CN117767698A

CN117767698A - Power converter, control method thereof and energy storage system

Info

Publication number: CN117767698A
Application number: CN202311551456.2A
Authority: CN
Inventors: 李贤哲
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2023-11-17
Filing date: 2023-11-17
Publication date: 2024-03-26

Abstract

The application provides a power converter, a control method thereof and an energy storage system. The input end of the power conversion circuit is connected with the first bus, and the output end of the power conversion circuit is connected with the second bus. The integrated inductor comprises a first winding, a second winding and a third winding, wherein the first winding and the second winding are connected with a first bus or a second bus, the first winding and the second winding form a common-mode inductor coil and are used for common-mode filtering, and the third winding is connected with a comparison circuit and is used for detecting leakage current. The comparison circuit outputs a first signal to the controller according to the induction current signal output by the third winding; the controller generates and outputs a second signal after receiving the first signal, wherein the second signal is used for indicating the power conversion circuit to stop outputting to the second bus so as to complete the corresponding leakage current protection function.

Description

Power converter, control method thereof and energy storage system

Technical Field

The application relates to the technical field of energy, in particular to a power converter, a control method thereof and an energy storage system.

Background

At present, in energy storage scenes such as a communication battery, a data center energy storage battery, a vehicle-mounted power battery and a photovoltaic energy storage battery or a power supply circuit with a conversion function, a residual current detection circuit is required to be added for leakage current protection, so that power failure caused by leakage is avoided. In addition, in the energy storage device or the power supply circuit with the power conversion function, a filter circuit with a common-mode inductance needs to be added, and the common-mode inductance can filter the common-mode component so as to ensure the electromagnetic compatibility (electromagnetic compatibility, EMC) performance of the energy storage device or the power supply circuit.

The residual current detection device (residual current device, RCD) is used for detecting residual current in a circuit, namely leakage current in time, and judging whether leakage occurs or not according to the magnitude of the leakage current so as to avoid danger caused by the leakage. The residual current detection includes the following three types: (1) type A residual current detection: only sinusoidal alternating current signals can be detected; (2) AC-type residual current detection: the sinusoidal alternating current signal and the pulsating direct current signal can be detected; (3) type B residual current detection: sinusoidal ac signals, pulsating dc signals and dc signals may be detected. The residual current detection can adopt the following three detection modes: (1) current transformer (current transformer, CT): the method can be used for detecting the A-type residual current, and measurement cannot be completed in a direct current scene; (2) hall sensor: the cost is high, the magnetic field interference of external large current is easy to occur, and the detection error of the Hall transformer is increased when the measured current contains a large direct current component due to the magnetic core hysteresis; (3) fluxgate sensor: the cost is higher and the volume is larger.

Therefore, currently, under the condition of having both the residual current detection and the common mode filtering requirements, two magnetic devices for the residual current detection and for the common mode filtering are required to be respectively arranged in the power conversion device, the two magnetic devices increase the device cost, occupy a larger area of the circuit board, and increase the loss of the single board.

Disclosure of Invention

The application provides a power converter, a control method thereof and an energy storage system, which are used for saving cost, reducing the area of a circuit board occupied by a magnetic device and reducing single board loss.

In a first aspect, embodiments of the present application provide a power converter that includes a power conversion circuit, an integrated inductor, a comparison circuit, and a controller. The input end of the power conversion circuit is used for being connected with a first bus, and the first bus can be connected with the output end of the energy storage device, the power supply or other circuits; the output end of the power conversion circuit is used for being connected with a second bus, and the second bus can be connected with load equipment or a power grid. The power conversion circuit is used for outputting the electric energy provided by the first bus to the second bus after power conversion. The integrated inductor is connected in series between the input end of the power conversion circuit and the first bus or between the output end of the power conversion circuit and the second bus. The integrated inductor includes a first winding, a second winding, and a third winding. The integrated inductor is a magnetic device integrated with common mode filtering and leakage current detection, wherein the first winding and the second winding form a common mode inductor coil and are used for common mode filtering, and the third winding is connected with the comparison circuit and is used for detecting leakage current. In the implementation, the first winding and the second winding may be connected to the first bus, where the integrated inductor is used as an input filter and the integrated inductor uses the third winding to detect whether the input end of the power conversion circuit has a leakage current. Or the first winding and the second winding can be connected with the second bus, the integrated inductor is used as output filtering, and the integrated inductor adopts the third winding to detect whether the output end of the power conversion circuit has leakage current or not. The comparison circuit is connected with the controller and is used for determining whether leakage current protection is needed according to the induction current signal output by the third winding, and outputting a first signal to the controller when judging that the leakage current protection is needed; the controller generates and outputs a second signal after receiving the first signal, wherein the second signal is used for indicating the power conversion circuit to stop outputting to the second bus so as to complete the corresponding leakage current protection function.

