively controlling the change of the magnetic flux, and achieving the purpose of demagnetization.

[0082] Embodiment two:

[0083] Referring to Figure 4 In some other embodiments, the detection module 3 comprises a sampling load 31 and a voltage detection element 32 connected in parallel. The connection module 2 comprises a first diode 21, a second diode 22, a third diode 23, and a sixth diode 28.

[0084] Anode of the first diode 21 is electrically connected with the homonymic end of the first secondary winding 12, and cathode of the first diode 21 is electrically connected with the first end of the sampling load 31. Anode of the second diode 22 is electrically connected with the homonymic end of the second secondary winding 13, and cathode of the second diode 22 is electrically connected with the first end of the sampling load 31. Anode of the third diode 4 is electrically connected with the second end of the sampling load 31, and cathode of the third diode 4 is electrically connected with the homonymic end of the first secondary winding 12. Anode of the sixth diode 28 is electrically connected with the second end of the sampling load 31, and cathode of the sixth diode 28 is electrically connected with the homonymic end of the second secondary winding 13.

[0085] Compared with the technical solution in the embodiment one, the homonymic end of the first secondary winding 12 and the homonymic end of the second secondary winding 13 do not share the third diode 23, but are respectively provided with the third diode 23 and the sixth diode 28.

[0086] In this way, the failure of the shared diode can be avoided to cause the failure of the whole bidirectional current detection circuit. For example, the third diode 23 fails, and the sixth diode 28 works normally. Although the bidirectional current detection circuit cannot continue to detect the case that the current direction of the first primary winding 11 is the first direction, it can still detect the case that the current direction of the first primary winding 11 is the second direction. Meanwhile, the failed element can be accurately located according to the detection result, which facilitates the maintenance and replacement work of the maintenance personnel.

[0087] Embodiment three:

[0088] Referring to Figure 5 In some embodiments, the bidirectional current detection circuit includes a current transformer 1, a connection module 2 and a detection module 3.

[0089] The current transformer 1 has a first primary winding 11, a second primary winding 14, a switching circuit 15 and a first secondary winding 12. The first primary winding 11 and the second primary winding 14 are connected with a power circuit 100, and the switching circuit 15 is connected with the first primary winding 11, the second primary winding 14 and the power circuit 100 respectively. The switching circuit 15 is used for: in the case that the current direction of the power circuit 100 is a first direction, connecting the first primary winding 11 to the power circuit 100; in the case that the current direction of the power circuit 100 is a second direction, connecting the second primary winding 14 to the power circuit 100; and in the case that the current direction of the power circuit 100 is the first direction and the second direction respectively, the induced current directions of the first secondary winding 12 are the same.

[0090] The connection module 2 is connected with the first secondary winding 12 and the detection module 3 respectively, and the connection module 2 is used for transmitting the current output by the first secondary winding 12 to the detection module 3 and demagnetizing the first secondary winding 12;

[0091] The detection module 3 is configured to determine the current value in the power circuit 100 based on the detected electrical parameter.

[0092] In this way, compared with the detection circuit in the related art, the bidirectional current detection circuit in the embodiment of the present disclosure switches between the first primary winding 11 and the second primary winding 14 through the switching circuit 15 to realize the detection function of the current in two different directions, and meanwhile, the first secondary winding 12, the connection module 2 and the detection module 3 are shared, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected to the windings at two places of the power circuit 100, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0093] Referring to Figure 6 In some embodiments, the switching circuit 15 includes a first switch 151, a second switch 152 and a controller 153.

[0094] The first switch 151 is connected to the non-name end of the first primary winding 11 and the power circuit 100, respectively, the second switch 152 is connected to the name end of the second primary winding 14 and the power circuit 100, respectively, and the controller 153 is electrically connected to the first switch 151 and the second switch 152. The first controller 153 is configured to control the conduction or turn-off of the first switch 151 and the second switch 152 based on the current direction of the power circuit 100.

