Circuit for eliminating virtual voltage of connection port between battery and inverter

Abstract

The utility model relates to the technical field of energy storage, and discloses a circuit for eliminating virtual voltage of a connection port of a battery and an inverter, the circuit comprises a battery, a PDU control system, an optical storage all-in-one machine inverter and a photovoltaic assembly, the battery is connected with the optical storage all-in-one machine inverter through the PDU control system, and the photovoltaic assembly is directly connected with the optical storage all-in-one machine inverter; and an inverter side positive and negative loop output port of the PDU control system is connected in series with a diode and a PTC thermistor. The reverse virtual voltage is consumed by designing the unilateral diode and the PTC resistor, so that the virtual voltage is eliminated fundamentally, the function of battery reverse connection protection is reserved, and the circuit is safer and more reliable.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, and particularly relates to a circuit for eliminating virtual voltage at the connection port between a battery and an inverter. Background Art

[0002] When a current battery is connected to an inverter of a photovoltaic energy storage integrated machine, due to the influence of the bus capacitors at the photovoltaic end and the inverter itself, the environment, etc., after the inverter is powered on, a reverse virtual voltage will be generated at the battery end interface of the inverter, and the value of this virtual voltage is affected by the number of connected photovoltaics and the environment. When the battery is connected to the inverter and the battery is powered on and started, since the battery generally has a reverse voltage protection function, after detecting the reverse virtual voltage at the port, the battery will misreport a reverse connection fault, resulting in the situation where the battery cannot be started.

[0003] Currently in the market, battery-side software is generally used to shield the virtual voltage or the virtual voltage is eliminated by optimizing the inverter, but both cannot completely avoid the existence of virtual voltage, and software shielding cancels the reverse connection protection of the battery. Once there is a real reverse connection situation, it is easy to damage the device, and there is a certain risk. Summary of the Utility Model

[0004] In view of this, the utility model provides a circuit for eliminating virtual voltage at the connection port between a battery and an inverter to solve the problem that the commonly used solutions for virtual voltage at the current battery end cannot completely avoid the existence of virtual voltage.

[0005] The utility model provides a circuit for eliminating virtual voltage at the connection port between a battery and an inverter. The circuit includes: a battery, a PDU control system, an inverter of a photovoltaic energy storage integrated machine, and a photovoltaic module. Among them,

[0006] The battery is connected to the inverter of the photovoltaic energy storage integrated machine through the PDU control system, and the photovoltaic module is directly connected to the inverter of the photovoltaic energy storage integrated machine;

[0007] A diode and a PTC thermistor are connected in series at the positive and negative circuit output ports on the inverter side of the PDU control system.

[0008] The circuit for eliminating virtual voltage at the connection port between a battery and an inverter provided by the utility model eliminates the virtual voltage fundamentally by designing a one-way diode and a PTC resistor to consume the reverse virtual voltage, and retains the reverse connection protection function of the battery, which is safer and more reliable.

[0009] In an optional embodiment, the diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side inside the PDU control system, where

[0010] The cathode of the diode is connected to the positive output terminal on the inverter side inside the PDU control system. The anode of the diode is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is connected to the negative output terminal on the inverter side inside the PDU control system.

[0011] By arranging the diode and the PTC thermistor inside the PDU control system, the integration degree of the PDU control system is improved, and the volume of the entire circuit is significantly reduced.

[0012] In an alternative embodiment, the diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side outside the PDU control system, where

[0013] The cathode of the diode is respectively connected to the positive output terminal on the inverter side outside the PDU control system and the positive input terminal of the inverter of the photovoltaic energy storage integrated machine. The anode of the diode is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is respectively connected to the negative output terminal on the inverter side outside the PDU control system and the negative input terminal of the inverter of the photovoltaic energy storage integrated machine.

[0014] By arranging the diode and the PTC thermistor outside the PDU control system, the transformation difficulty is reduced, and the production cost is lowered.

[0015] In an alternative embodiment, the PDU control system further includes: an air circuit breaker and a fuse, where

[0016] The first end of the air circuit breaker is connected to the positive input terminal on the battery side of the PDU control system. The second end of the air circuit breaker is connected to the negative input terminal on the battery side of the PDU control system. The third end of the air circuit breaker is connected to one end of the fuse. The fourth end of the air circuit breaker is connected to the negative output terminal on the inverter side of the PDU control system, and the other end of the fuse is connected to the positive output terminal on the inverter side of the PDU control system.

[0017] In an alternative embodiment, the air circuit breaker is a double-pole circuit breaker.

