Battery port protection circuit of energy storage inverter

Abstract

The utility model belongs to the technical field of battery protection, and provides an energy storage inverter battery port protection circuit, a power MOS tube and a current sampling circuit, a voltage sampling circuit and an overcurrent protection circuit are additionally arranged on the input side of an energy storage inverter battery, when the battery is short-circuited, battery current abnormity can be detected through battery input current signal sampling, and the battery port protection circuit is used for protecting the battery. Battery current sampling is carried out through a comparator protection circuit, it is recognized that the current exceeds a threshold value, an output signal of a comparator is turned to be low from high, a turning signal is transmitted to a DSP main control chip, and a DSP blocks a driving signal for driving an MOS Q5, so that connection between a battery port and an inverter DC / DC is disconnected, and the effect of protecting an inverter is achieved.

Description

Technical Field

[0001] The present application relates to the field of circuit protection technology, and in particular to a battery port protection circuit for an energy storage inverter. Background Art

[0002] The energy storage system consists of an energy storage inverter, energy storage batteries, AC appliances, and a power grid. The energy storage inverter, as the power conversion link, can convert the energy stored in the battery into AC power to power AC loads, or it can convert AC mains power into DC power and store it in the battery. Therefore, a power port is required between the energy storage inverter and the energy storage battery for connection. This can lead to abnormal wiring during the power port connection, including reverse connection or short circuit. Currently, most energy storage inverters on the market do not have corresponding protection functions for reverse connection or short circuit of the battery port. They can only be protected by the BMS control box of the energy storage battery. If the BMS control box protection fails, the inverter will be damaged. For example, if the wiring is reversed, the battery will short-circuit the battery through the DC / DC MOS tube body diode, causing damage to the inverter switch tube. If the body diode is damaged and opens, the inverter input electrolytic capacitor will explode and be damaged due to the reverse pressure. For example, if the wiring is short-circuited, due to the large capacity of the input electrolytic capacitor, the DC / DC takes a long time to respond to the short circuit on the battery side, and the corresponding protection time is also lengthened, increasing the risk of damage to the DC / DC switch tube. Utility Model Content

[0003] The present application provides a battery port protection circuit for an energy storage inverter. On the battery input side of the energy storage inverter, a power MOS tube and current sampling, voltage sampling, and overcurrent protection circuits are added to address the potential damage risks associated with reverse connection and short circuits in the corresponding battery ports of conventional energy storage inverter circuits.

[0004] Based on the design invention of a protection scheme for reverse connection and short circuit of battery ports of energy storage inverters, the entire design scheme is mainly divided into four parts: power MOS tube for switching power circuit, current sampling circuit, voltage sampling circuit, and overcurrent protection circuit.

[0005] Specifically, the energy storage inverter battery port protection circuit described in this application includes:

[0006] The source of the MOS tube Q5 is connected to the battery port BAT+, and the drain is connected to the input electrolytic capacitor C1+ and the DC / DC input+ terminal;

[0007] One end of the current sampling circuit is connected to the battery port BAT-, and the other end is connected to the main control chip DSP; the main control chip DSP is also connected to the MOS tube Q5;

[0008] The voltage sampling circuit is connected to the battery port BAT+ and the battery port BAT-;

[0009] One end of the overcurrent protection circuit is connected to the current sampling circuit, and the other end is connected to the main control chip DSP.

[0010] The current sampling circuit includes:

[0011] Current sampling resistor R2 and first operational amplifier circuit;

[0012] The current sampling resistor R2 is connected to the battery port BAT-;

[0013] The first operational amplifier circuit is connected in parallel with the current sampling resistor R2.

[0014] The first operational amplifier circuit includes a resistor R5, a resistor R9, a resistor R4 and an operational amplifier 1; the resistor R5 and the resistor R9 are connected to the input end of the operational amplifier 1, and the resistor R4 and the operational amplifier 1 are connected in parallel.

[0015] The voltage sampling circuit includes: a second operational amplifier circuit.

[0016] The second operational amplifier circuit includes a resistor R15, a resistor R16, a resistor R14 and an operational amplifier 2. The resistor R15 and the resistor R16 are connected to the input end of the operational amplifier 2, and the resistor R14 and the operational amplifier 2 are connected in parallel.

[0017] The overcurrent protection circuit includes: a comparator circuit;

[0018] The non-inverting input terminal of the comparator circuit is connected to the current sampling circuit;

[0019] The inverting input terminal of the comparator circuit is connected to the voltage divider circuit;

[0020] The output end of the comparator circuit is connected to the main control chip DSP.

[0021] Specifically, the output end of the comparator circuit is also connected to the MOS transistor Q6. The comparator circuit includes resistors R6, R8, R20, R18, R12, R11, transistor Q6, and an operational amplifier 3; the resistors R6, R8, and R20 are connected to the input end of the operational amplifier 3, and the resistors R18, R12, R11, and transistor Q6 are connected to the output end of the operational amplifier 3.