In the application, the common mode inductor for filtering and the detection inductor for residual current protection are integrated into the same inductor, so that the use quantity of the magnetic devices is reduced, the cost is saved, the circuit board area occupied by the magnetic devices is reduced, the single board loss is reduced, the corresponding circuits are matched, and the functions of common mode filtering and residual current protection are realized.

In some embodiments of the present application, when the comparison circuit determines that the voltage amplitude of the induced current signal is greater than the first threshold, and determines that the leakage current abnormality needs to be protected by the leakage current, the comparison circuit outputs a first signal to the controller, where the first signal may specifically be a high level signal. Accordingly, when the comparison circuit determines that the voltage amplitude of the induced current signal is smaller than the first threshold value, the comparison circuit may output a low level signal to the controller. The comparison circuit only needs to judge whether leakage current protection is needed according to whether the induced current signal is larger than a first threshold value, the leakage current is not needed to be accurately detected, and cost, occupied area and module loss can be reduced.

In some embodiments of the present application, to avoid the interference triggering the erroneous determination, the controller may generate and output the second signal when it is determined that the number of the received first signals is greater than the second threshold value in the first period. For example, the controller may generate and output the second signal when it receives the first signal 1 thousand times or more in 1 second.

In some embodiments of the present application, the controller may output a second signal to the power conversion circuit, where the second signal is used to control the power conversion circuit to stop operating, and stop processing the power conversion circuit, so that the power conversion circuit stops outputting to the second bus.

In other embodiments of the present application, a switch is disposed on the outer side of the power conversion circuit, and the switch may specifically use a relay to implement its function. The controller may also output a second signal to the switch, where the second signal is used to control the switch to be turned off, and cut off the connection between the bus and the power conversion circuit, so that the power conversion circuit stops outputting to the second bus. In particular, the power converter may include a first switch in series with the first bus bar and a second switch in series with the second bus bar. When the integrated inductor is arranged at one side of the input end of the power conversion circuit, namely the integrated inductor is arranged at the input end of the first switch and the input end of the power conversion circuit, the controller can output a second signal to the first switch, and the second signal is used for controlling the first switch to be disconnected. Further, the controller may output a second signal to the first switch and the power conversion circuit at the same time, where the second signal is used to control the power conversion circuit to stop operating and control the first switch to be turned off, and stop the power conversion circuit from outputting to the second bus by performing a shutdown process and an off process on the first switch. When the integrated inductor is arranged at one side of the output end of the power conversion circuit, namely, the integrated inductor is arranged at the output end of the second switch and the output end of the power conversion circuit, the controller can output a second signal to the second switch, and the second signal is used for controlling the second switch to be disconnected. Further, the controller may output a second signal to the second switch and the power conversion circuit at the same time, where the second signal is used to control the power conversion circuit to stop operating and control the second switch to be turned off, and stop the power conversion circuit from outputting to the second bus by performing a shutdown process and an off process on the second switch.

