Protection method and protection device for energy storage converter

Abstract

The invention discloses a protection method and a protection device for an energy storage converter. The protection method of the energy storage converter comprises the following steps: acquiring a historical voltage value and a current voltage value of a bus capacitor, and acquiring first output power of a battery and second output power of an alternating current power supply; calculating a change slope between the current voltage value and the historical voltage value of the bus capacitor; calculating a power ratio between the second output power and the first output power; determining a first comparison result according to the difference between the change slope and a first slope threshold; determining a second comparison result according to the difference between the current voltage value of the bus capacitor and the first voltage threshold value; determining a third comparison result according to the difference between the power ratio and a power ratio threshold; according to the first comparison result, the second comparison result and the third comparison result, it is determined that the release is released, and the energy storage converter is controlled to be turned off. The technical scheme provided by the embodiment of the invention has a relatively good protection effect on the energy storage converter.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply detection, and in particular to a protection method and a protection device for an energy storage converter. Background Art

[0002] When the energy storage converter is charging and discharging the battery, if the battery suddenly trips during the charging process, it will cause a sharp change in voltage, which is easy to damage the internal components of the energy storage converter or falsely report a fault. However, the existing technology cannot effectively judge the battery tripping, which is easy to trigger the wrong protection action, and there is a response time when the protection action is in progress, resulting in poor protection effect. Summary of the invention

[0003] The present invention provides a protection method and a protection device for an energy storage converter, so as to improve the protection effect on the energy storage converter.

[0004] According to one aspect of the present invention, a protection method for an energy storage converter is provided, which is applied to an energy storage converter system, wherein the energy storage converter system comprises: an energy storage converter, a battery, a bus capacitor and a release;

[0005] The energy storage converter is connected between the AC power supply and the battery, and the bus capacitor is connected in parallel with the energy storage converter; the release is connected between the battery and the energy storage converter;

[0006] The protection method of the energy storage converter comprises:

[0007] Acquire a historical voltage value and a current voltage value of the bus capacitor, and acquire a first output power of the battery and a second output power of the AC power source;

[0008] Calculating a change slope between a current voltage value and a historical voltage value of the bus capacitor; calculating a power ratio between the second output power and the first output power;

[0009] Determining a first comparison result according to a difference between the change slope and a first slope threshold;

[0010] Determining a second comparison result according to a difference between the current voltage value of the bus capacitor and the first voltage threshold;

[0011] determining a third comparison result according to a difference between the power ratio and the power ratio threshold;

[0012] According to the first comparison result, the second comparison result and the third comparison result, it is determined that the releaser is tripped, and the energy storage converter is controlled to be shut down.

[0013] Optionally, determining the first comparison result according to the difference between the change slope and the first slope threshold comprises:

[0014] When the change slope between the current voltage value of the bus capacitor and the historical voltage value is greater than the first slope threshold, it is determined that the change slope of the bus capacitor voltage is in an abnormal state;

[0015] When the change slope between the current voltage value and the historical voltage value of the bus capacitor is less than or equal to the first slope threshold, it is determined that the energy storage converter system is in a normal state.

[0016] Optionally, determining the second comparison result according to a difference between the current voltage value of the bus capacitor and a first voltage threshold includes:

[0017] When the current voltage value of the bus capacitor is greater than the first voltage threshold, determining that the voltage value of the bus capacitor is in an abnormal state;

[0018] When the current voltage value of the bus capacitor is less than or equal to the first voltage threshold, it is determined that the energy storage converter system is in a normal state.

[0019] Optionally, determining a third comparison result according to a difference between the power ratio and a power ratio threshold value includes:

[0020] When a power ratio between the second output power and the first output power is greater than the power ratio threshold, determining that the power ratio is in an abnormal state;

[0021] When the power ratio between the second output power and the first output power is less than or equal to the power ratio threshold, it is determined that the energy storage converter system is in a normal state.

[0022] Optionally, determining that the releaser is tripped according to the first comparison result, the second comparison result, and the third comparison result, and controlling the energy storage converter to shut down includes:

[0023] When the change slope of the bus capacitor voltage is in an abnormal state, the voltage value of the bus capacitor is in an abnormal state, and the power ratio value is in an abnormal state, it is determined that the releaser is tripped, and the energy storage converter is controlled to be shut down.

