Battery wake-up system

Abstract

Disclosed in the present invention is a battery wake-up system. The battery wake-up system is arranged inside a converter, and the battery wake-up system comprises a battery unit and an inverter unit, wherein the inverter unit comprises a first bus capacitor module, a bidirectional isolation module, a second bus capacitor module, an inverter module and a relay module, which are sequentially connected in series; the relay module at least comprises a first branch circuit and a second branch circuit, which are connected in parallel; the first branch circuit comprises a soft-start resistor and a first relay, which are connected in series, and the second branch circuit comprises a second relay; the first relay is configured to close upon detecting that the voltage value of a grid is within a preset voltage range, so as to boost the voltage of the second bus capacitor module; and the second relay is configured to close upon completion of the boosting of the voltage of the second bus capacitor module, and after the second relay closes, the first relay opens. The battery wake-up system in the present invention achieves soft-starting of a bus capacitor and miniaturization of a converter, thereby reducing the cost.

Description

A battery wake-up system Technical Field

[0001] The present invention belongs to the field of converters, and in particular relates to a battery awakening system. Background Art

[0002] Inverters, such as integrated photovoltaic and storage devices, photovoltaic inverters, energy storage inverters or mobile energy storage devices, generally have inverter units and battery units inside them. Since the battery unit still has a certain amount of power consumption in the standby or undervoltage protection state, it will cause excessive discharge of the battery, affect the safety of the battery cell, and reduce the battery life. Therefore, the battery unit generally needs to have a standby sleep or undervoltage sleep function. After the battery unit is dormant, the inverter first needs to apply a certain voltage to the port of the battery unit to wake up the battery unit in order to work normally. However, existing inverters generally require an additional battery wake-up device to wake up the battery unit. The structure is relatively complex and the volume is large, which is not conducive to the miniaturization of the inverter and the cost is relatively high. Summary of the Invention

[0003] In response to the above technical problems, the present invention provides an improved battery wake-up system.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A battery wake-up system is provided inside a converter. The battery wake-up system comprises a battery unit and an inverter unit. The inverter unit is connected to the battery unit and the power grid respectively.

[0006] The inverter unit includes a first bus capacitor module, a bidirectional isolation module, a second bus capacitor module, an inverter module and a relay module connected in series in sequence, the first bus capacitor module is connected to the battery unit, and the relay module is connected to the power grid;

[0007] The relay module includes at least a first branch and a second branch arranged in parallel, the first branch includes a soft-start resistor and a first relay connected in series, and the second branch includes a second relay; the first relay is configured to close when it detects that the grid voltage value is within a preset voltage range, so that the voltage of the second bus capacitor module is raised; the second relay is configured to close after the second bus capacitor voltage is raised, and the first relay is disconnected after the second relay is closed.

[0008] Preferably, the bidirectional isolation module includes a DAB circuit, and the DAB circuit includes:

[0009] A primary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0010] A secondary full bridge comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series;

[0011] an isolation transformer, connected to the primary full bridge and the secondary full bridge respectively;

[0012] A DAB inductor is connected to the primary full bridge and the isolation transformer respectively.

[0013] Furthermore, the primary full bridge includes a first bridge arm and a second bridge arm connected in parallel, the first bridge arm includes a first switch module and a second switch module connected in series, and the second bridge arm includes a third switch module and a fourth switch module connected in series;

[0014] a secondary full bridge, comprising a third bridge arm and a fourth bridge arm connected in parallel, the third bridge arm comprising a fifth switch module and a sixth switch module connected in series, and the fourth bridge arm comprising a seventh switch module and an eighth switch module connected in series;

[0015] an isolation transformer, connected to the primary full bridge and the secondary full bridge, respectively, the isolation transformer comprising an isolation primary and an isolation secondary, one end of the isolation primary connected to a connection point between the third switch module and the fourth switch module, one end of the isolation secondary connected to a connection point between the fifth switch module and the sixth switch module, and the other end of the isolation secondary connected to a connection point between the seventh switch module and the eighth switch module;

[0016] A DAB inductor, one end of which is connected to the connection point between the first switch module and the second switch module, and the other end of which is connected to the other end of the isolation primary side.

[0017] Furthermore, the first switch module, the second switch module, the third switch module, the fourth switch module, the fifth switch module, the sixth switch module, the seventh switch module and the eighth switch module include diodes and power switches connected in parallel, and the power switches are insulated gate bipolar transistors or MOS tubes.