[0018] By using a double-pole circuit breaker, the functions of dual-channel input and dual-channel output can be achieved. The double-pole circuit breaker can realize more flexible electrical control, greatly improving the safety and reliability.

[0019] In an alternative embodiment, the PDU control system further includes: a current acquisition device. One end of the current acquisition device is connected to the fourth end of the air circuit breaker, and the other end of the current acquisition device is connected to the negative output terminal on the inverter side of the PDU control system.

[0020] In an alternative embodiment, the PDU control system further includes: a first relay and a second relay, wherein,

[0021] One end of the first relay is connected to the other end of the fuse, and the other end of the first relay is connected to the positive output terminal on the inverter side of the PDU control system;

[0022] One end of the second relay is connected to the other end of the current acquisition device, and the other end of the second relay is connected to the negative output terminal on the inverter side of the PDU control system.

[0023] In an alternative embodiment, the PDU control system further includes: a third relay and a resistor, wherein,

[0024] One end of the third relay is respectively connected to one end of the first relay and the other end of the fuse, and the other end of the third relay is connected to the other end of the first relay through the resistor. Description of the Drawings

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 is the basic framework diagram of the connection between the battery and the inverter according to the embodiment of the present invention;

[0027] Figure 2 is the implementation diagram of Solution 1 according to the embodiment of the present invention;

[0028] Figure 3 is the implementation diagram of Solution 2 according to the embodiment of the present invention;

[0029] Figure 4 is the schematic diagram of the current flow direction of the diode and PTC thermistor circuit according to the embodiment of the present invention;

[0030] Figure 5 is another schematic diagram of the current flow direction of the diode and PTC thermistor circuit according to the embodiment of the present invention;

[0031] Figure 6 is another schematic diagram of the current flow direction of the diode and PTC thermistor circuit according to the embodiment of the present invention. Detailed Embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0033] In the description of the present utility model, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can also be the communication inside two components. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0034] In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0035] Currently, the common solution for the virtual voltage problem at the battery terminal is achieved through software shielding at the battery terminal, that is, canceling the reverse voltage protection, or specifying the reverse voltage protection threshold within a certain range. The former has a high risk. Once a real voltage reverse connection occurs, it is very easy to cause device damage and there are relatively large safety hazards; the latter sets the threshold of the reverse voltage. Voltages lower than this threshold are defaulted to virtual voltages and the battery system can be used normally, while voltages higher than this threshold are judged as real voltages for reverse connection protection. This solution is safer than the former, but it is difficult to cover all scenarios when formulating the threshold, and the reverse virtual voltage at the inverter port is greatly affected by the environment, and there are still certain risks. Therefore, it is necessary to propose a solution that can solve the virtual voltage at the port after the battery and the inverter are connected, ensure the normal startup of the battery and still retain the reverse connection protection for the battery.

[0036] For this reason, the present utility model provides a circuit for eliminating the virtual voltage at the connection port between the battery and the inverter. The basic framework of the embodiments of the present utility model is as Figure 1As shown in the figure, the battery is connected to the inverter of the integrated photovoltaic and energy storage unit through the PDU control system, and the photovoltaic module is directly connected to the inverter of the integrated photovoltaic and energy storage unit. When the inverter of the integrated photovoltaic and energy storage unit starts, a reverse virtual voltage will be formed at the B2+ / B2- port of the inverter of the integrated photovoltaic and energy storage unit. When the battery starts, since the PDU control system is connected to the inverter of the integrated photovoltaic and energy storage unit, a reverse voltage will be detected at the P+ / P- port. After the battery detects the reverse voltage, it will misjudge it as a reverse connection fault, so the battery cannot start.

[0037] To solve the problem of virtual voltage at the ports after the battery and the inverter are connected, ensure the normal start of the battery and still retain the reverse connection protection function of the battery, the embodiment of the present utility model improves the basic framework of the connection between the battery and the inverter in Figure 1 The improvement is as follows: A diode and a PTC thermistor are connected in series at the output ports of the positive and negative circuits on the inverter side of the PDU control system. By connecting a diode and a PTC thermistor in series at the P+ / P- end of the PDU control system, the reverse virtual voltage at the port of the inverter is eliminated unidirectionally according to the one-way conduction property of the diode and the power consumption characteristics of the resistor. After the reverse virtual voltage is eliminated, the reverse connection protection function of the battery can still be retained.

[0038] A circuit for eliminating the virtual voltage at the connection port between the battery and the inverter provided by the present utility model fundamentally eliminates the virtual voltage by designing a one-way diode and a PTC resistor to consume the reverse virtual voltage, and retains the reverse connection protection function of the battery, which is safer and more reliable.