[0024] Optionally, after determining the first comparison result according to the difference between the change slope and the first slope threshold, the method further includes:

[0025] Determining a fourth comparison result according to a difference between the current voltage value of the bus capacitor and a second voltage threshold, wherein the second voltage threshold is greater than the first voltage threshold;

[0026] Determining a fifth comparison result according to a difference between the current voltage value of the bus capacitor and a third voltage threshold, wherein the third voltage threshold is less than the first voltage threshold;

[0027] According to the fourth comparison result and the fifth comparison result, it is determined that the bus capacitor voltage is abnormal, and the energy storage converter is controlled to be shut down.

[0028] Optionally, determining the fourth comparison result according to a difference between the current voltage value of the bus capacitor and a second voltage threshold comprises:

[0029] When the current voltage value of the bus capacitor is greater than the second voltage threshold, it is determined that the bus capacitor voltage is in an abnormal state, and the energy storage converter is controlled to be shut down.

[0030] Optionally, determining the fifth comparison result according to a difference between the current voltage value of the bus capacitor and a third voltage threshold comprises:

[0031] When the current voltage value of the bus capacitor is less than the third voltage threshold, the bus capacitor voltage is determined to be in an abnormal state, and the energy storage converter is controlled to be turned off;

[0032] When the current voltage value of the bus capacitor is greater than or equal to the third voltage threshold, it is determined that the energy storage converter system is in a normal state.

[0033] Optionally, the energy storage converter comprises: a first transmission end, a second transmission end and a control end; the first transmission end is connected to the AC power supply, and the second transmission end is connected to the battery;

[0034] The controlling the energy storage converter to shut down comprises:

[0035] When the energy storage converter system is in an abnormal state, a control signal is sent to the control end of the energy storage converter to control the energy storage converter to stop working and / or control the first transmission end and the second transmission end to be turned off.

[0036] According to another aspect of the present invention, there is provided a protection device for an energy storage converter, for protecting an energy storage converter system, wherein the energy storage converter system comprises: an energy storage converter, a battery, a bus capacitor and a release;

[0037] The energy storage converter is connected between the AC power supply and the battery, and the bus capacitor is connected in parallel with the energy storage converter; the release is connected between the battery and the energy storage converter;

[0038] The protection device of the energy storage converter comprises:

[0039] A data acquisition module, used to acquire a historical voltage value and a current voltage value of the bus capacitor, and to acquire a first output power of the battery and a second output power of the AC power source;

[0040] A calculation module, used to calculate the change slope between the current voltage value and the historical voltage value of the bus capacitor; and calculate the power ratio between the second output power and the first output power;

[0041] A judgment module, configured to determine a first comparison result according to a difference between the change slope and a first slope threshold; determine a second comparison result according to a difference between the current voltage value of the bus capacitor and the first voltage threshold; and determine a third comparison result according to a difference between the power ratio and the power ratio threshold;

[0042] A control module is used to determine that the releaser is tripped according to the first comparison result, the second comparison result and the third comparison result; and to control the energy storage converter to shut down.

[0043] The technical solution provided by the embodiment of the present invention can detect the change slope of the bus capacitor voltage, the bus capacitor voltage and the power ratio by acquiring the bus capacitor voltage, the first output power of the battery and the second output power of the AC power supply. When all three are in an abnormal state, it can be determined that the battery is tripped, and the energy storage inverter can be controlled to shut down. This setting avoids the misjudgment caused by transient phenomena caused by external interference to the battery or AC power supply, and will not cause misprotection of the energy storage inverter. In summary, the present invention realizes the tripping judgment of the battery without adding additional hardware protection measures, thereby ensuring the reliable operation of the energy storage inverter.

[0044] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces 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 creative work.