In some embodiments of the present application, the first winding, the second winding, and the third winding may be wound on the same magnetic core, the number of turns and phases of the first winding and the second winding are the same and the winding is reversed, and the number of turns of the third winding is generally greater than the number of turns of the first winding. When normal current flows through the integrated inductor, the currents generate reverse magnetic fields in the first winding and the second winding which are wound in the same phase to cancel each other, and the normal current is mainly influenced by the winding resistance; when common mode current flows through the first winding and the second winding, due to the isotropy of the common mode current, a magnetic field in the same direction is generated in the first winding and the second winding to increase the inductive reactance of the first winding and the second winding, so that the first winding and the second winding show high impedance, a stronger damping effect is generated, the common mode current is attenuated, and the filtering effect is achieved. The third winding is used as a secondary side coil of the integrated inductor, and induced potential is generated under the action of magnetic flux of the magnetic core, so that induced current proportional to leakage current is generated in the secondary loop, namely the third winding. Under normal conditions, the common mode current is very small, when leakage current occurs, the leakage current is output through the first winding and the second winding, larger common mode current is generated, the third winding of the integrated inductor generates induced potential according to magnetic flux generated by the common mode current to generate induced current signals, and the larger the leakage current is, the larger the induced potential generated by the third winding is, namely the induced current is.

In some embodiments of the present application, the power conversion circuit may be a direct current-to-direct current conversion circuit (DC-DC Converter, DCDC) for converting direct current provided by the energy storage device into different voltages by way of boosting or reducing, so as to provide for a subsequent device.

In other embodiments of the present application, the power converter may further include an ac-dc conversion circuit, where an output end of the ac-dc conversion circuit may be connected to an input end of the dc-dc conversion circuit through an integrated inductor; alternatively, the output end of the ac-dc conversion circuit may be directly connected to the input end of the dc-dc conversion circuit, and the output end of the dc-dc conversion circuit is connected to the integrated inductor.

In other embodiments of the present application, the power conversion circuit may also be a dc-to-ac conversion circuit, and may be an energy storage converter (power conversion system, PCS) specifically, the PCS is configured to convert dc power into ac power, and is responsible for ac power grid configuration.

In other embodiments of the present application, the power conversion circuit may specifically include a DCDC and a PCS, where the DCDC is connected between the energy storage device and the PCS, and the PCS is connected to the power grid as a device at a later stage of the DCDC.

In other embodiments of the present application, the power conversion circuit may also be specifically an ac-to-dc conversion circuit, which is configured to convert ac power into dc power, and then may supply power to the load.

In a second aspect, the present application provides an energy storage system, including an energy storage device and the power converter provided in the first aspect, where the energy storage device is connected with the power converter through a first bus, and the power converter is used for outputting electric energy provided by the energy storage device after power conversion. The power converter provided by the embodiment of the application can be widely applied to energy storage scenes such as a communication battery, a data center energy storage battery, a vehicle-mounted power battery, a photovoltaic energy storage battery and the like, and can also be applied to a power circuit with a power conversion function. The common mode inductor for filtering and the detection inductor for residual current protection are integrated into the same inductor in the power converter, so that the use quantity of magnetic devices is reduced, the cost is saved, the circuit board area occupied by the magnetic devices is reduced, the single board loss is reduced, and the functions of common mode filtering and residual current protection are realized simultaneously by matching with corresponding circuits.

In a third aspect, the present application provides a control method of a power converter, where the power converter is the power converter provided in the first aspect. The control method specifically comprises the following steps: the comparison circuit outputs a first signal to the controller according to the induction current signal output by the third winding; the controller generates and outputs a second signal according to the first signal, wherein the second signal is used for indicating the power conversion circuit to stop outputting to the second bus.

In some embodiments of the present application, the comparing circuit outputs a first signal to the controller according to the induced current signal output by the third winding, and may specifically include: when the comparison circuit judges that the voltage amplitude of the induced current signal is larger than a first threshold value, and when the leakage current abnormality is determined to need leakage current protection, the comparison circuit outputs a first signal to the controller, and the first signal can be a high-level signal. Accordingly, when the comparison circuit determines that the voltage amplitude of the induced current signal is smaller than the first threshold value, the comparison circuit may output a low level signal to the controller. The comparison circuit only needs to judge whether leakage current protection is needed according to whether the induced current signal is larger than a first threshold value, the leakage current is not needed to be accurately detected, and cost, occupied area and module loss can be reduced.

In some embodiments of the present application, in order to avoid the interference triggering error determination, the controller generates and outputs the second signal according to the first signal, and may specifically include: the controller generates and outputs the second signal when it is determined that the number of received first signals is greater than the second threshold for the first period of time. For example, the controller may generate and output the second signal when it receives the first signal 1 thousand times or more in 1 second.