[0039] In an optional implementation manner, the improvement is specifically carried out as follows: Solution 1, improve the inside of the PDU control system. As Figure 2 shown, a diode and a PTC thermistor are connected in series between the output ports of the positive and negative circuits on the inverter side inside the PDU control system. Solution 2, improve the basic framework of the connection between the battery and the inverter, and connect a diode and a PTC thermistor in series between the output ports of the positive and negative circuits on the inverter side outside the PDU control system, that is, connect a diode and a PTC thermistor between the PDU control system and the inverter of the integrated photovoltaic and energy storage unit.

[0040] Specifically, when Solution 1 is adopted to improve the inside of the PDU control system, refer to Figure 2 for the implementation diagram of the solution. As Figure 2As shown in the figure, the diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side inside the PDU control system. Among them, the cathode of the diode D is connected to the positive output terminal P+ on the inverter side inside the PDU control system, the anode of the diode D is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is connected to the negative output terminal P- on the inverter side inside the PDU control system. By arranging the diode and the PTC thermistor inside the PDU control system, the integration degree of the PDU control system is improved, and the volume of the entire circuit is greatly reduced.

[0041] When the second solution is adopted to improve the outside of the PDU control system, see the solution implementation diagram Figure 3 . As Figure 3 shown in the figure, the diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side outside the PDU control system. Among them, the cathode of the diode D is respectively connected to the positive output terminal P+ on the inverter side outside the PDU control system and the positive input terminal B2+ of the inverter of the photovoltaic and energy storage integrated machine. The anode of the diode D is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is respectively connected to the negative output terminal P- on the inverter side outside the PDU control system and the negative input terminal B2- of the inverter of the photovoltaic and energy storage integrated machine. By arranging the diode and the PTC thermistor outside the PDU control system, the transformation difficulty is reduced and the production cost is lowered.

[0042] In the embodiment of the present utility model, taking Figure 2 the solution as an example, when the inverter of the photovoltaic and energy storage integrated machine starts and there is a reverse virtual voltage at the port, after the battery is connected to the inverter of the photovoltaic and energy storage integrated machine, as Figure 4 shown in the figure, the loop is preferentially conducted, and the reverse virtual voltage at the port of the inverter of the photovoltaic and energy storage integrated machine will be consumed by the PTC thermistor. After that, the battery starts. When it is detected that there is no reverse voltage at the P+ / P- terminal, the battery system starts normally. When the entire system enters normal operation, the voltage at the P+ / P- port is a positive voltage. Due to the one-way conduction of the diode D, at this time, as Figure 5 shown in the figure, the loop is in an open state, and at this time, this loop does not affect the normal operation of the overall system. When there is a real reverse connection situation in the system, that is, there is a real reverse voltage at the P+ / P- port, at this time, as Figure 6The circuit shown is conducting, but the real reverse voltage does not disappear. Therefore, the heat generation of the PTC thermistor gradually increases and the temperature begins to rise. Since the characteristic of the PTC thermistor is that its resistance increases with the increase of temperature, with the accumulation of heat, the resistance of the PTC thermistor increases, the current in this circuit gradually decreases, and the circuit gradually tends to be open, realizing the protection of this circuit. At this time, if the battery is started, the reverse voltage at the P+ / P- port will be detected and the battery will be protected, so that the battery cannot be started. The embodiment of the present utility model not only solves the problem of virtual voltage at the port where the inverter is connected to the battery, but also retains the protection function after the battery is truly reversely connected, effectively eliminating the virtual voltage problem, ensuring the normal start of the battery, and being very safe and reliable.

[0043] In an alternative embodiment, as Figure 2 and Figure 3 shown, the PDU control system further includes: an air circuit breaker QF and a fuse FU. Among them, the first end of the air circuit breaker QF is connected to the positive input terminal B1+ on the battery side of the PDU control system, the second end of the air circuit breaker QF is connected to the negative input terminal B1- on the battery side of the PDU control system, the third end of the air circuit breaker QF is connected to one end of the fuse FU, the fourth end of the air circuit breaker QF is connected to the negative output terminal P- on the inverter side of the PDU control system, and the other end of the fuse FU is connected to the positive output terminal P+ on the inverter side of the PDU control system.

[0044] Specifically, the air circuit breaker QF and the fuse FU are used to protect against faults such as short circuits, severe overloads, and undervoltages occurring in the circuit or electrical equipment. Among them, the air circuit breaker QF is a double-pole circuit breaker. By using a double-pole circuit breaker, the effects of dual-channel input and dual-channel output can be achieved. The double-pole circuit breaker can achieve more flexible electrical control, greatly improving safety and reliability.