[0046] Figure 1 is a structural schematic diagram of an energy storage converter system provided according to an embodiment of the present invention;

[0047] Figure 2is a flow chart of a protection method for an energy storage converter provided according to an embodiment of the present invention;

[0048] Figure 3 is a flow chart of another method for protecting an energy storage converter provided according to an embodiment of the present invention;

[0049] Figure 4 is a flow chart of another method for protecting an energy storage converter provided according to an embodiment of the present invention;

[0050] Figure 5 It is a structural schematic diagram of a protection device for an energy storage converter provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] An embodiment of the present invention provides a protection method for an energy storage converter, which is applied to an energy storage converter system. Figure 1 A schematic diagram of the structure of an energy storage converter system provided by an embodiment of the present invention. Figure 1 The energy storage converter system includes: an energy storage converter 1, a battery 2, a bus capacitor 3 and a trip device 4. The energy storage converter 1 is connected between the AC power supply and the battery 2, the bus capacitor 3 is connected in parallel with the energy storage converter 1; the trip device 4 is connected between the battery 2 and the energy storage converter 1. It can be understood that Figure 1The energy storage converter 1 in the figure only shows the conversion circuit part by way of example, and is only one of the conversion circuit topologies of the energy storage converter 1. It does not limit the conversion circuit of the energy storage converter 1 / energy storage converter. The conversion circuit of the energy storage converter 1 can be any circuit that can realize the conversion function, and the energy storage converter 1 can be any energy storage converter that can realize the conversion function. Figure 2 A flow chart of a protection method for an energy storage converter provided by an embodiment of the present invention. Figure 2 , the protection methods of energy storage converter include:

[0054] S110, obtaining a historical voltage value and a current voltage value of the bus capacitor, and obtaining a first output power of the battery and a second output power of the AC power source.

[0055] Among them, when the energy storage inverter is charging and discharging the battery, the bus capacitor has two states: charging and discharging. When the energy storage inverter is charging, the electric energy of the AC power supply is charged to the bus capacitor through the energy storage inverter, and the voltage of the bus capacitor rises. When the energy storage inverter is discharging, the bus capacitor is discharged and the voltage of the bus capacitor decreases. When the battery is tripped, the voltage of the bus capacitor will change to a certain extent, and the first output power of the battery will continue to decrease. Therefore, it is possible to judge whether the battery is tripped by detecting the voltage change of the bus capacitor and the change of the output power between the battery and the AC power supply.

[0056] S120, calculating a change slope between a current voltage value and a historical voltage value of the bus capacitor; and calculating a power ratio between the second output power and the first output power.

[0057] The historical voltage value may be an average voltage value before the current moment or a voltage value at a certain moment.

[0058] S130: Determine a first comparison result according to a difference between the change slope and a first slope threshold.

[0059] Among them, when the change slope between the current voltage value and the historical voltage value of the bus capacitor exceeds the set first slope threshold, it means that the change slope of the bus capacitor voltage is an abnormal state, and the abnormality may also be caused by bus voltage fluctuations, surges, etc., so it cannot be determined at this time that the battery has a tripping fault. Exemplarily, the first slope threshold can be determined based on the capacitance value of the bus capacitor and the equivalent resistance of the energy storage converter. When the product between the capacitance value of the bus capacitor and the equivalent resistance of the energy storage converter is larger, the value of the first slope threshold is also larger. Exemplarily, the first slope threshold can also be determined based on the capacitance value of the bus capacitor and the power of the energy storage converter. The smaller the capacitance value of the bus capacitor and the greater the power of the energy storage converter, the higher the first slope threshold. The first slope threshold can be specifically determined based on the actual application situation, and is not limited here.

[0060] S140. Determine a second comparison result according to a difference between a current voltage value of the bus capacitor and the first voltage threshold.

[0061] Among them, the current voltage value of the bus capacitor continues to be judged. When the current voltage value of the bus capacitor is greater than the first voltage threshold, it indicates that the voltage value of the bus capacitor is abnormal. Exemplarily, the first voltage threshold is the value of the safe operation of the bus voltage, which is generally between the maximum and minimum values ​​of the operating voltage of the energy storage inverter. It can be adaptively adjusted according to the power of the energy storage inverter and the capacitance value of the bus capacitor. For example, when the power of the energy storage inverter is fixed, the smaller the capacitance value of the bus capacitor, the higher the first voltage threshold; when the capacitance value of the bus capacitor is fixed, the higher the power of the energy storage inverter, the higher the first voltage threshold. The first voltage threshold can be specifically debugged and determined according to the actual application situation, and is not limited here.