[0018] Preferably, the inverter module includes a first inverter bridge arm and a second inverter bridge arm connected in parallel, the first inverter bridge arm includes a ninth switch module and a tenth switch module connected in series, and the second inverter bridge arm includes an eleventh switch module and a twelfth switch module connected in series; the ninth switch module, the tenth switch module, the eleventh switch module and the twelfth switch module include diodes and power switches connected in parallel, and the power switch is an insulated gate bipolar transistor or a MOS tube.

[0019] Furthermore, the inverter unit further includes a filter module, and the filter module is connected in series between the inverter module and the relay module.

[0020] Furthermore, the filter module includes a filter inductor and a filter capacitor, one end of the filter inductor is connected to the connection point of the ninth switch module and the tenth switch module, and the other end of the filter inductor is connected to the relay module; one end of the filter capacitor is connected to the connection point of the filter inductor and the relay module, and the other end of the filter capacitor is connected to the connection point of the eleventh switch module and the twelfth switch module.

[0021] Preferably, the relay module further includes a voltage detection module, and the voltage detection module is electrically connected to the controller.

[0022] Preferably, the converter is a photovoltaic-storage integrated machine, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device.

[0023] Preferably, the first branch includes a first pre-charging branch and a second pre-charging branch connected in parallel; the first pre-charging branch includes a first soft-start resistor and a first pre-charging relay connected in series, and the second pre-charging branch includes a second soft-start resistor and a second pre-charging relay connected in series;

[0024] The second branch includes a first AC grid-connected branch and a second AC grid-connected branch connected in parallel; the first AC grid-connected branch includes a first AC grid-connected relay, and the second AC grid-connected branch includes a second AC grid-connected relay.

[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] The battery wake-up system of the present invention employs a relay module with a first branch and a second branch connected in parallel. The first branch includes a soft-start resistor and a first relay connected in series, while the second branch includes a second relay. To wake up a battery cell, the first relay is closed first. When the voltage of the second bus capacitor module rises to a preset voltage range, the second relay is closed and the first relay is opened, thereby soft-starting the bus capacitor and reducing the current impact on the bus capacitor. The battery wake-up system also has a simple structure and can be installed inside the converter, miniaturizing the converter and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] FIG1 is a connection diagram of a battery wake-up system according to an embodiment of the present invention;

[0029] Among them, 1. Battery unit; 2. Inverter unit; 3. Grid; 4. First bus capacitor module; 5. Bidirectional isolation module; 51. Primary full bridge; 52. Secondary full bridge; 6. Second bus capacitor module; 7. Inverter module; 8. Relay module; 9. Filter module; T dab , isolation transformer; L1, DAB inductor; C1, first bus capacitor; C2, second bus capacitor; T1, first switch module; T2, second switch module; T3, third switch module; T4, fourth switch module; T5, fifth switch module; T6, sixth switch module; T7, seventh switch module; T8, eighth switch module; T9, ninth switch module; T 10 , the tenth switch module; T 11 , the eleventh switch module; T 12 , the twelfth switch module; L2, filter inductor; C3, filter capacitor; R1, first pre-charging resistor; RY1, first pre-charging relay; R2, second pre-charging resistor; RY2, second pre-charging relay; RY3, first AC grid-connected relay; RY4, second AC grid-connected relay. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings to make the advantages and features of the present invention more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0031] As shown in Figure 1, this embodiment discloses a battery wake-up system, which is arranged inside the converter. The converter can be a photovoltaic storage integrated machine, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device, which is not limited here. Among them, the battery wake-up system includes a battery unit 1 and an inverter unit 2, and the inverter unit 2 is connected to the battery unit 1 and the power grid 3 respectively. The inverter unit 2 includes a first bus capacitor module 4, a bidirectional isolation module 5, a second bus capacitor module 6, an inverter module 7 and a relay module 8 connected in series in sequence. The first bus capacitor module 4 is connected to the battery unit 1, and the relay module 8 is connected to the power grid 3. Among them, the first bus capacitor module 4 includes a first bus capacitor C1, and the second bus capacitor module 6 includes a second bus capacitor C2. Specifically in this embodiment, C1 is a low-voltage side bus capacitor, and C2 is a high-voltage side bus capacitor.

