A charging control circuit and energy storage system

Abstract

The present invention relates to the technical field of energy storage power supply, and mainly provides a charging control circuit and an energy storage system. The circuit includes a voltage conversion module, a mains connection terminal connected to the high-voltage side of the voltage conversion module, a switching module and a detection module respectively connected to the transformer of the voltage conversion module, and a sampling module connected to the switching module. The low-voltage side of the voltage conversion module is connected to the battery, the switching module is connected to the detection module, and the sampling module is connected to the battery. The sampling module is used to control the switching module to switch the transformer to a first connection state when the collected battery voltage is less than a first preset value, so as to increase the turns ratio of the transformer, so that the mains power can charge the battery normally. The detection module will control the switching module to switch the transformer to a second connection state when the voltage on the high-voltage side is greater than a second preset value, so as to avoid waste of resources during charging due to an excessively large turns ratio, wherein the turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage power supplies, and in particular to a charging control circuit and an energy storage system. Background Art

[0002] In the era of vigorous development of new energy, energy storage power supplies have been widely used as emerging energy products. However, the diversification and popularization of its application scenarios have also brought many problems. Since users may exhaust the SOC (State of Charge) of the energy storage power supply to 0% and not charge it for a long time, coupled with the self-consumption of the BMS (Battery Management System), the battery pack is prone to enter the feeding state, and small-capacity micro-storage power supplies are particularly prone to this situation. Once the battery pack voltage is lower than the feeding threshold, the battery pack will be scrapped and cannot be used.

[0003] In addition, when charging the battery pack through the mains, the battery pack is required to output a voltage of the same amplitude as the mains to achieve phase lock and then charge, but the battery pack in the feeding state cannot meet this voltage requirement, resulting in the mains being unable to charge it. Therefore, in order to ensure that the battery pack can be charged normally in the feeding state, it is necessary to provide a charging control circuit. Summary of the invention

[0004] The embodiments of the present invention mainly provide a charging control circuit and an energy storage system, which are intended to solve the technical problem in the prior art that the battery pack cannot be charged by the mains when the battery pack is fed with power.

[0005] In order to solve the above technical problems, a technical solution adopted by the embodiment of the present invention is: providing a charging control circuit, the charging control circuit comprising a sampling module, a voltage conversion module, a switching module, a mains connection terminal and a detection module;

[0006] The low voltage side of the voltage conversion module is connected to the battery, the high voltage side of the voltage conversion module is respectively connected to the detection module and the mains connection end, the transformer of the voltage conversion module is connected to the switching module, the switching module is respectively connected to the sampling module and the detection module, and the sampling module is also used to connect to the battery;

[0007] The sampling module is used to collect the battery voltage, and when the battery voltage is less than a first preset value, output a control signal to the switching module so that the switching module controls the transformer to switch to the first connection state;

[0008] The detection module is used to output a locking signal to the switching module when the voltage of the bus capacitor on the high-voltage side is greater than a second preset value, so that the switching module controls the transformer to switch to a second connection state, wherein the transformer turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state;

[0009] Wherein, the sampling module includes a battery voltage sampling unit, a mains voltage sampling unit and a logic control unit;

[0010] The battery voltage sampling unit is connected to the battery and the logic control unit respectively, the mains voltage sampling unit is connected to the mains connection terminal and the logic control unit respectively, and the logic control unit is connected to the switching module;

[0011] The battery voltage sampling unit is used to collect the battery voltage of the battery to determine whether the battery voltage is less than a first preset value and greater than a third preset value, and output a feeding signal when the battery voltage is less than the first preset value and greater than the third preset value, wherein the first preset value is greater than the third preset value;

[0012] The mains voltage sampling unit is used to collect the mains voltage of the mains connection end to determine whether the mains voltage is within a preset range, and output a power supply signal when the mains voltage of the mains connection end is within the preset range;

[0013] The logic control unit is used to output a control signal to the switching module when receiving the feeding signal and the power supply signal.

[0014] Optionally, the sampling module is also connected to the mains connection terminal, and is used to collect the voltage of the mains connection terminal, and output a control signal when the voltage of the mains connection terminal is within a preset range and the battery voltage is less than a first preset value.

[0015] Optionally, the battery voltage sampling unit includes a comparator U1, a comparator U2 and an AND gate U5;

[0016] The positive input terminal of the comparator U1 is used to receive the battery voltage, the reverse input terminal of the comparator U1 is connected to the third preset value, the positive input terminal of the comparator U2 is connected to the first preset value, the reverse input terminal of the comparator U2 is used to receive the battery voltage, the output terminal of the comparator U1 and the output terminal of the comparator U2 are both connected to the input terminal of the AND gate U5, and the output terminal of the AND gate U5 is connected to the logic control unit.

[0017] Optionally, the mains voltage sampling unit includes a comparator U3, a comparator U4 and an AND gate U6;

[0018] The logic control unit includes an AND gate U7;

[0019] The positive input terminal of the comparator U3 is used to receive the voltage of the mains connection terminal, the reverse input terminal of the comparator U3 is connected to the fourth preset value, the positive input terminal of the comparator U4 is connected to the fifth preset value, the reverse input terminal of the comparator U4 is used to receive the voltage of the mains connection terminal, the output terminal of the comparator U3 and the output terminal of the comparator U4 are both connected to the input terminal of the AND gate U6, the output terminal of the AND gate U6 is connected to the input terminal of the AND gate U7, the input terminal of the AND gate U7 is also connected to the output terminal of the AND gate U5, and the output terminal of the AND gate U7 is connected to the switching module, wherein the fourth preset value is less than the fifth preset value.