[0062] S150: Determine a third comparison result according to a difference between the power ratio and the power ratio threshold.

[0063] Among them, by calculating the ratio between the second output power of the AC power supply and the first output power of the battery, the operating condition of the battery can be judged. When the power ratio is greater than the power ratio threshold, it means that the first output power of the battery is too small, or the output power of the AC power supply is too large, and the power ratio is judged to be in an abnormal state. Exemplarily, the power ratio threshold in a specific embodiment can be between 0.9-0.999, and the power ratio threshold can be determined by the operating efficiency of the energy storage inverter. When the operating efficiency of the energy storage inverter is higher, the power ratio threshold is smaller. In other embodiments, the power ratio threshold can be specifically determined according to the actual application situation, and is not limited here.

[0064] S160: Determine that the releaser is tripped according to the first comparison result, the second comparison result, and the third comparison result, and control the energy storage converter to shut down.

[0065] Among them, when the first comparison result indicates that the change slope of the bus capacitor voltage is abnormal, the second comparison result indicates that the voltage value of the bus capacitor is abnormal, and the third comparison result indicates that the power ratio is abnormal, it can be determined that the release is tripped. At this time, the protection of the energy storage converter can be started, the energy storage converter can be controlled to shut down, and the connection with the AC power supply can be disconnected to prevent damage to the energy storage converter or the bus capacitor.

[0066] The technical solution provided by the embodiment of the present invention can detect the change slope of the bus capacitor voltage, the bus capacitor voltage and the power ratio by acquiring the bus capacitor voltage, the first output power of the battery and the second output power of the AC power supply. When all three are in an abnormal state, it can be determined that the battery is tripped, and the energy storage inverter can be controlled to shut down. This setting avoids the misjudgment caused by transient phenomena caused by external interference to the battery or AC power supply, and will not cause misprotection of the energy storage inverter. In summary, the present invention realizes the tripping judgment of the battery without adding additional hardware protection measures, thereby ensuring the reliable operation of the energy storage inverter.

[0067] On the basis of the above embodiments, optionally, according to the difference between the change slope and the first slope threshold, determining the first comparison result includes: when the change slope between the current voltage value and the historical voltage value of the bus capacitor is greater than the first slope threshold, determining that the change slope of the bus capacitor voltage is an abnormal state. When the change slope between the current voltage value and the historical voltage value of the bus capacitor is less than or equal to the first slope threshold, determining that the energy storage converter system is in a normal state.

[0068] Among them, when the change slope of the voltage value of the bus capacitor is too large, it means that transient processes such as bus voltage fluctuation, power mutation, voltage sag or surge may have occurred in the energy storage converter system. In order to prevent the energy storage converter from malfunctioning, only the first comparison result is generated, and the energy storage converter is not controlled to perform corresponding protection actions. When the change slope of the voltage value of the bus capacitor does not reach the first slope threshold, it means that the energy storage converter system is in a normal state and there is no need to perform protection actions.

[0069] On the basis of the above embodiments, optionally, a second comparison result is determined according to the difference between the current voltage value of the bus capacitor and the first voltage threshold, including: when the current voltage value of the bus capacitor is greater than the first voltage threshold, determining that the voltage value of the bus capacitor is in an abnormal state; when the current voltage value of the bus capacitor is less than or equal to the first voltage threshold, determining that the energy storage inverter system is in a normal state.

[0070] Among them, when the voltage value of the bus capacitor is too high, it will cause the bus capacitor to break down, and the second comparison result is generated at this time. However, the fault may be caused by a transient phenomenon and may return to normal at the next moment, so no protection action is performed. When the current voltage value of the bus capacitor is less than or equal to the first voltage threshold, the energy storage converter system is in a normal state and no protection action needs to be performed.

[0071] On the basis of the above embodiments, optionally, determining the third comparison result according to the difference between the power ratio and the power ratio threshold value includes: when the power ratio between the second output power and the first output power is greater than the power ratio threshold value, determining that the power ratio is in an abnormal state. When the power ratio between the second output power and the first output power is less than or equal to the power ratio threshold value, determining that the energy storage converter system is in a normal state.