In some embodiments of the present application, the controller outputting the second signal may specifically include: the controller may output a second signal to the power conversion circuit, where the second signal is used to control the power conversion circuit to stop operating, and stop the power conversion circuit to stop outputting the second signal to the second bus.

In some embodiments of the present application, a switch is disposed on the outer side of the power conversion circuit, and the switch may specifically use a relay to implement its function. The controller may also output a second signal to the switch, where the second signal is used to control the switch to be turned off, and cut off the connection between the bus and the power conversion circuit, so that the power conversion circuit stops outputting to the second bus. In particular, the power converter may include a first switch connected in series between the integrated inductor and the first bus bar, and a second switch connected in series between the integrated inductor and the second bus bar.

In some embodiments of the present application, when the integrated inductor is disposed at an input side of the power conversion circuit, that is, the integrated inductor is disposed at an input side of the first switch and the power conversion circuit, the controller may output a second signal to the first switch, where the second signal is used to control the first switch to be turned off. Further, the controller may output a second signal to the first switch and the power conversion circuit at the same time, where the second signal is used to control the power conversion circuit to stop operating and control the first switch to be turned off, and stop the power conversion circuit from outputting to the second bus by performing a shutdown process and an off process on the first switch.

In other embodiments of the present application, when the integrated inductor is disposed at the output end side of the power conversion circuit, that is, the integrated inductor is disposed at the output end of the second switch and the power conversion circuit, the controller may output a second signal to the second switch, where the second signal is used to control the second switch to be turned off. Further, the controller may output a second signal to the second switch and the power conversion circuit at the same time, where the second signal is used to control the power conversion circuit to stop operating and control the second switch to be turned off, and stop the power conversion circuit from outputting to the second bus by performing a shutdown process and an off process on the second switch.

The technical effects that any one of the second aspect and the third aspect may be designed to achieve are referred to the technical effects that any one of the foregoing first aspect may achieve, and the detailed description is not repeated here. These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

In order to more clearly describe the technical solutions in the embodiments or the background of the present application, the following description will describe the drawings that are required to be used in the embodiments or the background of the present application.

FIG. 1 is a schematic diagram of a conventional power converter;

FIG. 2 is a schematic diagram of a specific circuit of a prior art power converter;

fig. 3a is a schematic circuit diagram of a power converter according to an embodiment of the present disclosure;

fig. 3b is a schematic diagram of another circuit structure of the power converter according to the embodiment of the present application;

fig. 4 is a schematic circuit diagram of another circuit structure of the power converter according to the embodiment of the present application;

fig. 5 is a schematic circuit diagram of another circuit structure of the power converter according to the embodiment of the present application;

fig. 6 is a schematic diagram of another circuit structure of a power converter according to an embodiment of the present disclosure;

fig. 7 is a flowchart illustrating a control method of a power converter according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings.

The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include, for example, "one or more" such forms of expression, unless the context clearly indicates to the contrary.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

In addition, the same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present application are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present application. The drawings of the present application are merely schematic representations, not to scale.

Referring to fig. 1, in an energy storage scenario such as a communication battery, a data center energy storage battery, a vehicle-mounted power battery, and a photovoltaic energy storage battery, or a power supply circuit with a conversion function, a residual current detection circuit needs to be added to a power converter for leakage current protection, so that power failure caused by leakage is avoided. In addition, a filtering circuit for filtering the common mode component is generally arranged in the power converter so as to ensure the electromagnetic compatibility (electromagnetic compatibility, EMC) performance of the power converter. In fig. 1, the filter circuit includes an input filter circuit and an output filter circuit, and the residual current detection circuit is disposed at the output end side, wherein the input filter circuit is disposed between the input bus and the power conversion circuit, and the output filter circuit is disposed between the output bus and the power conversion circuit.