[0032] The relay module 8 includes at least a first branch and a second branch connected in parallel. The first branch includes a soft-start resistor and a first relay connected in series. The second branch includes a second relay. The relay module 8 also includes a controller (not shown) electrically connected to the first and second relays to control the opening and closing of the first and second relays.

[0033] Specifically, as shown in Figure 1, the first branch in this embodiment includes a first pre-charging branch and a second pre-charging branch connected in parallel. The first pre-charging branch includes a first soft-start resistor R1 and a first pre-charging relay RY1 connected in series, and the second pre-charging branch includes a second soft-start resistor R2 and a second pre-charging relay RY2 connected in series. The second branch includes a first AC grid-connected branch and a second AC grid-connected branch connected in parallel. The first AC grid-connected branch includes a first AC grid-connected relay RY3, and the second AC grid-connected branch includes a second AC grid-connected relay RY4. It should be noted that in some other embodiments, the number of pre-charging resistors, pre-charging relays and AC grid-connected relays can be one or more, and the specific number is not limited here.

[0034] The bidirectional isolation module 5 specifically includes a dual active bridge (DAB) circuit, which includes a primary full bridge 51, a secondary full bridge 52, an isolation transformer T dab And DAB inductor L1. Isolation transformer T dab The DAB inductor L1 is connected to the primary full bridge 51 and the secondary full bridge 52 respectively. dab Specifically, the primary full bridge 51 includes a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first switch module T1 and a second switch module T2 connected in series, and the second bridge arm includes a third switch module T3 and a fourth switch module T4 connected in series. The secondary full bridge 52 includes a third bridge arm and a fourth bridge arm connected in parallel. The third bridge arm includes a fifth switch module T5 and a sixth switch module T6 connected in series, and the fourth bridge arm includes a seventh switch module T7 and an eighth switch module T8 connected in series. The isolation transformer T dabThe device comprises an isolated primary and an isolated secondary. One end of the isolated primary is connected to the connection point between the third switch module T3 and the fourth switch module T4. One end of the isolated secondary is connected to the connection point between the fifth switch module T5 and the sixth switch module T6. The other end of the isolated secondary is connected to the connection point between the seventh switch module T7 and the eighth switch module T8. The first switch module T1, the second switch module T2, the third switch module T3, the fourth switch module T4, the fifth switch module T5, the sixth switch module T6, the seventh switch module T7, and the eighth switch module T8 include diodes and power switches connected in parallel. The power switches are insulated gate bipolar transistors (MOS transistors). One end of a DAB inductor L1 is connected to the connection point between the first switch module T1 and the second switch module T2, and the other end of the DAB inductor L1 is connected to the other end of the isolated primary.

[0035] The inverter module 7 includes a first inverter bridge arm and a second inverter bridge arm connected in parallel. The first inverter bridge arm includes a ninth switch module T9 and a tenth switch module T1 connected in series. 10 The second inverter bridge arm includes an eleventh switch module T connected in series. 11 and the twelfth switch module T 12 Among them, the ninth switch module T9 and the tenth switch module T 10 , Eleventh switch module T 11 and the twelfth switch module T 12 It includes a diode and a power switch connected in parallel with each other. The power switch is an insulated gate bipolar transistor or a MOS tube.

[0036] The battery wake-up system also includes a filter module 9. The filter module 9 is connected in series between the inverter module 7 and the relay module 8. The filter module 9 includes a filter inductor L2 and a filter capacitor C3. One end of the filter inductor L2 is connected to the ninth switch module T9 and the tenth switch module T 10 The other end of the filter inductor L2 is connected to the grid 3. One end of the filter capacitor C3 is connected to the connection point of the filter inductor L2 and the grid 3, and the other end of the filter capacitor C3 is connected to the eleventh switch module T 11 and the twelfth switch module T 12 connection point.

[0037] Furthermore, the battery wake-up system can also include a voltage detection module, which includes a grid voltage sampling unit for detecting the voltages on both sides of the grid, and a bus voltage sampling unit for collecting the bus voltage. The grid voltage sampling unit and the bus voltage sampling unit are electrically connected to the controller respectively.

[0038] The specific process of the battery wake-up system in this embodiment is described in detail below:

[0039] Battery wake-up includes power-on wake-up and remote wake-up. Power-on wake-up means that if no CAN communication is detected within 30 seconds after the converter is powered on by AC, it will enter battery wake-up mode. Users can also remotely wake up the battery through the app.