[0095] The detection module 3 includes a sampling load 31 and a voltage detection element 32 connected in parallel, one end of the sampling load 31 is connected to the non-name end of the first secondary winding 12. The connection module 2 includes a first diode 21 and a first load 24, the anode of the first diode 21 is connected to the name end of the first secondary winding 12, the cathode of the first diode 21 is connected to the other end of the sampling load 31, and the first load 24 is connected to the first secondary winding 12 in parallel. The first load 24 is configured to demagnetize the core in the current transformer 1.

[0096] In this way, in the case that the current direction of the power circuit 100 at the position of the current transformer is the first direction (for example, counterclockwise), the controller 153 controls the first switch 151 to be turned off and the second switch 152 to be turned on, the current flows into the name end of the second primary winding 14 and flows out of the non-name end, the induced current corresponding to the current flows out of the name end of the first secondary winding 12, and flows through the first diode 21 and the sampling load 31, and flows to the non-name end of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and calculates the size of the current in the first direction based on the collected voltage value, the impedance of the sampling load 31 and the parameters of the current transformer 1.

[0097] When the current flow direction of the power circuit 100 at the location of the current transformer is in the second direction (clockwise as an example), the controller 153 controls the first switch 151 to turn on and the second switch 152 to turn off. Current flows in from the same-name terminal of the first primary winding 11 and flows out from the opposite-name terminal. The induced current flows out from the same-name terminal of the first secondary winding 12, passes through the first diode 21 and the sampling load 31, and flows to the opposite-name terminal of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31 and calculates the magnitude of the current in the first direction from the collected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1.

[0098] In some embodiments, the first switch 151 and the second switch 152 are both one of relays, MOSFETs, and IGBTs, and can be matched and limited according to parameters such as the required switching frequency of the first switch 151 and the current value flowing through the opening.

[0099] In some embodiments, the connection module 2 further includes a capacitor 29, which is connected in parallel with the sampling load 31. The capacitor 29 is used for filtering the detection module 3. When the voltage of the sampling load 31 is higher than the voltage across the capacitor 29, the capacitor 29 charges; when the voltage of the sampling load 31 is lower than the voltage across the capacitor 29, the capacitor 29 discharges. The charging and discharging process of the capacitor 29 can suppress the voltage fluctuation of the sampling load 31, thereby achieving the purpose of filtering.

[0100] Example 4:

[0101] Reference Figure 7 As shown, in some other embodiments, the switching circuit 15 includes a fourth diode 154 and a fifth diode 155. The positive terminal of the fourth diode 154 is connected to the opposite terminal of the first primary winding 11, the negative terminal of the fourth diode 154 is connected to the power circuit 100, the positive terminal of the fifth diode 155 is connected to the power circuit 100, and the negative terminal of the fifth diode 155 is connected to the same terminal of the second primary winding 14.

[0102] The detection module 3 includes a sampling load 31 and a voltage detection element 32 connected in parallel. One end of the sampling load 31 is connected to the opposite-name terminal of the first secondary winding 12. The connection module 2 includes a first diode 21 and a first load 24. The anode of the first diode 21 is connected to the same-name terminal of the first secondary winding 12, and the cathode of the first diode 21 is connected to the other end of the sampling load 31. The first load 24 is connected in parallel with the first secondary winding 12. The first load 24 is used to demagnetize the iron core in the current transformer 1.

[0103] In this way, when the current flowing through the power circuit 100 at the location of the current transformer 1 is in the first direction (for example, counterclockwise), the current flows through the fifth diode 155 and flows into the same end of the second primary winding 14 and flows out of the different end of the second primary winding 14. The induced current flows out of the same end of the first secondary winding 12, flows through the first diode 21 and the sampling load 31, and flows to the different end of the first secondary winding 12. The voltage detection element 32 detects the voltage across the sampling load 31, and calculates the current value in the first direction based on the detected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1.