[0072] Among them, when the power ratio between the second output power and the first output power is too large, it may indicate that the output power of the AC power source is too large or the first output power of the battery is too small. In order to prevent the fault from being a transient phenomenon, the protection action is not performed temporarily. When the power ratio is less than or equal to the power ratio threshold, the energy storage converter system is in a normal state and there is no need to perform a protection action.

[0073] On the basis of the above embodiments, optionally, according to the first comparison result, the second comparison result and the third comparison result, determining that the releaser is tripped and controlling the energy storage converter to shut down includes: when the change slope of the bus capacitor voltage is abnormal, the voltage value of the bus capacitor is abnormal and the power ratio value is abnormal, determining that the releaser is tripped and controlling the energy storage converter to shut down.

[0074] Exemplarily, the release may include a relay. Wherein, when one or two of the first comparison result, the second comparison result and the third comparison result are abnormal, it may be a misjudgment caused by a transient phenomenon caused by external interference to the battery or the AC power supply. When the first comparison result, the second comparison result and the third comparison result are abnormal at the same time, the transient phenomenon can be excluded, the release is determined to be tripped, and the energy storage converter is controlled to be turned off. It can be understood that at this time, controlling the energy storage converter to be turned off includes: controlling the energy storage converter to stop working and / or controlling the connection between the energy storage converter and the AC power supply to be turned off. Optionally, controlling the energy storage converter to stop working includes but is not limited to controlling the conversion circuit (bidirectional DC-AC circuit) to be turned off, wherein the conversion circuit of the energy storage converter can be turned off by not sending a PWM drive signal to the conversion circuit, or sending a PWM drive wave signal for controlling each transistor in the conversion circuit to be in an off state. Optionally, the connection between the energy storage converter and the AC power supply can be controlled to be turned off by disconnecting the connection switch between the energy storage converter and the AC power supply.

[0075] Figure 3 A flowchart of another method for protecting an energy storage converter provided by an embodiment of the present invention. Figure 3 Based on the above embodiments, optionally, after determining the first comparison result according to the difference between the change slope and the first slope threshold in S130, the method further includes:

[0076] S170. Determine a fourth comparison result according to a difference between a current voltage value of the bus capacitor and the second voltage threshold.

[0077] Among them, the fourth comparison result can be used to reflect the magnitude relationship between the current voltage value of the bus capacitor and the second voltage threshold. Exemplarily, the second voltage threshold can be the maximum value of the operating voltage of the energy storage converter, and the second voltage threshold is greater than the first voltage threshold. If the first comparison result indicates that the change slope of the voltage value of the bus capacitor is too large, and the current voltage value of the bus capacitor is greater than the maximum value of the operating voltage of the energy storage converter, the fourth comparison result is determined to be abnormal.

[0078] S180. Determine a fifth comparison result according to a difference between a current voltage value of the bus capacitor and a third voltage threshold.

[0079] Among them, the fifth comparison result can be used to reflect the magnitude relationship between the current voltage value of the bus capacitor and the third voltage threshold. Exemplarily, the third voltage threshold may be the minimum value of the operating voltage of the energy storage converter, and the third voltage threshold is less than the first voltage threshold. If the first comparison result indicates that the change slope of the voltage value of the bus capacitor is too large, and the current voltage value of the bus capacitor is less than the minimum value of the operating voltage of the energy storage converter, the fifth comparison result is determined to be abnormal.

[0080] S190. Determine that the bus capacitor voltage is abnormal based on the fourth comparison result and the fifth comparison result, and control the energy storage converter to shut down.

[0081] When any one of the fourth comparison result and the fifth comparison result is abnormal, it can be determined that the bus capacitor voltage is abnormal. To prevent damage to the bus capacitor, the energy storage converter is controlled to be shut down.

[0082] On the basis of the above embodiments, optionally, according to the difference between the current voltage value of the bus capacitor and the second voltage threshold, determining the fourth comparison result includes: when the current voltage value of the bus capacitor is greater than the second voltage threshold, determining that the bus capacitor voltage is in an abnormal state, and controlling the energy storage converter to shut down. It can be understood that at this time, controlling the energy storage converter to shut down includes: controlling the conversion circuit of the energy storage converter to shut down and / or controlling the connection between the energy storage converter and the battery / AC power supply to shut down.