Referring to fig. 2, the residual flow detection circuit includes a detection inductor and a detection circuit connected to the detection inductor, and the detection circuit can determine the magnitude of leakage current flowing through the detection inductor by detecting a current signal induced by the detection inductor. The filter circuit includes a common-mode inductance having two coils (or windings) wound on the same core with the same number of turns and phase and wound in opposite directions. When normal current in the power converter flows through the common-mode inductor, the currents generate reverse magnetic fields in coils wound in the same phase to cancel each other, and the normal current is mainly influenced by the resistance of the coils; when common mode current flows through the coil, due to the isotropy of the common mode current, a magnetic field in the same direction is generated in the coil to increase the inductance of the coil, so that the coil presents high impedance, a stronger damping effect is generated, and the common mode current is attenuated to achieve the filtering effect.

Because the detection inductance and the common mode inductance are magnetic devices, the arrangement of a plurality of magnetic devices in the power converter increases the cost of the device, occupies a larger area of a circuit board, and increases the loss of a single board.

In order to overcome the problems, the application provides a power converter, a control method thereof and an energy storage system, wherein a common mode inductor for filtering and a detection inductor for residual current protection are integrated into the same inductor, so that the number of magnetic devices is reduced, the cost is saved, the circuit board area occupied by the magnetic devices is reduced, the single board loss is reduced, and the functions of common mode filtering and residual current protection are simultaneously realized by matching with corresponding circuits.

The power converter, the control method thereof and the energy storage system provided by the application are described in detail below with reference to the accompanying drawings.

Referring to fig. 3a and 3b, in an embodiment of the present application, a power converter includes: a power conversion circuit 11, an integrated inductor 12, a comparison circuit 13 and a controller 14. The input end of the power conversion circuit 11 is used for being connected with a first bus 21, and the first bus 21 can be connected with the output end of an energy storage device, a power supply or other circuits; the output of the power conversion circuit 11 is used to connect a second bus 22, the second bus 22 being connectable to a load device or a power grid. The power conversion circuit 11 is configured to output the electric energy provided by the first bus 21 to the second bus 22 after power conversion.

The power conversion circuit 11 includes a plurality of switching transistors, and the controller 14 is configured to control on-off states of the switching transistors in the power conversion circuit, so as to control an output voltage and an output current of the power conversion circuit, and further control an output efficiency and a conversion efficiency of the power conversion circuit. The switching transistors used in the power conversion circuit need to be selected from switching transistors capable of switching on/off states at high frequency, for example, the switching transistors can be selected from one or more of various types of switching transistors such as metal oxide semiconductor field effect transistors (metal oxide semiconductor field effect transistor, MOSFETs), bipolar junction transistors (bipolar junction transistor, BJTs), insulated gate bipolar transistors (insulated gate bipolar transistor, IGBTs), and the like, which are not listed here again in the embodiments of the present application. By way of example, the controller may be any one of a microprocessor (microcontroller unit, MCU), a general purpose central processing unit (central processing unit, CPU), a general purpose processor, digital signal processing (digital signal processing, DSP), application specific integrated circuit (application specific integrated circuits, ASIC), field programmable gate array (field programmable gate array, FPGA), etc., or may be any combination of one or more of other programmable logic devices, transistor logic devices, hardware components.

Referring to fig. 3a, the integrated inductor 12 may be connected in series between the input of the power conversion circuit 11 and the first bus bar 21, or, referring to fig. 3b, the integrated inductor 12 may also be connected in series between the output of the power conversion circuit 11 and the second bus bar 22. The integrated inductor 12 may specifically include a first winding f1, a second winding f2, and a third winding f3. The integrated inductor 12 is a magnetic device integrating common mode filtering and leakage current detection, wherein the first winding f1 and the second winding f2 form a common mode inductor and are used for common mode filtering, and the third winding f3 is connected with the comparison circuit 13 and is used for detecting leakage current. Specifically, the first winding f1, the second winding f2 and the third winding f3 may be wound on the same magnetic core, the number of turns and phases of the first winding f1 and the second winding f2 are the same, winding is reverse, and the number of turns of the third winding f3 is generally greater than that of the first winding f 1. When normal current flows through the integrated inductor 12, the currents generate opposite magnetic fields in the first winding f1 and the second winding f2 which are wound in the same phase to cancel each other, and at this time, the normal current is mainly influenced by the winding resistance; when common mode current flows through the first winding f1 and the second winding f2, due to the isotropy of the common mode current, a magnetic field in the same direction is generated in the first winding f1 and the second winding f2, so that the inductive reactance of the first winding f1 and the second winding f2 is increased, the first winding f1 and the second winding f2 are enabled to be high in impedance, a strong damping effect is generated, and the common mode current is attenuated, so that the filtering effect is achieved. The third winding f3 serves as a secondary winding of the integrated inductor 12, and generates an induced potential by the magnetic flux of the magnetic core, thereby generating an induced current proportional to the leakage current in the secondary circuit, i.e., the third winding f3. Under normal conditions, the common mode current is small, when leakage current occurs, the leakage current is output through the first winding f1 and the second winding f2, larger common mode current is generated, the third winding f3 of the integrated inductor 12 generates induced current signals according to the induced potential generated by the magnetic flux generated by the common mode current, and the induced potential generated by the third winding f3 is larger as the leakage current is larger.