[0104] When the current flowing through the power circuit 100 at the location of the current transformer 1 is in the second direction (for example, clockwise), the current flows into the same end of the first primary winding 11 and flows out of the different end of the first primary winding 11 and flows through the fourth diode 154. The induced current flows out of the same end of the first secondary winding 12, flows through the first diode 21 and the sampling load 31, and flows to the different end of the first secondary winding 12. The voltage detection element 32 detects the voltage across the sampling load 31, and calculates the current value in the first direction based on the detected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1.

[0105] In some embodiments, the connection module 2 further includes a capacitor 29, which is connected in parallel with the sampling load 31. The capacitor 29 is used for filtering of the detection module 3. When the voltage of the sampling load 31 is higher than the voltage across the capacitor 29, the capacitor 29 is charged. When the voltage of the sampling load 31 is lower than the voltage across the capacitor 29, the capacitor 29 is discharged. The charging and discharging process of the capacitor 29 can suppress the fluctuations of the voltage of the sampling load 31, thereby achieving the purpose of filtering.

[0106] Embodiment Five:

[0107] Referring to Figure 8 In some embodiments, the bidirectional current detection circuit includes a current transformer 1, a connection module 2, a detection module 3, and a control module 4.

[0108] The current transformer 1 has a first primary winding 11 and a first secondary winding 12, and the first primary winding 11 is connected to the power circuit 100. The connection module 2 is connected to the first secondary winding 12, the detection module 3, respectively. The detection module 3 is used to determine the current value in the first primary winding 11 based on the detected electrical parameters.

[0109] The control module 4 is electrically connected with the connection module 2, and the control module 4 is configured to: in a case where the current direction of the power circuit 100 is a first direction, control the first connection state of the connection module 2 to be turned on, so as to transmit the current output by the first secondary winding 12 to the detection module 3 and demagnetize the first secondary winding 12; and in a case where the current direction of the power circuit 100 is a second direction, control the second connection state of the connection module 2 to be turned on, so as to transmit the current output by the first secondary winding 12 to the detection module 3 and demagnetize the first secondary winding 12.

[0110] In this way, compared with the detection circuit in the related art, the bidirectional current detection circuit in the embodiment of the present disclosure switches the connection state of the connection module 2 through the control module 4, so as to realize the detection function of the current in two different directions, and meanwhile, the first primary winding 1, the first secondary winding 12 and the detection module 3 are shared, thereby reducing the complexity of the detection circuit, and the detection circuit does not need to be connected to the windings at two places of the power circuit 100, thereby the required accommodation space of the electronic elements corresponding to the detection circuit is smaller.

[0111] Referring to FIG. 1, Figure 9 In some embodiments, the detection module 3 includes a sampling load 31 and a voltage detection element 32 which are connected in parallel, one end of the sampling load 31 is connected with one end of the first secondary winding 12.

[0112] The connection module 2 includes a first diode 21, a second diode 22, a first switch tube 26 and a second switch tube 27, the cathode of the first diode 21 is connected with the other end of the first secondary winding 12, the anode of the second diode 22 is connected with the anode of the first diode 21, the cathode of the second diode 22 is connected with the other end of the sampling load 31, the first switch tube 26 is connected with the first diode 21 in parallel and is electrically connected with the control module 4, and the second switch tube 27 is connected with the second diode 22 in parallel and is electrically connected with the control module 4.

[0113] In a case where the current direction of the first primary winding 11 is a first direction (for example, counterclockwise), referring to FIG. 2, Figure 9 The control module 4 controls the first switch tube 26 to be turned on, and the current in the power circuit 100 flows from the opposite end of the first primary winding 11 to the same end, the induced current flows out from the opposite end of the first secondary winding 12, and then flows through the first switch tube 26, the second diode 22, the sampling load 31 and then flows to the same end of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and the size of the current in the first direction is calculated according to the collected voltage value, the impedance of the sampling load 31 and the parameters of the current transformer 1.