[0045] In an alternative embodiment, as Figure 2 and Figure 3 shown, the PDU control system further includes: a current acquisition device. One end of the current acquisition device is connected to the fourth end of the air circuit breaker QF, and the other end of the current acquisition device is connected to the negative output terminal P- on the inverter side of the PDU control system.

[0046] Specifically, the current acquisition device is used to acquire the current flowing through the PDU control system.

[0047] In an alternative embodiment, as Figure 2 and Figure 3As shown, the PDU control system further includes: a first relay KM1 and a second relay KM2. Among them, one end of the first relay KM1 is connected to the other end of the fuse FU, and the other end of the first relay KM1 is connected to the positive output terminal P+ on the inverter side of the PDU control system; one end of the second relay KM2 is connected to the other end of the current acquisition device, and the other end of the second relay KM2 is connected to the negative output terminal P- on the inverter side of the PDU control system.

[0048] Specifically, the first relay KM1 and the second relay KM2 are used to control the conduction of the internal loop of the PDU control system.

[0049] In an alternative embodiment, as Figure 2 and Figure 3 shown, the PDU control system further includes: a third relay KM3 and a resistor R. Among them, one end of the third relay KM3 is respectively connected to one end of the first relay KM1 and the other end of the fuse FU, and the other end of the third relay KM3 is connected to the other end of the first relay KM1 through the resistor R.

[0050] Specifically, the series branch formed by the third relay KM3 and the resistor R is connected in parallel across the first relay KM1. The series branch formed by the third relay KM3 and the resistor R is provided as a bypass of the first relay KM1.

[0051] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A circuit for eliminating virtual voltage at the connection port between a battery and an inverter, characterized in that The circuit includes: a battery, a PDU control system, a PV energy storage integrated inverter, and PV modules. Among them, the battery is connected to the PV energy storage integrated inverter through the PDU control system, and the PV modules are directly connected to the PV energy storage integrated inverter; the positive and negative circuit output ports on the inverter side of the PDU control system are connected in series with a diode and a PTC thermistor.

2. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 1, characterized in that, The diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side inside the PDU control system. Among them, the cathode of the diode is connected to the positive output terminal on the inverter side inside the PDU control system, the anode of the diode is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is connected to the negative output terminal on the inverter side inside the PDU control system.

3. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 1, wherein The diode and the PTC thermistor are arranged between the positive and negative circuit output ports on the inverter side outside the PDU control system. Among them, the cathode of the diode is respectively connected to the positive output terminal on the inverter side outside the PDU control system and the positive input terminal of the PV energy storage integrated inverter, the anode of the diode is connected to one end of the PTC thermistor, and the other end of the PTC thermistor is respectively connected to the negative output terminal on the inverter side outside the PDU control system and the negative input terminal of the PV energy storage integrated inverter.

4. The circuit for eliminating the virtual voltage at the connection port between the battery and the inverter according to claim 2 or 3, characterized in that The PDU control system further includes: an air circuit breaker and a fuse. Among them, the first end of the air circuit breaker is connected to the positive input terminal on the battery side of the PDU control system, the second end of the air circuit breaker is connected to the negative input terminal on the battery side of the PDU control system, the third end of the air circuit breaker is connected to one end of the fuse, the fourth end of the air circuit breaker is connected to the negative output terminal on the inverter side of the PDU control system, and the other end of the fuse is connected to the positive output terminal on the inverter side of the PDU control system.

5. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 4, characterized in that, The air circuit breaker is a double-pole circuit breaker.

6. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 4, characterized in that, The PDU control system further includes: a current acquisition device. One end of the current acquisition device is connected to the fourth end of the air circuit breaker, and the other end of the current acquisition device is connected to the negative output terminal on the inverter side of the PDU control system.

7. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 6, characterized in that, The PDU control system further includes: a first relay and a second relay. Among them, one end of the first relay is connected to the other end of the fuse, and the other end of the first relay is connected to the positive output terminal on the inverter side of the PDU control system; one end of the second relay is connected to the other end of the current acquisition device, and the other end of the second relay is connected to the negative output terminal on the inverter side of the PDU control system.

8. The circuit for eliminating virtual voltage at the connection port between the battery and the inverter according to claim 7, characterized in that, The PDU control system further includes: a third relay and a resistor. Among them, one end of the third relay is respectively connected to one end of the first relay and the other end of the fuse, and the other end of the third relay is connected to the other end of the first relay through the resistor.

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