In implementation, referring to fig. 3a, the first winding f1 and the second winding f2 may be connected to the first bus 21, where the integrated inductor 12 is used as input filter and the integrated inductor 12 uses the third winding f3 to detect whether the input terminal of the power conversion circuit 11 has a leakage current. Alternatively, referring to fig. 3b, the first winding f1 and the second winding f2 may be connected to the second bus 22, where the integrated inductor 12 is used as output filtering, and the integrated inductor 12 uses the third winding f3 to detect whether the output terminal of the power conversion circuit 11 has a leakage current.

Referring to fig. 3a and 3b, the comparison circuit 13 is connected to the controller 14, and the comparison circuit 13 can determine whether leakage current protection is required according to the induced current signal output from the third winding f3, and output a first signal to the controller 14 when it is determined that leakage current protection is required. The controller 14 generates and outputs a second signal after receiving the first signal, where the second signal is used to instruct the power conversion circuit 11 to stop outputting to the second bus 22, so as to complete the corresponding leakage current protection function.

In some embodiments of the present application, when the comparison circuit 13 determines that the voltage amplitude of the induced current signal is greater than the first threshold, and when it is determined that the leakage current abnormality needs to be leakage current protected, the comparison circuit 13 outputs a first signal to the controller 14, where the first signal may specifically be a high level signal. Accordingly, when the comparison circuit 13 determines that the voltage amplitude of the induced current signal is smaller than the first threshold value, the comparison circuit 13 may output a low level signal to the controller 14. The comparison circuit 13 only needs to judge whether leakage current protection is needed according to whether the induced current signal is larger than the first threshold value, and the leakage current is not needed to be accurately detected, so that the cost, the occupied area and the module loss can be reduced.

In some embodiments of the present application, to avoid an interference triggering false determination, the controller 14 may generate and output the second signal when it is determined that the number of received first signals is greater than the second threshold value within the first period of time. For example, the controller 14 may generate and output the second signal when it receives the first signal 1 thousand times or more in 1 second.

Referring to fig. 3a and 3b, in some embodiments of the present application, the controller 14 may perform a shutdown process on the power conversion circuit 11 to stop the output of the power conversion circuit 11 to the second bus 22 in a manner that outputs the second signal to the power conversion circuit 11, where the second signal is used to control the power conversion circuit 11 to stop operating.

Referring to fig. 4, in other embodiments of the present application, a switch K is connected to the outside of the power conversion circuit 11, and the switch K may specifically use a relay to perform its function. The controller 12 may also output a second signal to the switch K, the second signal being used to control the switch K to be turned off, and disconnect the bus from the power conversion circuit 11, so that the power conversion circuit 11 stops outputting to the second bus 22.

Referring to fig. 5 and 6, in particular, the power converter may include a first switch K1 connected to the first bus bar 21, and a second switch K2 connected to the second bus bar 22.