[0083] Among them, when the current voltage value of the bus capacitor is greater than the second voltage threshold, it means that the current voltage value exceeds the maximum operating voltage of the energy storage inverter. If the energy storage inverter continues to operate, it may cause the energy storage inverter to be overvoltage and damaged. Therefore, the energy storage inverter can be controlled to shut down to protect the bus capacitor and the energy storage inverter.

[0084] On the basis of the above embodiments, optionally, according to the difference between the current voltage value of the bus capacitor and the third voltage threshold, determining the fifth comparison result includes: when the current voltage value of the bus capacitor is less than the third voltage threshold, determining that the bus capacitor voltage is in an abnormal state, and controlling the energy storage converter to shut down. When the current voltage value of the bus capacitor is greater than or equal to the third voltage threshold, determining that the energy storage converter system is in a normal state.

[0085] Among them, when the current voltage value of the bus capacitor is not greater than the second voltage threshold, it is also necessary to compare the current voltage value with the third voltage threshold. If the current voltage value is less than the third voltage threshold, the bus capacitor is in a discharge state and has a lower voltage level. At this time, the energy storage inverter may not work normally, and the energy storage inverter can be controlled to shut down.

[0086] Continue to refer Figure 1 On the basis of the above embodiments, optionally, the energy storage converter 1 includes: a first transmission end, a second transmission end and a control end; the first transmission end is connected to the AC power supply, and the second transmission end is connected to the battery 2. Controlling the energy storage converter to shut down includes: when the energy storage converter system is in an abnormal state, sending a control signal to the control end of the energy storage converter 1 to control the energy storage converter 1 to stop working and / or control the first transmission end and the second transmission end to shut down.

[0087] Among them, the AC power supply can be a three-phase AC power including phase A, phase B and phase C, and the energy storage converter 1 can include a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5 and a sixth transistor Q6. The three-phase AC power of the first transmission end can be rectified by turning on or off each transistor, or the DC power of the second transmission end can be inverted. It can be understood that controlling the energy storage converter 1 to stop working includes but is not limited to controlling the conversion circuit of the energy storage converter 1 to stop working. When the energy storage converter system is abnormal, the energy storage converter 1 can turn off all the transistors in the conversion circuit of the energy storage converter and / or control the connection between the energy storage converter 1 and the battery 2 and the AC power supply to be turned off. Exemplarily, a switch can be provided inside the energy storage converter 1, and the switch can be controlled to be disconnected by a control signal, thereby turning off the first transmission end and the second transmission end of the energy storage converter 1.

[0088] Figure 4 A flowchart of another method for protecting an energy storage converter provided by an embodiment of the present invention. Figure 4 Based on the above embodiments, optionally, the method includes:

[0089] S210: Calculate the change slope between the current voltage value and the historical voltage value of the bus capacitor.

[0090] S220: Determine whether the change slope is greater than a first slope threshold. If yes, execute S230; if no, execute S270.

[0091] S230: Determine whether the current voltage value of the bus capacitor is greater than the first voltage threshold. If yes, execute S240; if no, return to execute S210.

[0092] S240: Calculate a power ratio between the second output power of the AC power source and the first output power of the battery.

[0093] S250: Determine whether the power ratio is greater than the power ratio threshold. If yes, execute S260; if no, return to execute S210.

[0094] S260: Determine battery tripping and control energy storage converter shutdown

[0095] S270: Determine whether the current voltage value of the bus capacitor is greater than the second voltage threshold. If yes, execute S300; if no, execute S280.

[0096] S280: Determine whether the current voltage value of the bus capacitor is less than a third voltage threshold. If yes, execute S290; if no, execute S300.

[0097] S290, the energy storage converter operates normally.

[0098] S300, determining that the bus capacitor voltage is abnormal, and controlling the energy storage converter to shut down.