[0020] Optionally, the primary side of the transformer is provided with a winding N1, and the secondary side of the transformer is provided with a winding N2 and a winding N3 connected in series with each other;

[0021] The switching module includes a relay RLY1 and a control unit;

[0022] The connection end of the contact group of the relay RLY1 is connected to the winding N2 or the winding N3 respectively, the common end of the contact group of the relay RLY1 is connected to the high voltage side of the voltage conversion module, the coil end of the relay RLY1 is connected to the control unit, and the control unit is also connected to the sampling module and the detection module respectively;

[0023] The control unit is used to receive the control signal output by the sampling module, and switch the connection end of the contact group of the relay RLY1 to be connected to the winding N3 based on the control signal; and

[0024] A locking signal output by the detection module is received, and the connection end of the contact group of the relay RLY1 is switched to be connected to the winding N2 according to the locking signal.

[0025] Optionally, the control unit includes a switch tube Q21, a resistor R1 and a resistor R2;

[0026] The control end of the switch tube Q21 is connected to the sampling module and the detection module respectively through the resistor R2, the first end of the switch tube Q21 is connected to the coil end of the relay RLY1 through the resistor R1, and the second end of the switch tube Q21 is used for grounding.

[0027] Optionally, the detection module includes an optical coupling isolation unit and a detection unit;

[0028] The detection unit is connected to the bus capacitor and the optical coupling isolation unit respectively, and the optical coupling isolation unit is connected to the switching module;

[0029] The detection unit is used to detect the voltage of the bus capacitor, and when the voltage of the bus capacitor is greater than the second preset value, output a first driving signal to the optical coupling isolation unit;

[0030] The optical coupling isolation unit is used to output a locking signal to the switching module when receiving the first driving signal.

[0031] Optionally, the detection unit includes a resistor R7, a resistor R10 and a voltage regulator tube ZD1;

[0032] The resistor R7 is connected to the bus capacitor and the resistor R10 respectively. The resistor R7 is also connected to the cathode of the voltage regulator tube ZD1. The anode of the voltage regulator tube ZD1 is connected to the optical coupling isolation unit. The resistor R10 is also used for grounding.

[0033] Optionally, the charging control circuit further includes a grid-connected relay and a control module for controlling the operation of the grid-connected relay, and the voltage conversion module is also connected to the mains connection terminal through the grid-connected relay;

[0034] The control module is used for delaying a preset time to output a grid-connected signal to control the grid-connected relay to be attracted when the voltage of the bus capacitor is greater than the second preset value.

[0035] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present invention is: to provide an energy storage system, the energy storage system comprising:

[0036] Battery;

[0037] conversion circuit; and

[0038] The charging control circuit as described above, wherein the charging control circuit is connected to the battery and the conversion circuit respectively.

[0039] Different from the related art, the present invention provides a charging control circuit and energy storage system, wherein the charging control circuit includes a sampling module, a voltage conversion module, a switching module, a mains connection terminal and a detection module; the low voltage side of the voltage conversion module is connected to the battery, the high voltage side of the voltage conversion module is connected to the mains connection terminal, the transformer of the voltage conversion module is connected to the switching module and the detection module respectively, the switching module is connected to the sampling module and the detection module respectively, and the sampling module is also used to connect to the battery. The sampling module is used to collect the battery voltage, and when the battery voltage is less than a first preset value, the switching module controls the switching module to switch the transformer to a first connection state, so as to increase the turns ratio of the transformer, thereby increasing the amplitude of the output voltage of the voltage conversion module, so that the output voltage of the voltage conversion module meets the requirements, and the mains can charge the battery normally. After the amplitude of the output voltage of the voltage conversion module is increased, the detection module will output a locking signal to the switching module when the voltage of the high-voltage side bus capacitor is greater than a second preset value, so that the switching module controls the transformer to switch to the second connection state, thereby changing the turns ratio of the transformer to the original turns ratio, thereby avoiding resource waste caused by an excessively large transformer turns ratio during mains charging. The transformer turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0041] Figure 1 This is an application scenario of an energy storage system provided by an embodiment of the present invention;

[0042] Figure 2 is a structural block diagram of a charging control circuit provided by an embodiment of the present invention;

[0043] Figure 3 is a circuit diagram of a charging control circuit provided by an embodiment of the present invention;

[0044] Figure 4 is a circuit diagram of a charging control circuit provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present invention. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order from the module division in the device schematic diagram or the order in the flow chart.

[0047] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0048] See also Figure 1 , Figure 1 This is an application scenario of an energy storage system provided by an embodiment of the present invention, such as Figure 1 As shown, the application scenario 1000 includes an energy storage system 1 and a mains 2, wherein the energy storage system 1 is used to be connected to the mains 2. The mains 2 refers to the alternating current supplied by the power supply department in daily life. When the energy storage system 1 is connected to the mains 2, the mains 2 is used to charge the energy storage system 1.

[0049] Further, such as Figure 1 As shown, the energy storage system 1 includes a battery 100, a conversion circuit 200 and a charging control circuit 300; the charging control circuit 300 is connected to the battery 100 and the conversion circuit 200 respectively, and the conversion circuit 200 is also connected to the mains 2. When the mains 2 charges the energy storage system 1, the conversion circuit 200 receives the alternating current output by the mains 2, and converts the alternating current into direct current and then inputs it into the charging control circuit 300, so as to charge the battery 100 through the charging control circuit 300.