[0022] This application mainly adds a power MOS tube Q5 to the main power circuit, the source of the MOS tube is connected to the battery port input BAT+, and the drain is connected to the input electrolytic capacitor C1+ end and the DC / DC input + end.

[0023] When the battery is connected in the positive direction, the battery can normally provide energy to the DC / DC through the MOS tube. When the battery is connected in the reverse direction, the BAT_V battery voltage sampling has a negative voltage, and the MOS tube Q5 is not turned on. In this way, the power circuit is disconnected, so that the DC / DC MOS Q3 and Q4 will not short-circuit the battery through the internal body diode, and the electrolytic capacitor C1 will not be reversed in polarity, protecting the MOS Q3, Q4, and electrolytic capacitor C1 from damage.

[0024] When the battery is short-circuited, the battery current abnormality can be detected by sampling the battery input current signal. The battery current sampling passes through the comparator protection circuit, identifies that the current exceeds the threshold, flips the comparator output signal from high to low, and transmits the flip signal to the DSP main control chip. The DSP blocks the drive signal of the MOS Q5, thereby disconnecting the battery port from the inverter DC / DC, thereby protecting the inverter.

[0025] Compared with the existing technology, the beneficial effects of the technical solution of this application are:

[0026] The present application provides a battery port protection circuit for an energy storage inverter, which can reliably issue an alarm and disconnect the main power circuit for reverse connection and short circuit of the battery port, ensuring the safety and reliability of the inverter. The circuit scheme is relatively simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a battery port protection circuit for an energy storage inverter described in this application.

[0028] Figure 2 This is the power path diagram of the reverse battery connection described in this application.

[0029] Figure 3 This is the battery wiring short-circuit power path diagram described in this application.

[0030] Figure 4 This is the voltage sampling circuit diagram described in this application.

[0031] Figure 5 This is the current sampling circuit diagram described in this application.

[0032] Figure 6 This is the overcurrent protection circuit diagram described in this application DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] Please refer to Figure 1-3 , is a battery port protection circuit for an energy storage inverter described in this application, comprising: a power MOS tube for switching the power circuit, a current sampling circuit, a voltage sampling circuit, and an overcurrent protection circuit,

[0035] Specifically, the present application mainly adds a power MOS tube Q5 to the main power circuit, the source of the MOS tube is connected to the battery port input BAT+, and the drain is connected to the input electrolytic capacitor C1+ end and the DC / DC input + end. When the battery is connected in the positive direction, the battery can normally provide energy to the DC / DC through the MOS tube; when the battery is connected in the reverse direction, the BAT_V battery voltage sampling has a negative voltage, and the MOS tube Q5 is not turned on, so that the power circuit is disconnected, so that the DC / DC MOS Q3 and Q4 will not short-circuit the battery through the internal body diode, and the electrolytic capacitor C1 will not be reversed in polarity, protecting the MOS Q3, Q4, and the electrolytic capacitor C1 from damage. When the battery is short-circuited, the battery current abnormality can be detected by sampling the battery input current signal. The battery current sampling passes through the comparator protection circuit, identifies that the current exceeds the threshold, and flips the output signal of the comparator from high to low. The flip signal is transmitted to the DSP main control chip, and the DSP blocks the drive signal of the MOS Q5, thereby disconnecting the battery port from the inverter DC / DC, thereby protecting the inverter. That is, after Q5 is disconnected, the dotted short-circuit current path is disconnected.

[0036] One end of the current sampling circuit is connected to the battery port BAT-, and the other end is connected to the main control chip DSP; the main control chip DSP is also connected to the MOS tube Q5;

[0037] The present invention includes a battery voltage sampling circuit, which is composed of an operational amplifier circuit. The sampling voltage is sent to the DSP control chip, and the battery reverse connection and battery short circuit are determined by voltage sampling. Figure 4 As shown, the voltage sampling circuit is connected to the battery port BAT+ and the battery port BAT-;

[0038] The present invention adds an input current sampling resistor to the main power circuit to form a current sampling circuit with the operational amplifier circuit. The sampled current is sent to the DSP control chip and serves as the input of the battery overcurrent protection circuit. Figure 5 As shown, the current sampling circuit includes:

[0039] Current sampling resistor R2 and first operational amplifier circuit;

[0040] The current sampling resistor R2 is connected to the battery port BAT-;

[0041] The first operational amplifier circuit is connected in parallel with the current sampling resistor R2.

[0042] The first operational amplifier circuit includes a resistor R5, a resistor R9, a resistor R4 and an operational amplifier 1; the resistor R5 and the resistor R9 are connected to the input end of the operational amplifier 1, and the resistor R4 and the operational amplifier 1 are connected in parallel.

[0043] The voltage sampling circuit includes: a second operational amplifier circuit.

[0044] The second operational amplifier circuit includes a resistor R15, a resistor R16, a resistor R14 and an operational amplifier 2. The resistor R15 and the resistor R16 are connected to the input end of the operational amplifier 2, and the resistor R14 and the operational amplifier 2 are connected in parallel.