[0099] The technical solution provided by the embodiment of the present invention can detect the change slope of the bus capacitor voltage, the bus capacitor voltage and the power ratio by acquiring the bus capacitor voltage, the first output power of the battery and the second output power of the AC power supply. When all three are in an abnormal state, it can be determined that the battery is tripped and the energy storage converter is controlled to shut down. The determination of the abnormal bus capacitor voltage is also achieved by detecting the voltage of the bus capacitor. This setting avoids the misjudgment caused by transient phenomena caused by external interference to the battery or AC power supply, and will not cause misprotection of the energy storage converter. In summary, the present invention realizes the determination of the tripping of the battery and the fault of the bus capacitor voltage without adding additional hardware protection measures, thereby ensuring the reliable operation of the energy storage converter.

[0100] The embodiment of the present invention also provides a protection device for an energy storage inverter, which is used to protect the energy storage inverter system. The protection device for the energy storage inverter can be implemented in the form of hardware and / or software, and the control device of the industrial computer can be configured in the energy storage inverter system. The energy storage inverter system includes: an energy storage inverter, a battery, a bus capacitor and a release; the energy storage inverter is connected between the AC power supply and the battery, and the bus capacitor is connected in parallel with the energy storage inverter; the release is connected between the battery and the energy storage inverter; Figure 5 A schematic diagram of the structure of a protection device for an energy storage converter provided by an embodiment of the present invention. Figure 5 , the protection device of the energy storage converter includes:

[0101] A data acquisition module 5 is used to acquire a historical voltage value and a current voltage value of the bus capacitor, and to acquire a first output power of the battery and a second output power of the AC power source;

[0102] Calculation module 6, used to calculate the change slope between the current voltage value and the historical voltage value of the bus capacitor; calculate the power ratio between the second output power and the first output power;

[0103] The judgment module 7 is used to determine the first comparison result according to the difference between the change slope and the first slope threshold; determine the second comparison result according to the difference between the current voltage value of the bus capacitor and the first voltage threshold; determine the third comparison result according to the difference between the power ratio and the power ratio threshold;

[0104] The control module 8 is used to determine that the releaser is tripped according to the first comparison result, the second comparison result and the third comparison result; and control the energy storage converter to shut down.

[0105] The protection device for the energy storage converter provided in the embodiment of the present invention can execute the protection method for the energy storage converter provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0106] Optionally, the judgment module 7 is further configured to determine a fourth comparison result according to a difference between a current voltage value of the bus capacitor and the second voltage threshold.

[0107] Optionally, the judgment module 7 is further configured to determine a fifth comparison result according to a difference between a current voltage value of the bus capacitor and a third voltage threshold.

[0108] Optionally, the control module 8 is further configured to determine that the bus capacitor voltage is abnormal according to the fourth comparison result and the fifth comparison result, and control the energy storage converter to shut down.

[0109] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0110] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A protection method for an energy storage converter, characterized in that: Applied to an energy storage converter system, the energy storage converter system comprising: an energy storage converter, a battery, a bus capacitor and a release; The energy storage converter is connected between the AC power supply and the battery, and the bus capacitor is connected in parallel with the energy storage converter; the release is connected between the battery and the energy storage converter; The protection method of the energy storage converter comprises: Acquire a historical voltage value and a current voltage value of the bus capacitor, and acquire a first output power of the battery and a second output power of the AC power source; Calculating a change slope between a current voltage value and a historical voltage value of the bus capacitor; calculating a power ratio between the second output power and the first output power; Determining a first comparison result according to a difference between the change slope and a first slope threshold; Determining a second comparison result according to a difference between the current voltage value of the bus capacitor and the first voltage threshold; determining a third comparison result according to a difference between the power ratio and the power ratio threshold; According to the first comparison result, the second comparison result and the third comparison result, it is determined that the releaser is tripped, and the energy storage converter is controlled to be shut down.

2. The protection method for the energy storage converter according to claim 1, characterized in that: Determining a first comparison result according to a difference between the change slope and a first slope threshold comprises: When the change slope between the current voltage value of the bus capacitor and the historical voltage value is greater than the first slope threshold, it is determined that the change slope of the bus capacitor voltage is in an abnormal state; When the change slope between the current voltage value and the historical voltage value of the bus capacitor is less than or equal to the first slope threshold, it is determined that the energy storage converter system is in a normal state.