[0050] It should be noted that in the process of charging the energy storage system 1 through the mains 2, a phase-locked operation is required, that is, the voltage of the energy storage system 1 needs to be consistent with the voltage amplitude, frequency and phase angle of the mains 2 to avoid the formation of an inappropriate potential difference in the charging circuit to damage the energy storage system 1, wherein the frequency and phase angle can be conventionally adjusted and matched by the controller, and the voltage amplitude of the energy storage system 1 is related to the battery voltage, so this application mainly describes in detail the voltage amplitude adjustment output by the energy storage system 1. However, when the energy storage system 1 has not been charged for a long time, the battery 100 in the energy storage system 1 will be in a feeding state. At this time, the voltage output by the battery 100 through the conversion circuit 200 is not the same as the output voltage amplitude of the mains 2, so the mains 2 cannot charge the energy storage system 1. Based on this, the present application introduces the charging control circuit 300. When the energy storage system 1 needs to be charged, the output voltage of the energy storage system 1 is adjusted by the charging control circuit 300, so that the output voltage of the energy storage system 1 is the same as the output voltage amplitude of the mains 2. When the output voltage of the energy storage system 1 is the same as the output voltage amplitude of the mains 2, the mains 2 completes phase locking and starts to charge the energy storage system 1.

[0051] It can be known that the AC power output by the mains 2 is generally in the form of a sine wave, and the peak value of the sine wave is 1.414 times the effective value. Therefore, before the mains 2 charges the energy storage system 1, the output voltage of the charging control circuit 300 needs to be higher than 1.414 times the output voltage of the mains 2. At this time, the output voltage of the charging control circuit 300 after transformation by the conversion module 200 is the same as the output voltage amplitude of the mains 2, that is, when the output voltage of the charging control circuit 300 is higher than the output voltage of the mains 1.414 times, the output voltage of the charging control circuit 300 matches the output voltage of the mains 2, and the output voltage of the energy storage system 1 is the same as the output voltage amplitude of the mains 2, and a phase-locked action is performed, wherein the phase and frequency of the output voltage are the same as the frequency and phase of the mains voltage. Adjustment belongs to conventional technical means, and this embodiment will not be repeated.

[0052] In some embodiments, the conversion circuit 200 may be a bridgeless PFC circuit or an inverter circuit. Specifically, when charging the battery 100 in the energy storage system 1, the battery 100 first outputs a voltage to the charging control circuit 300 so that the charging control circuit 300 adjusts the magnitude of the output voltage. Since the voltage stored in the battery 100 is direct current, and the voltage of the mains 2 is alternating current, when the charging control circuit 300 inputs the adjusted output voltage to the conversion circuit 200, the conversion circuit 200 converts the direct current into alternating current. At this time, the conversion circuit 200 is an inverter circuit. When the mains 2 starts to charge the battery 100 in the energy storage system 1, the conversion circuit 200 is a bridgeless PFC circuit to convert the alternating current passing through the bridgeless PFC circuit into direct current and input it into the energy storage system 1. That is, when the energy storage system 1 outputs voltage, the conversion circuit 200 is an inverter circuit, and when the energy storage system 1 receives voltage, the conversion circuit 200 is a bridgeless PFC circuit.

[0053] In some embodiments, see Figure 2 , Figure 2 is a structural block diagram of a charging control circuit provided by an embodiment of the present invention, such as Figure 2 As shown, the charging control circuit 300 includes a sampling module 31, a voltage conversion module 32, a switching module 33, a mains connection terminal 34 and a detection module 35;

[0054] The low voltage side of the voltage conversion module 32 is connected to the battery 100, and the high voltage side of the voltage conversion module 32 is respectively connected to the mains connection terminal 34 and the detection module 35, the transformer T1 of the voltage conversion module 32 is connected to the switching module 33, and the switching module 33 is respectively connected to the sampling module 31, and the sampling module 31 is also used to connect to the battery 100;

[0055] The sampling module 31 is used to collect the battery voltage, and when the battery voltage is less than a first preset value, outputs a control signal to the switching module 33, so that the switching module 33 controls the transformer T1 to switch to the first connection state;

[0056] The detection module 35 is used to output a locking signal to the switching module 33 when the voltage of the bus capacitor EC1 on the high-voltage side is greater than a second preset value, so that the switching module 33 controls the transformer T1 to switch to a second connection state, wherein the transformer turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state.

[0057] Specifically, the sampling module 31 is used to collect the battery voltage of the battery 100 and determine whether the voltage of the battery 100 is in a feeding state, that is, whether the battery voltage is less than a first preset value. When the battery voltage is less than the first preset value, it is considered that the battery 100 is in a feeding state. At this time, the switching module 33 receives the control signal output by the sampling module 31, and switches the transformer T1 in the voltage conversion module 32 to a first connection state based on the control signal to change the turns ratio of the transformer T1, thereby increasing the output voltage of the transformer T1, and further increasing the voltage input to the bus capacitor EC1. Among them, the transformer T1 is connected to the bus capacitor EC1, and the bus capacitor EC1 is connected to the conversion circuit 200. When the transformer T1 outputs voltage to the bus capacitor EC1, the detection module 35 will detect the voltage on the bus capacitor EC1 in real time. When the voltage of the bus capacitor EC1 is greater than the second preset value, it means that the voltage on the bus capacitor EC1 matches the output voltage of the mains 2, and the voltage output by the conversion circuit 200 is the same as the output voltage amplitude of the mains 2. When the voltage of the bus capacitor EC1 is greater than the second preset value, the detection module 35 will output a locking signal to the switching module 33, so that the switching module 33 controls the transformer T1 to switch to the second connection state, thereby restoring the original turns ratio of the transformer T1. When the voltage output by the conversion circuit 200 is the same as the output voltage amplitude of the mains 2, the mains connection terminal 34 starts to receive the voltage output by the mains 2, so as to charge the battery 100 through the conversion circuit 200 and the voltage conversion module 32.

[0058] It should be noted that the transformer turns ratio refers to the winding ratio between the primary and secondary sides of the transformer. When the voltage output by the battery 100 through the voltage conversion module 32 does not match the output voltage of the mains 2, the turns ratio between the primary and secondary sides of the transformer T1 in the voltage conversion module 32 is increased, thereby increasing the voltage ratio between the primary and secondary sides, thereby increasing the output voltage of the voltage conversion module 32. When the voltage on the bus capacitor EC1 is greater than the second preset value, the mains 2 starts to charge the energy storage system 1; at this time, the transformer T1 is switched to the original turns ratio to prevent the high-power charging current from damaging the transformer T1.