[0040] Power-on wake-up includes the following steps:

[0041] The voltage detection module detects the AC grid voltage. If the voltage detection module detects that the voltage on both sides of the grid 3 is greater than the preset grid voltage range value (safety parameter value), for example, 230*0.8V, the first pre-charging relay RY1 and the second pre-charging relay RY2 are closed. 10 , Eleventh switch module T 11 and the twelfth switch module T 12 Maintain the disconnected state. The grid voltage charges the second bus capacitor C2 through the first pre-charging relay RY1, the second pre-charging relay RY2, the first soft-start resistor R1, the second soft-start resistor R2, and the anti-parallel diode built into the inverter module 7, raising the high-voltage side bus capacitor voltage through uncontrolled rectification.

[0042] When the voltage of the second bus capacitor module 6 rises to a certain stage, for example, the bus voltage is greater than Vgrid*1.414-20V (the effective value of the grid voltage multiplied by the square root of 2 minus 20V, for example 310V), the first AC grid-connected relay RY3 and the second AC grid-connected relay RY4 are closed, and the first pre-charging relay RY1 and the second pre-charging relay RY2 are disconnected. This method can effectively reduce the impact of the grid voltage on the second bus capacitor module 6.

[0043] When the voltage of the second busbar capacitor module 6 stabilizes, T1-T4 are all low (the switch module is disconnected), and only the high-voltage side of T5-T8 is turned on, with a 50% duty cycle. Open-loop control is implemented using the internal phase shift angle (the delay in turning on T7 relative to T5 accounts for the entire cycle). The internal phase shift angle gradually increases from 0 to a maximum of 0.5. Through the transformer, DAB inductor, and anti-parallel diode on the low-voltage side, the voltage of the first busbar capacitor C1 of the first busbar capacitor module 4 is raised to a certain value, for example, below 60V, and can be 48V (lower than the voltage that can wake up the battery), achieving a slow start of the low-voltage bus voltage.

[0044] After the low-voltage bus completes its slow start, the DAB's single phase shift (SPS) control is used, and the PI controller outputs the outer phase shift angle. The outer loop control target is the voltage of the first bus capacitor C1, and the inner loop is the current of the DAB inductor L1, achieving a slow increase in the first bus capacitor C1. If the controller detects a communication connection with the battery, it means that the battery has been woken up successfully.

[0045] In summary, the battery wake-up system in this embodiment has the following advantages:

[0046] 1. By setting a first branch and a second branch in parallel in the relay module, the first branch includes a soft-start resistor and a first relay connected in series, and the second branch is provided with a second relay. When the battery unit is awakened, the first relay is closed first. When the voltage of the second bus capacitor module rises to a preset voltage range, the second relay is closed and the first relay is disconnected. That is, the soft-start relay and the soft-start resistor are used to achieve soft start of the bus capacitor, thereby reducing the current impact on the bus capacitor.

[0047] 2. The battery wake-up system has a simple structure and can be installed inside the converter, which enables the converter to be miniaturized and reduces costs.

[0048] 3. Utilize the bidirectional energy flow characteristics of the DAB circuit to achieve the step-down conversion output of the high-voltage bus capacitor to the low-voltage bus capacitor. After the battery unit detects the low-voltage bus voltage, the battery is awakened.

[0049] 4. The high-voltage side bus capacitor voltage is raised by uncontrolled rectification, and the low-voltage side bus voltage is slowly started and raised by combining open-loop control and outer-loop control. This can effectively avoid unidirectional magnetic saturation and uncontrolled battery charging and discharging, prevent DAB circuit overcurrent, and achieve a slow voltage increase.

[0050] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0051] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. Furthermore, terms such as "upper," "lower," "left," and "right" used in this disclosure are intended solely to describe the relative positions of the components of the disclosure as shown in the accompanying drawings.