3. The protection method for the energy storage converter according to claim 1, characterized in that: The determining a second comparison result according to a difference between the current voltage value of the bus capacitor and the first voltage threshold comprises: When the current voltage value of the bus capacitor is greater than the first voltage threshold, determining that the voltage value of the bus capacitor is in an abnormal state; When the current voltage value of the bus capacitor is less than or equal to the first voltage threshold, it is determined that the energy storage converter system is in a normal state.

4. The protection method for the energy storage converter according to claim 1, characterized in that: The determining a third comparison result according to a difference between the power ratio and the power ratio threshold value includes: When a power ratio between the second output power and the first output power is greater than the power ratio threshold, determining that the power ratio is in an abnormal state; When the power ratio between the second output power and the first output power is less than or equal to the power ratio threshold, it is determined that the energy storage converter system is in a normal state.

5. The protection method for the energy storage converter according to claim 1, characterized in that: Determining that the releaser is tripped according to the first comparison result, the second comparison result, and the third comparison result, and controlling the energy storage converter to shut down includes: When the change slope of the bus capacitor voltage is in an abnormal state, the voltage value of the bus capacitor is in an abnormal state, and the power ratio value is in an abnormal state, it is determined that the releaser is tripped, and the energy storage converter is controlled to be shut down.

6. The protection method for the energy storage converter according to claim 1, characterized in that: After determining the first comparison result according to the difference between the change slope and the first slope threshold, the method further includes: Determining a fourth comparison result according to a difference between the current voltage value of the bus capacitor and a second voltage threshold, wherein the second voltage threshold is greater than the first voltage threshold; Determining a fifth comparison result according to a difference between the current voltage value of the bus capacitor and a third voltage threshold, wherein the third voltage threshold is less than the first voltage threshold; According to the fourth comparison result and the fifth comparison result, it is determined that the bus capacitor voltage is abnormal, and the energy storage converter is controlled to be shut down.

7. The protection method for the energy storage converter according to claim 6, characterized in that: Determining the fourth comparison result according to the difference between the current voltage value of the bus capacitor and the second voltage threshold comprises: When the current voltage value of the bus capacitor is greater than the second voltage threshold, it is determined that the bus capacitor voltage is in an abnormal state, and the energy storage converter is controlled to be shut down.

8. The protection method for the energy storage converter according to claim 6, characterized in that: Determining a fifth comparison result according to a difference between the current voltage value of the bus capacitor and a third voltage threshold comprises: When the current voltage value of the bus capacitor is less than the third voltage threshold, the bus capacitor voltage is determined to be in an abnormal state, and the energy storage converter is controlled to be turned off; When the current voltage value of the bus capacitor is greater than or equal to the third voltage threshold, it is determined that the energy storage converter system is in a normal state.

9. The protection method for the energy storage converter according to claim 1, characterized in that: The energy storage converter comprises: a first transmission end, a second transmission end and a control end; the first transmission end is connected to the AC power source, and the second transmission end is connected to the battery; The controlling the energy storage converter to shut down comprises: When the energy storage converter system is in an abnormal state, a control signal is sent to the control end of the energy storage converter to control the energy storage converter to stop working and / or control the first transmission end and the second transmission end to be turned off.

10. A protection device for an energy storage converter, characterized in that: Used to protect an energy storage converter system, the energy storage converter system comprising: an energy storage converter, a battery, a bus capacitor and a release; The energy storage converter is connected between the AC power supply and the battery, and the bus capacitor is connected in parallel with the energy storage converter; the release is connected between the battery and the energy storage converter; The protection device of the energy storage converter comprises: A data acquisition module, used to acquire a historical voltage value and a current voltage value of the bus capacitor, and to acquire a first output power of the battery and a second output power of the AC power source; A calculation module, used to calculate the change slope between the current voltage value and the historical voltage value of the bus capacitor; and calculate the power ratio between the second output power and the first output power; A judgment module, configured to determine a first comparison result according to a difference between the change slope and a first slope threshold; determine a second comparison result according to a difference between the current voltage value of the bus capacitor and the first voltage threshold; and determine a third comparison result according to a difference between the power ratio and the power ratio threshold; A control module is used to determine that the releaser is tripped according to the first comparison result, the second comparison result and the third comparison result; and to control the energy storage converter to shut down.

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