[0059] In some embodiments, the sampling module 31 is also connected to the mains connection terminal 34, and is used to collect the voltage of the mains connection terminal 34, and output a control signal when the voltage of the mains connection terminal 34 is within a preset range and the battery voltage is less than a first preset value.

[0060] Specifically, when the voltage of the mains connection terminal 34 is within a preset range, it is considered that the voltage output by the mains 2 can normally charge the energy storage system 1. At this time, if the voltage on the bus capacitor EC1 matches the output voltage of the mains 2, the mains 2 is successfully phase-locked, thereby charging the energy storage system 1. If the voltage of the mains connection terminal 34 is not within the preset range, the mains 2 does not meet the charging requirements of the energy storage system 1. At this time, even if the voltage on the bus capacitor EC1 matches the output voltage of the mains 2, the mains 2 will not charge the energy storage system 1.

[0061] In some embodiments, see Figure 3 , Figure 3 is a circuit diagram of a charging control circuit provided by an embodiment of the present invention, such as Figure 3 As shown, the voltage conversion module 32 includes a transformer T1, a bus capacitor EC1, a resonant inductor L3, a resonant capacitor C3, power tubes Q13, Q14, Q17 and Q18 constituting a first bridge unit, and power tubes Q15, Q16, Q19 and Q20 constituting a second bridge unit;

[0062] The primary side of the transformer T1 is provided with a winding N1, and the secondary side of the transformer T1 is provided with windings N2 and N3 connected in series, the same-name ends of the windings N2 and N3 are in the same position, and the number of turns of the windings N2 and N3 is greater than the number of turns of the winding N1. The primary side of the transformer T1 is connected to the first bridge unit, and the first bridge unit is also connected to the battery 100. The same-name end of the winding N2 of the transformer T1 is connected to the second bridge unit through the resonant inductor L3, and the winding N3 of the transformer T1 is connected to the resonant capacitor C3 through the switching module 33. The resonant capacitor C3 is also connected to the second bridge unit, and the second bridge unit is also connected to the bus capacitor EC1, and the bus capacitor EC1 is respectively connected to the conversion circuit 200 and the detection module 35.

[0063] It can be known that the primary-to-secondary turns ratio of the transformer T1 is equal to the primary-to-secondary voltage ratio, so different voltage conversions can be achieved by changing the turns ratio of the transformer T1. When the output voltage of the battery 100 is input to the primary side of the transformer T1, the transformer T1 will increase the output voltage of the battery 100 based on the turns ratio and input it to the bus capacitor EC1; and when the mains 2 charges the energy storage system 1, the bus capacitor EC1 will input the output voltage of the mains 2 to the secondary side of the transformer T1. At this time, the transformer T1 will reduce the output voltage of the mains 2 based on the turns ratio and input it to the battery 100.

[0064] Specifically, when the battery 100 needs to be charged, the DC power output by the battery 100 will be converted into AC power through the first bridge unit and then input into the primary side of the transformer T1. After receiving the AC power, the transformer T1 will amplify the amplitude of the AC power accordingly based on the turns ratio, and output the amplified AC power to the second bridge unit through the resonant inductor L3 and the resonant capacitor C3. At this time, the second bridge unit will convert the amplified AC power into DC power and input it into the bus capacitor EC1. Among them, when the battery 100 is in the feeding state, the voltage input to the transformer T1 is also small, and because the turns ratio of the transformer T1 is fixed, the voltage input to the bus capacitor EC1 is also small, so that the output voltage of the voltage conversion module 32 does not match the output voltage of the mains 2. Therefore, the present application sets two windings N2 and N3 connected in series on the secondary side of the transformer T1, so that when the battery 100 is in the feeding state, the winding N3 is controlled to work simultaneously with the winding N2 to change the turns ratio of the transformer T1, so that the output voltage of the transformer T1 is further amplified, thereby increasing the amplitude of the output voltage of the voltage conversion module 32. When the voltage on the bus capacitor EC1 is greater than the second preset value, that is, the output voltage of the energy storage system 1 is consistent with the output voltage amplitude of the mains 2, the switching module 33 will switch the connection state of the transformer T1 to the second connection state, that is, the winding N3 of the transformer T1 does not participate in the voltage conversion. When the transformer T1 switches the connection state, the mains 2 also completes the phase lock and starts to charge the energy storage system 1.

[0065] Furthermore, when the output voltage of the energy storage system 1 is consistent with the output voltage amplitude of the mains 2, the mains 2 will output AC power to the conversion module 200, and the AC power is converted into DC power by the conversion circuit 200 and then input into the second bridge unit, so that the DC power is converted into AC power by the second bridge unit and then input into the transformer T1. At this time, the transformer T1 will reduce the AC power accordingly based on the turns ratio, and input the reduced AC power into the first bridge unit, so that the first bridge unit converts the reduced AC power into DC power, and inputs the DC power into the battery 100 to charge the battery 100. It should be noted that the transformer T1 mainly converts the voltage of the input AC power during operation, and the voltage stored in the battery 100 is mainly DC power. Therefore, the input voltage is converted from AC to DC by introducing the first bridge unit and the second bridge unit to meet the working voltage requirements of each device.

[0066] Further explanation, before the mains 2 starts to charge the energy storage system 1, the transformer T1 needs to be switched to the original turns ratio to avoid high-power charging current from damaging the transformer T1. It can be known that the transformer includes windings N1, N2 and N3, and the winding N3 is only used to charge the bus capacitor EC1 when the battery 100 is in the feeding state, and when the mains 2 charges the energy storage system 1, the winding N3 does not participate in the work, that is, no large current will flow through the winding N3. Therefore, in some embodiments, the copper wire diameter used in the winding N3 is set to be smaller than the copper wire diameter of the winding N1 and the winding N2, so as to save circuit costs, wherein the copper wire diameter is closely related to the maximum current that can be carried. Therefore, when the mains 2 normally charges the energy storage system 1, by disconnecting the connection of the winding N3, the high-power charging current will not flow through the winding N3, thereby avoiding the high-power charging current from damaging the winding N3, that is, avoiding the high-power charging current from damaging the transformer T1.