Referring to fig. 5, when the integrated inductor 12 is disposed at the input side of the power conversion circuit 11, that is, when the integrated inductor 12 is disposed at the first switch K1 and the input of the power conversion circuit 11, an output filter circuit may be disposed at the output of the power conversion circuit 11. The controller 14 may output a second signal to the first switch K1, the second signal being used to control the first switch K1 to be turned off. Further, the controller 14 may output a second signal to the first switch K1 and the power conversion circuit 11 at the same time, the second signal being used to control the power conversion circuit 11 to stop operating and to control the first switch K1 to be turned off, and stop the power conversion circuit 11 from outputting to the second bus 22 by performing a shutdown process to the power conversion circuit 11 and an off process to the first switch K1.

Referring to fig. 6, when the integrated inductor 12 is disposed at the output side of the power conversion circuit 11, that is, when the integrated inductor 12 is disposed at the output of the power conversion circuit 11 and the second switch K2, an input filter circuit may be disposed at the input of the power conversion circuit 11. The controller 14 may output a second signal to the second switch K2, the second signal being used to control the second switch K2 to be turned off. Further, the controller 14 may output a second signal to the second switch K2 and the power conversion circuit 11 at the same time, the second signal being used to control the power conversion circuit 11 to stop operating and to control the second switch K2 to be turned off, and stop the power conversion circuit 11 from outputting to the second bus 22 by performing a shutdown process to the power conversion circuit 11 and a turn-off process to the second switch K2.

In some embodiments of the present application, the power conversion circuit 11 may be specifically a direct current-to-direct current conversion circuit (DC-DC Converter, DCDC), where the DCDC is used to convert direct current provided by the energy storage device into different voltages for the subsequent devices through a boosting or step-down manner. Specifically, the DCDC can form a bidirectional BUCK/BOOST circuit by adopting an H-bridge topological structure, and supports bidirectional flow of charge and discharge energy and wide-range voltage regulation. The H-bridge topological structure specifically comprises an inductor, two bridge arms and two filter capacitors, wherein the two bridge arms and the two filter capacitors are respectively connected to two ends of the inductor, each bridge arm comprises two bridge arm switches connected in series, and each bridge arm is connected with one filter capacitor in parallel. Two ends of one bridge arm are respectively connected with the output end of the energy storage device, the middle point of the bridge arm is connected with one end of the inductor, and two ends of the other bridge arm are respectively connected with the direct current bus and the middle point of the bridge arm is connected with the other end of the inductor. DCDC may also employ a half-bridge LLC topology. Alternatively, DCDC may also employ a full bridge LLC topology.

In other embodiments of the present application, the power conversion circuit 11 may also be a dc-to-ac conversion circuit, and may be an energy storage converter (power conversion system, PCS) for converting dc power into ac power, which is responsible for ac power grid configuration. The PCS may specifically employ a full-bridge inverter topology.

In other embodiments of the present application, the power conversion circuit 11 may also be specifically an ac-to-dc conversion circuit, which is configured to convert ac power into dc power, and then may supply power to the load.

Based on the same inventive concept, the application also provides an energy storage system, which comprises an energy storage device and the power converter, wherein the energy storage device is connected with the power converter through a first bus, and the power converter is used for outputting electric energy provided by the energy storage device after power conversion. The power converter provided by the embodiment of the application can be widely applied to energy storage scenes such as a communication battery, a data center energy storage battery, a vehicle-mounted power battery, a photovoltaic energy storage battery and the like, and can also be applied to a power circuit with a power conversion function.

Based on the same inventive concept, the application also provides a control method of the power converter, wherein the power converter is the power converter with the structure provided by the embodiment of the application. Referring to fig. 7, the control method may specifically include the steps of:

s1, a comparison circuit outputs a first signal to a controller according to an induced current signal output by a third winding;

and S2, the controller generates and outputs a second signal according to the first signal, wherein the second signal is used for indicating the power conversion circuit to stop outputting to the second bus.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims

1. A power converter, comprising: the power conversion circuit, the integrated inductor, the comparison circuit and the controller;

the input end of the power conversion circuit is used for being connected with a first bus, the output end of the power conversion circuit is used for being connected with a second bus, and the power conversion circuit is used for outputting electric energy provided by the first bus to the second bus after power conversion;

the integrated inductor comprises a first winding, a second winding and a third winding, wherein the first winding and the second winding are connected with the first bus or the second bus, the first winding and the second winding form a common-mode inductance coil, and the third winding is connected with the comparison circuit;

the comparison circuit is connected with the controller and is used for outputting a first signal to the controller according to the induction current signal output by the third winding;

the controller is used for generating and outputting a second signal according to the first signal, and the second signal is used for indicating the power conversion circuit to stop outputting to the second bus.