[0045] The present invention includes an overcurrent protection circuit consisting of a comparator circuit. The current sampling voltage is fed to the comparator's non-inverting input. The comparator's inverting input is set to a threshold value via a voltage divider circuit. When the current exceeds the threshold, the comparator's output level flips from high to low. The DSP control chip recognizes the OCP signal and shuts down the Q5 MOS transistor.

[0046] One end of the overcurrent protection circuit is connected to the current sampling circuit, and the other end is connected to the main control chip DSP.

[0047] The overcurrent protection circuit includes: a comparator circuit;

[0048] The non-inverting input terminal of the comparator circuit is connected to the current sampling circuit;

[0049] The inverting input terminal of the comparator circuit is connected to the voltage divider circuit;

[0050] The output end of the comparator circuit is connected to the main control chip DSP.

[0051] The output end of the comparator circuit is also connected to the MOS transistor Q6.

[0052] Preferably, Figure 6 As shown, the comparator circuit includes a resistor R6, a resistor R8, a resistor R20, a resistor R18, a resistor R12, a resistor R11, a transistor Q6, and an operational amplifier 3; the resistor R6, the resistor R8, and the resistor R20 are connected to the input end of the operational amplifier 3, and the resistor R18, the resistor R12, the resistor R11, and the transistor Q6 are connected to the output end of the operational amplifier 3.

[0053] The emitter of transistor Q6 is connected to the drive isolation optocoupler U1 to block the drive signal of MOS Q5, thereby disconnecting the battery port from the inverter DC / DC, thereby protecting the inverter. The collector of transistor Q6 is grounded.

[0054] The present application provides a battery port protection circuit for an energy storage inverter, which can reliably issue an alarm and disconnect the main power circuit for reverse connection and short circuit of the battery port, ensuring the safety and reliability of the inverter. The circuit scheme is relatively simple and easy to implement.

[0055] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0056] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0057] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units described is merely a logical function division. In actual implementation, other division methods may be used, such as combining or integrating multiple units or components into another device, or ignoring or not performing some features.

[0058] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0059] Although the present application is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and variations based on the above content. Therefore, all such substitutions, improvements and variations are included in the spirit and scope of the appended claims.

Claims

1. A battery port protection circuit for an energy storage inverter, characterized in that: The protection circuit includes: MOS tube Q5, current sampling circuit, voltage sampling circuit, and overcurrent protection circuit; The source of the MOS tube Q5 is connected to the battery port BAT+, and the drain is connected to the input electrolytic capacitor C1+ and the DC / DC input+ terminal; One end of the current sampling circuit is connected to the battery port BAT-, and the other end is connected to the main control chip DSP; the main control chip DSP is also connected to the MOS tube Q5; The voltage sampling circuit is connected to the battery port BAT+ and the battery port BAT-; One end of the overcurrent protection circuit is connected to the current sampling circuit, and the other end is connected to the main control chip DSP.

2. The energy storage inverter battery port protection circuit according to claim 1, characterized in that: The current sampling circuit includes: Current sampling resistor R2 and first operational amplifier circuit; The current sampling resistor R2 is connected to the battery port BAT-; The first operational amplifier circuit is connected in parallel with the current sampling resistor R2.

3. The energy storage inverter battery port protection circuit according to claim 2, characterized in that: The first operational amplifier circuit includes a resistor R5, a resistor R9, a resistor R4 and an operational amplifier 1; the resistor R5 and the resistor R9 are connected to the input end of the operational amplifier 1, and the resistor R4 and the operational amplifier 1 are connected in parallel.

4. The energy storage inverter battery port protection circuit according to claim 1, characterized in that: The voltage sampling circuit includes: a second operational amplifier circuit.

5. The energy storage inverter battery port protection circuit according to claim 4, characterized in that: The second operational amplifier circuit includes a resistor R15, a resistor R16, a resistor R14 and an operational amplifier 2. The resistor R15 and the resistor R16 are connected to the input end of the operational amplifier 2, and the resistor R14 and the operational amplifier 2 are connected in parallel.

6. The energy storage inverter battery port protection circuit according to claim 1, characterized in that: The overcurrent protection circuit includes: a comparator circuit; The non-inverting input terminal of the comparator circuit is connected to the current sampling circuit; The inverting input terminal of the comparator circuit is connected to the voltage divider circuit.

7. The energy storage inverter battery port protection circuit according to claim 6, characterized in that: The output end of the comparator circuit is connected to the main control chip DSP.

8. The energy storage inverter battery port protection circuit according to claim 6, characterized in that: The output end of the comparator circuit is also connected to the MOS transistor Q6.

9. The energy storage inverter battery port protection circuit according to claim 6, characterized in that: The comparator circuit includes a resistor R6, a resistor R8, a resistor R20, a resistor R18, a resistor R12, a resistor R11, a transistor Q6, and an operational amplifier 3; the resistor R6, the resistor R8, and the resistor R20 are connected to the input end of the operational amplifier 3, and the resistor R18, the resistor R12, the resistor R11, and the transistor Q6 are connected to the output end of the operational amplifier 3.

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