[0067] In yet another embodiment, see Figure 2 , the sampling module 31 includes a battery voltage sampling unit 311, a mains voltage sampling unit 312 and a logic control unit 313;

[0068] The battery voltage sampling unit 311 is connected to the battery 100 and the logic control unit 313 respectively, the mains voltage sampling unit 312 is connected to the mains connection terminal 34 and the logic control unit 313 respectively, and the logic control unit 313 is connected to the switching module 33;

[0069] The battery voltage sampling unit 311 is used to collect the battery voltage of the battery 100 to determine whether the battery voltage is less than a first preset value and greater than a third preset value, and output a feeding signal when the battery voltage is less than the first preset value and greater than the third preset value, wherein the first preset value is greater than the third preset value;

[0070] The mains voltage sampling unit 312 is used to collect the mains voltage of the mains connection terminal 34 to determine whether the mains voltage is within a preset range, and output a power supply signal when the mains voltage of the mains connection terminal is within the preset range;

[0071] The logic control unit 313 is used to output a control signal to the switching module 33 when receiving the feeding signal and the power supply signal.

[0072] Specifically, when the energy storage system 1 needs to be charged, the battery voltage sampling unit 311 and the mains voltage sampling unit 312 will respectively collect the voltage of the battery 100 and the voltage of the mains 2, and determine whether the battery voltage and the mains voltage are within a preset range, that is, whether the battery voltage is less than the first preset value and greater than the third preset value, and whether the mains voltage is greater than the fourth preset value and less than the fifth preset value. If the battery voltage and the mains voltage are both within the preset range, the battery voltage sampling unit 311 will output a feed signal to the logic control unit 313, and the mains voltage sampling unit 312 will output a power supply signal to the logic control unit 313. When the logic control unit 313 receives the feed signal and the power supply signal, it will output a control signal to the switching module 33, so that the switching module 33 switches the connection state of the transformer T1 to the first connection state, thereby improving the turns ratio of the transformer T1.

[0073] It should be noted that if the battery voltage is less than the first preset value and less than the third preset value, the battery 100 is considered to be scrapped, and at this time, the battery 100 cannot be used. If the battery voltage is greater than the first preset value, it is considered that the output voltage of the energy storage system 1 is the same as the output voltage amplitude of the mains, and at this time, the transformer T1 is maintained to work in the second connection state. If the mains voltage is less than the fourth preset value or greater than the fifth preset value, it is considered that the output voltage of the mains 2 is not within the preset range. At this time, regardless of whether the voltage output by the voltage conversion module 32 meets the requirements, the mains 2 cannot charge the energy storage system 1.

[0074] In some embodiments, Figure 3 As shown, the battery voltage sampling unit 311 includes a comparator U1, a comparator U2 and an AND gate U5; the mains voltage sampling unit 312 includes a comparator U3, a comparator U4 and an AND gate U6; the logic control unit 313 includes an AND gate U7;

[0075] The positive input terminal of the comparator U1 is used to receive the battery voltage, the reverse input terminal of the comparator U1 is connected to the third preset value, the positive input terminal of the comparator U2 is connected to the first preset value, the reverse input terminal of the comparator U2 is used to receive the battery voltage, the output terminal of the comparator U1 and the output terminal of the comparator U2 are both connected to the input terminal of the AND gate U5, and the output terminal of the AND gate U5 is connected to the logic control unit 313.

[0076] The positive input terminal of the comparator U3 is used to receive the mains voltage of the mains connection terminal 34, the reverse input terminal of the comparator U3 is connected to the fourth preset value, the positive input terminal of the comparator U4 is connected to the fifth preset value, the reverse input terminal of the comparator U4 is used to receive the voltage of the mains connection terminal 34, the output terminal of the comparator U3 and the output terminal of the comparator U4 are both connected to the input terminal of the AND gate U6, the output terminal of the AND gate U6 is connected to the input terminal of the AND gate U7, the input terminal of the AND gate U7 is also connected to the output terminal of the AND gate U5, and the output terminal of the AND gate U7 is connected to the switching module 33, wherein the fourth preset value is less than the fifth preset value.

[0077] Specifically, when the battery voltage is less than the first preset value and greater than the third preset value, the comparator U1 and the comparator U2 will both output a high level to the AND gate U5, and the AND gate U5 will output a high level to the input end of the AND gate U7 after receiving two high levels; at the same time, if the mains voltage is also greater than the fourth preset value and less than the fifth preset value, the AND gate U6 will also output a high level to the AND gate U7, and when the AND gate U7 receives two high levels, it will output a high level (control signal) to the switching module 33, so that the switching module 33 switches the transformer T1 to the first connection state. If the battery voltage or the mains voltage is not within the preset range, one of the comparators U1, U2, U3 and U4 will output a low level, so that the AND gate U5 or the AND gate U6 outputs a low level, and the AND gate U7 will also output a low level. At this time, the switching module 33 does not switch the connection state of the transformer T1 because it does not receive a control signal, and the transformer T1 still maintains the original turns ratio.

[0078] It can be known that when the battery voltage is lower than the third preset value, the transformer T1 will maintain the original turns ratio. However, because the battery voltage is too low, the voltage on the bus capacitor EC1 cannot reach the second preset value, so that the output voltage of the energy storage system 1 is inconsistent with the output voltage amplitude of the mains 2, resulting in the mains 2 being unable to charge the energy storage system 1. That is, when the voltage conversion module 32 works normally, but the mains 2 does not charge the energy storage system 1, it is considered that the battery 100 is in a scrap state.