[0052] The above embodiment is intended only to illustrate the technical concepts and features of the present invention and is a preferred embodiment. Its purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. It is not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the principles of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A battery awakening system, which is arranged inside a converter, the battery awakening system comprises a battery unit and an inverter unit, the inverter unit is connected to the battery unit and a power grid respectively, It is characterized in that The inverter unit comprises a first bus capacitor module, a bidirectional isolation module, a second bus capacitor module, an inverter module and a relay module which are connected in series in sequence, the first bus capacitor module is connected to the battery unit, and the relay module is connected to the power grid; The relay module at least includes a first branch and a second branch connected in parallel, the first branch includes a soft-start resistor and a first relay connected in series, and the second branch includes a second relay; the first relay is configured to close when detecting that the grid voltage value is within a preset voltage range, so that the voltage of the second bus capacitor module is raised; The second relay is configured to close after the second bus capacitor voltage is raised, and the first relay is opened after the second relay is closed.

2. The battery wake-up system according to claim 1, characterized in that: The bidirectional isolation module includes a DAB circuit, and the DAB circuit includes: A primary full bridge, comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series; A secondary full bridge, comprising at least two bridge arms connected in parallel, each of the bridge arms comprising at least two switch modules connected in series; an isolation transformer, connected to the primary full bridge and the secondary full bridge respectively; The DAB inductor is connected to the primary full bridge and the isolation transformer respectively.

3. The battery wake-up system according to claim 2, characterized in that: The primary full bridge comprises a first bridge arm and a second bridge arm connected in parallel, the first bridge arm comprises a first switch module and a second switch module connected in series, and the second bridge arm comprises a third switch module and a fourth switch module connected in series; A secondary full bridge, comprising a third bridge arm and a fourth bridge arm connected in parallel, wherein the third bridge arm comprises a fifth switch module and a sixth switch module connected in series, and the fourth bridge arm comprises a seventh switch module and an eighth switch module connected in series; an isolation transformer, which is connected to the primary full bridge and the secondary full bridge respectively, the isolation transformer comprising an isolation primary and an isolation secondary, one end of the isolation primary is connected to a connection point between the third switch module and the fourth switch module, one end of the isolation secondary is connected to a connection point between the fifth switch module and the sixth switch module, and the other end of the isolation secondary is connected to a connection point between the seventh switch module and the eighth switch module; A DAB inductor, one end of which is connected to a connection point between the first switch module and the second switch module, and the other end of which is connected to the other end of the isolation primary side.

4. The battery wake-up system according to claim 3, characterized in that: The first switch module, the second switch module, the third switch module, the fourth switch module, the fifth switch module, the sixth switch module, the seventh switch module and the eighth switch module include diodes and power switches connected in parallel with each other, and the power switch is an insulated gate bipolar transistor or a MOS tube.

5. The battery wake-up system according to claim 1, characterized in that: The inverter module includes a first inverter bridge arm and a second inverter bridge arm connected in parallel, the first inverter bridge arm includes a ninth switch module and a tenth switch module connected in series, and the second inverter bridge arm includes an eleventh switch module and a twelfth switch module connected in series; the ninth switch module, the tenth switch module, the eleventh switch module and the twelfth switch module include diodes and power switches connected in parallel, and the power switch is an insulated gate bipolar transistor or a MOS tube.

6. The battery wake-up system according to claim 5, characterized in that: The inverter unit further includes a filter module, and the filter module is connected in series between the inverter module and the relay module.

7. The battery wake-up system according to claim 6, characterized in that: The filter module includes a filter inductor and a filter capacitor, one end of the filter inductor is connected to the connection point of the ninth switch module and the tenth switch module, and the other end of the filter inductor is connected to the relay module; one end of the filter capacitor is connected to the connection point of the filter inductor and the relay module, and the other end of the filter capacitor is connected to the connection point of the eleventh switch module and the twelfth switch module.

8. The battery wake-up system according to claim 1, characterized in that: The relay module further comprises a voltage detection module, and the voltage detection module is electrically connected to the controller.

9. The battery wake-up system according to claim 1, characterized in that: The converter is a photovoltaic and energy storage integrated machine, a photovoltaic inverter, an energy storage inverter or a mobile energy storage device.

10. The battery wake-up system according to claim 1, characterized in that: The first branch includes a first pre-charging branch and a second pre-charging branch connected in parallel; the first pre-charging branch includes a first soft-start resistor and a first pre-charging relay connected in series, and the second pre-charging branch includes a second soft-start resistor and a second pre-charging relay connected in series; The second branch includes a first AC grid-connected branch and a second AC grid-connected branch connected in parallel; the first AC grid-connected branch includes a first AC grid-connected relay, and the second AC grid-connected branch includes a second AC grid-connected relay.

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