[0114] In a case where the current direction of the first primary winding 11 is a second direction (for example, clockwise), referring to FIG. 3, Figure 10As shown, the control module 4 controls the second switch tube 27 to be turned on, and the current in the power circuit 100 flows from the same name end of the first primary winding 11 to the different name end, and the corresponding induced current flows out from the same name end of the first secondary winding 12, and then flows through the sampling load 31, the second switch tube 27, the first diode 21, and finally flows to the different name end of the first secondary winding 12. The voltage detection element 32 detects the voltage on both sides of the sampling load 31, and calculates the size of the first direction current according to the collected voltage value, the impedance of the sampling load 31, and the parameters of the current transformer 1.

[0115] In some embodiments, the connection module 2 further comprises a first load 24, which is connected in parallel with the first secondary winding 12, and the first load 24 is used for demagnetizing the core in the current transformer 1.

[0116] In some embodiments, the voltage detection element 32 can include an operational amplifier and a bias voltage source, the bias voltage source can adjust the value range of the voltage drop on both sides of the sampling load 31 to a positive range, and the operational amplifier can amplify the voltage value adjusted by the bias voltage source to a certain multiple and output, and the subsequent test personnel can calculate the current size of the power circuit 100 according to the output voltage value and the parameters of the operational amplifier and the bias voltage source.

[0117] In the description of the present specification, the description of the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the different embodiments or examples described in the present specification and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0118] It can be understood that "multiple" in the present disclosure means two or more, and other quantifiers are similar. The association relationship of the associated objects is described, which means that there can be three relationships, for example, A and / or B, which can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. The character " / " generally represents that the associated objects before and after are in an "or" relationship. The singular form of "a", "said" and "the" is also intended to include the plural form, unless the context clearly indicates otherwise.

[0119] It will be further understood that the terms "first", "second", etc. are used to describe various information but should not be construed as limiting the information to these terms only. These terms are used only to distinguish one from another instance of the same type of information. In practice, the "first", "second", etc. designations can be interchanged. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present disclosure.

[0120] It will be further understood that the terms "center", "longitudinal", "lateral", "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate relative or positional relationships based on the orientations or positions shown in the drawings, and are used only to facilitate the description of the embodiments and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and be operated in a particular orientation.

[0121] It will be further understood that, unless otherwise specified and limited, the terms "mount", "connect", "connection", "fixed", and the like should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral molding; can be mechanical connection, can also be electrical connection or can communicate with each other; can be direct connection between the two without other components, or can be indirect connection through intermediate medium, can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0122] It will be further understood that, although the operations in the embodiments of the present disclosure are described in a specific order in the drawings, it should not be construed that the operations must be performed in the specific order or in a serial order, or that all the shown operations must be performed to obtain the desired results. In a specific environment, multi-tasking and parallel processing can be advantageous.

[0123] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the aspects disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure following the general principles thereof and including modifications and equivalents of the present disclosure. The specification and examples are to be regarded as illustrative only, and the true scope and spirit of the present disclosure are indicated by the scope of the claims.

[0124] It should be understood that the present disclosure is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the present disclosure. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A bidirectional current sensing circuit, characterized by, The bidirectional current detection circuit comprises a current transformer, a connection module and a detection module; The current transformer has a first primary winding, a first secondary winding and a second secondary winding, and the first primary winding is connected with a power circuit; The connection module is connected with the first secondary winding, the second secondary winding and the detection module respectively, and the connection module is configured to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding when the current direction of the first primary winding is a first direction, and transmit the current output by the second secondary winding to the detection module and demagnetize the second secondary winding when the current direction of the first primary winding is a second direction; The detection module is configured to determine the current value in the first primary winding based on the detected electrical parameters.

2. The bidirectional current detection circuit according to claim 1, wherein The detection module comprises a sampling load and a voltage detection element arranged in parallel; The connection module comprises a first diode, a second diode and a third diode, the anode of the first diode is electrically connected with the non-pole end of the first secondary winding, the cathode of the first diode is electrically connected with the first end of the sampling load, the anode of the second diode is electrically connected with the pole end of the second secondary winding, the cathode of the second diode is electrically connected with the first end of the sampling load, the anode of the third diode is electrically connected with the second end of the sampling load, and the cathode of the third diode is electrically connected with the pole end of the first secondary winding and the non-pole end of the second secondary winding.