[0079] In some embodiments, Figure 2 As shown, the charging control circuit 100 further includes a grid-connected relay 36 and a control module 37 for controlling the operation of the grid-connected relay 36, and the voltage conversion module 32 is also connected to the mains connection terminal 34 through the grid-connected relay 36;

[0080] The control module 37 is used for delaying a preset time to output a grid-connected signal to control the grid-connected relay 36 to be attracted when the voltage on the bus capacitor EC1 is greater than the second preset value.

[0081] For details, please refer to Figure 4 , Figure 4 is a circuit diagram of a charging control circuit provided by another embodiment of the present invention, such as Figure 4 As shown, the grid-connected relay 36 includes a relay RLY2 and a relay RLY3, the connection end of the relay RLY2 is respectively connected to the output end of the conversion circuit 200 and the live wire of the mains connection terminal 34, the connection end of the relay RLY3 is respectively connected to the other output end of the conversion circuit 200 and the neutral wire of the mains connection terminal 34, and the coil end of the relay RLY2 and the coil end of the relay RLY3 are both connected to the control module 37 (not shown).

[0082] Specifically, when the detection module 35 detects that the voltage on the bus capacitor EC1 is greater than the second preset value, it is considered that the voltage on the bus capacitor EC1 matches the output voltage of the mains 2. At this time, the mains 2 completes phase locking, and the detection module 35 outputs a locking signal to the switching module 33, so that the switching module 33 switches the transformer T1 to the second connection state, that is, the winding N3 does not participate in the work. When the transformer T1 switches the connection state, the control module 37 outputs a voltage signal to the coil end of the relay RLY2 and the coil end of the relay RLY3 to control the relay RLY2 and the relay RLY3 to be attracted. When the relay RLY2 and the relay RLY3 are attracted, the voltage output by the mains 2 will be input to the voltage conversion module 32 through the relay RLY2, the relay RLY3 and the conversion circuit 200, so as to charge the battery 100 through the voltage conversion module 32. It should be noted that, since the copper wire diameter of the winding N3 is relatively small, in order to avoid the large current output by the AC power during charging from burning the winding N3, during charging, the closing time of the relay RLY2 and the relay RLY3 needs to be later than the time when the transformer T1 switches the connection state, thereby improving the safety of the circuit.

[0083] It can be known that when the mains voltage is not within the preset range, the control module 37 will control the relays RLY2 and RLY3 to be in an off state, thereby prohibiting the mains 2 from charging the energy storage system 1 .

[0084] In yet another embodiment, see Figure 2 , the detection module 35 includes an optical coupling isolation unit 351 and a detection unit 352;

[0085] The detection unit 352 is connected to the bus capacitor EC1 and the optical coupling isolation unit 351 respectively, and the optical coupling isolation unit 351 is connected to the switching module 33;

[0086] The detection unit 352 is used to detect the voltage of the bus capacitor EC1, and when the voltage of the bus capacitor EC1 is greater than the second preset value, output a first driving signal to the optical coupling isolation unit 351;

[0087] The optical coupling isolation unit 351 is used to output a locking signal to the switching module 33 when receiving the first driving signal.

[0088] Specifically, when the transformer T1 outputs voltage to the bus capacitor EC1, the detection unit 352 detects the voltage on the bus capacitor EC1 in real time to determine whether the voltage on the bus capacitor EC1 is greater than a second preset value. When the voltage on the bus capacitor EC1 is greater than the second preset value, the detection unit 352 outputs a first drive signal to the optical coupling isolation unit 351, so that the optical coupling isolation unit 351 outputs a locking signal to the switching module 33 based on the first drive signal, so that the switching module 33 switches the transformer T1 to the second connection state according to the locking signal.

[0089] When the voltage on the bus capacitor EC1 is less than the second preset value, the detection unit 352 will output a second drive signal to the optocoupler isolation unit 351. At this time, the optocoupler isolation unit 351 will not output a signal to the switching module 33. The switching module 33 will switch the connection state of the transformer T1 according to the control signal output by the sampling module 31. It should be noted that the second preset value is set according to the output voltage of the mains 2, and the second preset value is greater than 1.414 times the mains voltage.

[0090] In some embodiments, Figure 3 As shown, the detection unit 352 includes a resistor R7, a resistor R10 and a voltage regulator ZD1; the optical coupling isolation unit 351 includes an optical coupler U8, a resistor R8 and a resistor R9;

[0091] The resistor R7 is connected to the bus capacitor EC1 and the resistor R10 respectively. The resistor R7 is also connected to the cathode of the voltage regulator tube ZD1. The anode of the voltage regulator tube ZD1 is connected to the optical coupling isolation unit 351. The resistor R10 is also used for grounding.

[0092] The input side of the optical coupler U8 is connected to the anode of the voltage regulator tube ZD1 through the resistor R9 , and the output side of the optical coupler U8 is connected to the switching module 33 through the resistor R8 .

[0093] Specifically, when the voltage of the bus capacitor EC1 is greater than the second preset value, the voltage of the bus capacitor will break down the voltage regulator ZD1 after being divided by resistors R7 and R10. When the voltage regulator ZD1 is broken down, the divided voltage will be input to the optocoupler U8. When the input side of the optocoupler U8 receives an electrical signal, the light emitter in the optocoupler U8 will emit light, and the light receiver in the optocoupler U8 will generate current after receiving the light, and output the current (locking signal) from the output side. At this time, the switching module 33 will receive the locking signal and change the connection state of the transformer T1 based on the locking signal. When the voltage on the bus capacitor EC1 is less than the second preset value, the voltage regulator ZD1 is in the cut-off state. At this time, the voltage of the bus capacitor after the voltage division will not be input to the optocoupler U8, and the optocoupler U8 will not work.