2. The power converter of claim 1 wherein the comparison circuit is configured to output a first signal to the controller when the voltage magnitude of the induced current signal is greater than a first threshold.

3. A power converter as claimed in claim 1 or 2, wherein the controller is arranged to generate and output the second signal when it is determined that the number of received first signals is greater than a second threshold value within a first period of time.

4. A power converter as claimed in any one of claims 1 to 3, wherein the controller is arranged to output the second signal to the power conversion circuit, the second signal being arranged to control the power conversion circuit to cease operation.

5. The power converter of any of claims 1-4, further comprising a first switch and a second switch, the first switch in series with the first bus bar, the second switch in series with the second bus bar;

the integrated inductor is connected between the first switch and the input end of the power conversion circuit, or between the second switch and the output end of the power conversion circuit;

the controller is used for outputting the second signal to the first switch or the second switch, and the second signal is used for controlling the first switch or the second switch to be opened.

6. The power converter of any of claims 1-5 wherein the number of turns of said first winding is the same as the number of turns of said second winding and the number of turns of said third winding is greater than the number of turns of said first winding.

7. The power converter of any of claims 1-6, wherein the power conversion circuit is a dc-to-dc conversion circuit, the power converter further comprising an ac-to-dc conversion circuit;

the output end of the alternating current-to-direct current conversion circuit is connected with the input end of the direct current-to-direct current conversion circuit through the integrated inductor; or alternatively, the first and second heat exchangers may be,

the output end of the alternating current-direct current conversion circuit is connected with the input end of the direct current-direct current conversion circuit, and the output end of the direct current-direct current conversion circuit is connected with the integrated inductor.

8. An energy storage system, comprising: the power converter of any one of claims 1-6 and energy storage device, the energy storage device is connected with the power converter through a first bus, and the power converter is used for outputting the electric energy provided by the energy storage device after power conversion.

9. A control method of a power converter, characterized in that the power converter comprises a power conversion circuit, an integrated inductor, a comparison circuit and a controller; the input end of the power conversion circuit is used for being connected with a first bus, the output end of the power conversion circuit is used for being connected with a second bus, and the power conversion circuit is used for outputting electric energy provided by the first bus to the second bus after power conversion; the integrated inductor comprises a first winding, a second winding and a third winding, wherein the first winding and the second winding are connected with the first bus or the second bus, the first winding and the second winding form a common-mode inductance coil, and the third winding is connected with the comparison circuit; the control method comprises the following steps:

the comparison circuit outputs a first signal to the controller according to the induction current signal output by the third winding;

the controller generates and outputs a second signal according to the first signal, wherein the second signal is used for indicating the power conversion circuit to stop outputting to the second bus.

10. The control method of claim 9, wherein the comparing circuit outputs a first signal to the controller based on the induced current signal output from the third winding, comprising:

and the comparison circuit outputs a first signal to the controller when the voltage amplitude of the leakage current signal is larger than a first threshold value.

11. The control method according to claim 9 or 10, wherein the controller generates and outputs a second signal from the first signal, comprising:

the controller generates and outputs the second signal when it is determined that the number of the received first signals is greater than a second threshold value in a first period of time.

12. The control method according to any one of claims 9 to 11, wherein the controller outputting a second signal includes:

the controller outputs the second signal to the power conversion circuit, and the second signal is used for controlling the power conversion circuit to stop working.

13. The control method of any of claims 9-11, wherein the power converter further comprises a first switch and a second switch, the first switch being connected in series with the first bus bar, the second switch being connected in series with the second bus bar; the integrated inductor is connected between the first switch and the input end of the power conversion circuit, or between the second switch and the output end of the power conversion circuit;

the controller outputs a second signal comprising:

the controller outputs the second signal to the first switch or the second switch, and the second signal is used for controlling the first switch or the second switch to be turned off.