3. The bidirectional current detection circuit according to claim 2, wherein The connection module further comprises a first load and a second load, the first load is connected with the first secondary winding in parallel, and the second load is connected with the second secondary winding in parallel.

4. A bidirectional current sensing circuit, characterized by, The bidirectional current detection circuit comprises a current transformer, a connection module and a detection module; The current transformer has a first primary winding, a second primary winding, a switching circuit and a first secondary winding, the first primary winding and the second primary winding are connected with a power circuit, the switching circuit is connected with the first primary winding, the second primary winding and the power circuit respectively, and the switching circuit is configured to connect the first primary winding to the power circuit when the current direction of the power circuit is a first direction, connect the second primary winding to the power circuit when the current direction of the power circuit is a second direction, and make the induced current directions of the first secondary winding the same when the current directions of the power circuit are the first direction and the second direction respectively; The connection module is connected with the first secondary winding and the detection module respectively, and the connection module is configured to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding; The detection module is configured to determine the current value in the power circuit based on the detected electrical parameters.

5. The bidirectional current detection circuit according to claim 4, wherein the switching circuit comprises a first switch, a second switch and a controller; the first switch is connected with the opposite end of the first primary winding and the power circuit respectively; the second switch is connected with the same end of the second primary winding and the power circuit respectively; the controller is electrically connected with the first switch and the second switch, and the controller is configured to control the first switch and the second switch to be turned on or turned off based on the current direction of the power circuit.

6. The bidirectional current detection circuit according to claim 5, wherein the first switch and the second switch are one of a relay, a MOS tube and an IGBT tube.

7. The bidirectional current detection circuit according to claim 4, wherein the switching circuit comprises a fourth diode and a fifth diode; the positive electrode of the fourth diode is connected with the opposite end of the first primary winding, and the negative electrode of the fourth diode is connected with the power circuit; the positive electrode of the fifth diode is connected with the power circuit, and the negative electrode of the fifth diode is connected with the same end of the second primary winding.

8. The bidirectional current detection circuit according to claim 5 or 7, wherein the detection module comprises a sampling load and a voltage detection element connected in parallel, one end of the sampling load is connected with the opposite end of the first secondary winding; the connection module comprises a first diode and a first load, the anode of the first diode is connected with the same end of the first secondary winding, the cathode of the first diode is connected with the other end of the sampling load, and the first load is connected with the first secondary winding in parallel. The bidirectional current detection circuit comprises a current transformer, a connection module, a detection module and a control module; the current transformer has a first primary winding and a first secondary winding, and the first primary winding is connected with a power circuit; the connection module is connected with the first secondary winding and the detection module respectively; the detection module is configured to determine the current value in the first primary winding based on the detected electrical parameters; 9. A bidirectional current sensing circuit, characterized by, the control module is electrically connected with the connection module, and the control module is configured to control the first connection state of the connection module to be turned on when the current direction of the power circuit is a first direction, and control the second connection state of the connection module to be turned on when the current direction of the power circuit is a second direction, so as to transmit the current output by the first secondary winding to the detection module and demagnetize the first secondary winding.

10. The bidirectional current detection circuit according to claim 9, wherein the detection module comprises a sampling load and a voltage detection element connected in parallel, one end of the sampling load is connected with one end of the first secondary winding; the connection module comprises a first diode, a second diode, a first switch tube and a second switch tube; the cathode of the first diode is connected with the other end of the first secondary winding; ​ ​ ​ ​ ​ An anode of the second diode is connected with an anode of the first diode, and a cathode of the second diode is connected with the other end of the sampling load; The first switch tube is connected with the first diode in parallel, and is electrically connected with the control module; The second switch tube is connected with the second diode in parallel, and is electrically connected with the control module.

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