[0094] In another embodiment, please combine Figure 2 and Figure 3 , the switching module 33 includes a relay RLY1 and a control unit 331;

[0095] The connection end of the contact group of the relay RLY1 is connected to the winding N2 or the winding N3 respectively, the common end of the contact group of the relay RLY1 is connected to the high voltage side of the voltage conversion module 32, the coil end of the relay RLY1 is connected to the control unit 331, and the control unit 331 is also connected to the sampling module 31 and the detection module 35 respectively;

[0096] The control unit 331 is used to receive the control signal output by the sampling module 32, and switch the connection end of the contact group of the relay RLY1 to be connected to the winding N3 based on the control signal; and

[0097] The locking signal output by the detection module 35 is received, and the connection end of the contact group of the relay RLY1 is switched to be connected to the winding N2 according to the locking signal.

[0098] In another embodiment, see Figure 3 , the control unit 331 includes a switch tube Q21, a resistor R1 and a resistor R2;

[0099] The control end of the switch tube Q21 is connected to the sampling module 31 and the detection module 35 respectively through the resistor R2, the first end of the switch tube Q21 is connected to the coil end of the relay RLY1 through the resistor R1, and the second end of the switch tube Q21 is used for grounding.

[0100] Specifically, when the AND gate U7 outputs a high level (control signal), the switch tube Q21 is turned on based on the high level signal. At this time, the power supply VCC flows into the ground terminal through the coil end of the relay RLY1 and the switch tube Q21, and current flows through the coil end of the relay RLY1. When current flows through the coil end of the relay RLY1, the contact group of the relay RLY1 will switch to connect pins 3 and 5, thereby increasing the turns ratio of the transformer T1. When the voltage on the bus capacitor EC1 is greater than the second preset value, the switch tube Q21 will receive a locking signal and be turned off based on the locking signal. When the switch tube Q21 is turned off, no current flows through the coil end of the relay RLY1, and the contact group of the relay RLY1 will switch back to connect pins 3 and 4, thereby switching the turns ratio of the transformer T1 to the original turns ratio.

[0101] In some embodiments, please combine Figure 3 and Figure 4 , assuming that the turns ratio of the winding N1 and the winding N2 of the transformer T1 is 1:7, and the turns ratio of the winding N1 and the winding N3 is 1:3; the first preset value is 25V, and the third preset value is 18V; the voltage of the mains 2 is 120V, the fourth preset value is 114V, and the fifth preset value is 126V; when the second preset value is 178V, if the battery voltage collected by the battery voltage sampling unit 311 is 20V, and the mains voltage collected by the mains voltage sampling unit 312 is 120V, then the comparator U1, the comparator U2 and the comparator U3, the comparator U4 will all output a high level, so that the AND gate U7 outputs a high level. When the high level of the AND gate U7 is input to the switch tube Q21, the switch tube Q21 is turned on, and the 3rd and 5th pins of the relay RLY1 are connected. At this time, according to the turns ratio N1 of the transformer T1: (N2+N3), the transformer T1 will output a 200V voltage (turns ratio*battery voltage) to the bus capacitor EC1. When the voltage on the bus capacitor EC1 is 200V, the voltage regulator tube ZD1 will be broken down, so that the optocoupler U8 will output a low-level signal (locking signal) to the switch tube Q21, thereby switching the relay RLY1 to connect pins 3 and 4, so that the transformer T1 is switched to the second connection state; when the transformer T1 is switched to the second connection state, the relay RLY2 and the relay RLY3 are switched to the energized state, the energy storage system 1 is connected to the mains, and the voltage conversion module 32 will reduce the mains voltage to the battery voltage. Based on this, the energy storage system 1 can be charged normally through the mains 2.

[0102] Among them, if the battery voltage collected by the battery voltage sampling unit 311 is greater than 25V, the 3rd and 4th pins of the relay RLY1 are connected, and the voltage on the bus capacitor EC1 is determined to be greater than 175V according to the turns ratio of the transformer T1, so that the voltage output by the conversion circuit 200 is the same as the amplitude of the mains voltage, so that the mains 2 can normally charge the energy storage system 1.

[0103] An embodiment of the present invention provides a charging control circuit, which includes a sampling module, a voltage conversion module, a switching module, a mains connection terminal, and a detection module; the low voltage side of the voltage conversion module is connected to the battery, the high voltage side of the voltage conversion module is connected to the mains connection terminal, the transformer of the voltage conversion module is connected to the switching module and the detection module respectively, the switching module is connected to the sampling module and the detection module respectively, and the sampling module is also used to connect to the battery. The sampling module is used to collect the battery voltage, and when the battery voltage is less than a first preset value, the switching module controls the switching module to switch the transformer to a first connection state to increase the turns ratio of the transformer, thereby increasing the amplitude of the output voltage of the voltage conversion module, so that the output voltage of the voltage conversion module meets the requirements, and then the mains can charge the battery normally. After the amplitude of the output voltage of the voltage conversion module is increased, the detection module will output a locking signal to the switching module when the voltage of the high-voltage side bus capacitor is greater than a second preset value, so that the switching module controls the transformer to switch to the second connection state, thereby changing the turns ratio of the transformer to the original turns ratio, thereby avoiding resource waste caused by an excessively large transformer turns ratio during mains charging. The transformer turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A charging control circuit, characterized in that: The charging control circuit includes a sampling module, a voltage conversion module, a switching module, a mains connection terminal and a detection module; The low voltage side of the voltage conversion module is connected to the battery, the high voltage side of the voltage conversion module is respectively connected to the detection module and the mains connection end, the transformer of the voltage conversion module is connected to the switching module, the switching module is respectively connected to the sampling module and the detection module, and the sampling module is also used to connect to the battery; The sampling module is used to collect the battery voltage, and when the battery voltage is less than a first preset value, output a control signal to the switching module so that the switching module controls the transformer to switch to the first connection state; The detection module is used to output a locking signal to the switching module when the voltage of the bus capacitor on the high-voltage side is greater than a second preset value, so that the switching module controls the transformer to switch to a second connection state, wherein the transformer turns ratio corresponding to the first connection state is greater than the transformer turns ratio corresponding to the second connection state; Wherein, the sampling module includes a battery voltage sampling unit, a mains voltage sampling unit and a logic control unit; The battery voltage sampling unit is connected to the battery and the logic control unit respectively, the mains voltage sampling unit is connected to the mains connection terminal and the logic control unit respectively, and the logic control unit is connected to the switching module; The battery voltage sampling unit is used to collect the battery voltage of the battery to determine whether the battery voltage is less than a first preset value and greater than a third preset value, and output a feeding signal when the battery voltage is less than the first preset value and greater than the third preset value, wherein the first preset value is greater than the third preset value; The mains voltage sampling unit is used to collect the mains voltage of the mains connection end to determine whether the mains voltage is within a preset range, and output a power supply signal when the mains voltage of the mains connection end is within the preset range; The logic control unit is used to output a control signal to the switching module when receiving the feeding signal and the power supply signal.

2. The charging control circuit according to claim 1, characterized in that: The sampling module is also connected to the mains connection terminal, and is used to collect the voltage of the mains connection terminal, and output a control signal when the voltage of the mains connection terminal is within a preset range and the battery voltage is less than a first preset value.

3. The charging control circuit according to claim 2, characterized in that: The battery voltage sampling unit includes a comparator U1, a comparator U2 and an AND gate U5; The positive input terminal of the comparator U1 is used to receive the battery voltage, the reverse input terminal of the comparator U1 is connected to the third preset value, the positive input terminal of the comparator U2 is connected to the first preset value, the reverse input terminal of the comparator U2 is used to receive the battery voltage, the output terminal of the comparator U1 and the output terminal of the comparator U2 are both connected to the input terminal of the AND gate U5, and the output terminal of the AND gate U5 is connected to the logic control unit.

4. The charging control circuit according to claim 3, characterized in that: The mains voltage sampling unit includes a comparator U3, a comparator U4 and an AND gate U6; The logic control unit includes an AND gate U7; The positive input terminal of the comparator U3 is used to receive the voltage of the mains connection terminal, the reverse input terminal of the comparator U3 is connected to the fourth preset value, the positive input terminal of the comparator U4 is connected to the fifth preset value, the reverse input terminal of the comparator U4 is used to receive the voltage of the mains connection terminal, the output terminal of the comparator U3 and the output terminal of the comparator U4 are both connected to the input terminal of the AND gate U6, the output terminal of the AND gate U6 is connected to the input terminal of the AND gate U7, the input terminal of the AND gate U7 is also connected to the output terminal of the AND gate U5, and the output terminal of the AND gate U7 is connected to the switching module, wherein the fourth preset value is less than the fifth preset value.

5. The charging control circuit according to any one of claims 1 to 4, characterized in that: The primary side of the transformer is provided with a winding N1, and the secondary side of the transformer is provided with a winding N2 and a winding N3 connected in series with each other; The switching module includes a relay RLY1 and a control unit; The connection end of the contact group of the relay RLY1 is connected to the winding N2 or the winding N3 respectively, the common end of the contact group of the relay RLY1 is connected to the high voltage side of the voltage conversion module, the coil end of the relay RLY1 is connected to the control unit, and the control unit is also connected to the sampling module and the detection module respectively; The control unit is used to receive the control signal output by the sampling module, and switch the connection end of the contact group of the relay RLY1 to be connected to the winding N3 based on the control signal; and A locking signal output by the detection module is received, and the connection end of the contact group of the relay RLY1 is switched to be connected to the winding N2 according to the locking signal.

6. The charging control circuit according to claim 5, characterized in that: The control unit includes a switch tube Q21, a resistor R1 and a resistor R2; The control end of the switch tube Q21 is connected to the sampling module and the detection module respectively through the resistor R2, the first end of the switch tube Q21 is connected to the coil end of the relay RLY1 through the resistor R1, and the second end of the switch tube Q21 is used for grounding.

7. The charging control circuit according to any one of claims 1 to 4, characterized in that: The detection module includes an optical coupling isolation unit and a detection unit; The detection unit is connected to the bus capacitor and the optical coupling isolation unit respectively, and the optical coupling isolation unit is connected to the switching module; The detection unit is used to detect the voltage of the bus capacitor, and when the voltage of the bus capacitor is greater than the second preset value, output a first driving signal to the optical coupling isolation unit; The optical coupling isolation unit is used to output a locking signal to the switching module when receiving the first driving signal.

8. The charging control circuit according to claim 7, characterized in that: The detection unit includes a resistor R7, a resistor R10 and a voltage regulator tube ZD1; The resistor R7 is connected to the bus capacitor and the resistor R10 respectively. The resistor R7 is also connected to the cathode of the voltage regulator tube ZD1. The anode of the voltage regulator tube ZD1 is connected to the optical coupling isolation unit. The resistor R10 is also used for grounding.

9. The charging control circuit according to any one of claims 1 to 4, characterized in that: The charging control circuit further includes a grid-connected relay and a control module for controlling the operation of the grid-connected relay, and the voltage conversion module is also connected to the mains connection terminal through the grid-connected relay; The control module is used for delaying a preset time to output a grid-connected signal to control the grid-connected relay to be attracted when the voltage of the bus capacitor is greater than the second preset value.

10. An energy storage system, characterized in that: The energy storage system comprises: Battery; conversion circuit; and The charging control circuit according to any one of claims 1 to 9, wherein the charging control circuit is connected to the battery and the conversion circuit respectively.

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