Energy storage inverter bus anti-pass protection circuit

Abstract

The application discloses a storage inverter bus anti-through protection circuit, which comprises a voltage division branch connected in parallel with the bus and a comparator group connected with the voltage division branch, the voltage division branch comprises resistors R1 and R2 and a voltage division grounding point, the comparator group comprises a supply voltage VCC, a first comparator U1 and a second comparator U2, the supply voltage VCC is provided with a voltage division grounding branch, the voltage division grounding branch is provided with resistors R3 and R4 and a voltage division grounding connection point, the output end of the first comparator U1 is connected with a Busk switch tube through a diode D2, and the output end of the second comparator U2 is connected with a Boost switch tube through a diode D1. The application compares and controls the driving ends of the Buck switch tube and the Boost switch tube through the anti-through bus voltage division index monitoring, thereby meeting the high-efficiency anti-through protection requirement. The application can realize surge protection, quickly responds when the anti-through bus voltage sharply drops, reduces the occurrence of the overvoltage damage of the comparator, and is safer in operation. The application can provide stable anti-through protection when the control software is abnormal or the driving end is abnormal.

Description

TECHNICAL FIELD

[0001] The application relates to a storage inverter bus anti-through protection circuit and belongs to the technical field of anti-DC protection. BACKGROUND

[0002] A Buck-Boost step-up and step-down circuit is used in DC / DC conversion between a battery and a bus for the convenience of battery charging and discharging operation. The inductance of the circuit exists as a power inductance at the battery end, and does not exist at the DC bus end. As a result, the Buck switch tube and the Boost switch tube of the step-up and step-down circuit are simultaneously turned on under certain abnormal conditions, and the current rises extremely fast without the inductance on the circuit, so that protection cannot be realized.

[0003] The current protection control is realized through software, a dead zone is left on the software, or drive interlocking is realized on hardware, so that the circuit protection requirement is met, but the processing mode cannot realize protection in the case that control is abnormal or the drive end is damaged. SUMMARY

[0004] The application aims at solving the problems of the prior art, and provides a storage inverter bus anti-through protection circuit to solve the problem of stability caused by protection loopholes in traditional software control and drive interlocking design.

[0005] To achieve the above object, the application adopts the following technical scheme:

[0006] The storage inverter bus anti-through protection circuit comprises a Buck-Boost step-up and step-down circuit arranged between a bus and an inductor, the Buck-Boost step-up and step-down circuit comprises a Buck switch tube and a Boost switch tube connected in parallel between the bus and the inductor, the Buck switch tube is provided with a Buck drive signal end, the Boost switch tube is provided with a Boost drive signal end,

[0007] The storage inverter bus anti-through protection circuit comprises a voltage division branch connected in parallel with the bus and a comparator group connected with the voltage division branch,

[0008] The voltage division branch comprises resistors R1 and R2 connected in series, the comparator group comprises a power supply voltage VCC, a first comparator U1 and a second comparator U2, the power supply voltage VCC is provided with a voltage division ground branch, the voltage division ground branch is provided with resistors R3 and R4 connected in series, the voltage division branch comprises a voltage division connection point arranged between the resistor R1 and the resistor R2, and the voltage division ground branch comprises a voltage division ground connection point arranged between the resistor R3 and the resistor R4,

[0009] The output end of the first comparator U1 is connected with the Buck switch tube through a diode D2, the negative input end of the first comparator U1 is connected with the voltage division ground connection point, and the positive input end is connected with the voltage division connection point,

[0010] The output end of the second comparator U2 is connected with the Boost switch tube through a diode D1, the negative input end of the second comparator U2 is connected with the voltage division ground connection point, and the positive input end is connected with the voltage division connection point.

[0011] Preferably, a direct-current protection capacitor C1 is arranged on the voltage division branch, and the direct-current protection capacitor C1 is arranged between the resistor R1 and the Buck switch tube.

[0012] Preferably, the power supply voltage VCC is provided with a sampling protection parallel branch connected in parallel with the voltage division ground branch, and the protection parallel branch comprises resistors R5 and R6 connected in series,

[0013] The protection parallel branch comprises a sampling protection connection point arranged between the resistor R5 and the resistor R6, and the sampling protection connection point is connected with the voltage division connection point and the voltage division ground connection point respectively,

[0014] The sampling protection connection point is provided with a protection diode D3 between the resistor R5 and the resistor R6, and a protection diode D4 between the resistor R6.

[0015] The beneficial effects of the present application mainly include:

[0016] 1. The driving end control of the Buck switch tube and the Boost switch tube is realized by comparison and control of the through bus voltage division index, so that the high-efficiency through protection requirement is met.

[0017] 2. Surge protection can be realized, the comparator overvoltage damage is reduced, and the operation is safer. 3. Stable through protection can be provided when the control software is abnormal or the driving end is abnormal. BRIEF DESCRIPTION OF DRAWINGS

[0018] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:

[0019] Figure 1 It is a circuit diagram of the bus through protection circuit of the energy storage inverter of the present application.

[0020] Figure 2 It is a preferred embodiment circuit diagram of the bus through protection circuit of the energy storage inverter of the present application. DETAILED DESCRIPTION

[0021] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0022] The present application will be further described below in detail with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and are not a limitation on the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0023] The present application provides an energy storage inverter bus anti-through protection circuit, as shown in Figure 1 , which comprises a Buck-Boost step-up and step-down circuit arranged between the bus and the inductor, the Buck-Boost step-up and step-down circuit comprising a Buck switch tube and a Boost switch tube connected in parallel between the bus and the inductor, the Buck switch tube having a Buck drive signal end, and the Boost switch tube having a Boost drive signal end.

[0024] The conventional protection adopts software or drives the Buck switch tube and the Boost switch tube to be interlocked on the hardware, and when control abnormality or damage exists at the drive end, it cannot realize the through protection.

[0025] In the present application, as shown in Figure 1 and Figure 2 , the energy storage inverter bus anti-through protection circuit comprises a voltage division branch connected in parallel with the bus and a comparator set connected with the voltage division branch.

[0026] The voltage division branch comprises resistors R1 and R2 connected in series, and the comparator set comprises a supply voltage VCC, a first comparator U1 and a second comparator U2, the supply voltage VCC having a voltage division ground branch, the voltage division ground branch being provided with resistors R3 and R4 connected in series, the voltage division branch comprising a voltage division connection point arranged between the resistors R1 and R2, and the voltage division ground branch comprising a voltage division ground connection point arranged between the resistors R3 and R4.

[0027] The output end of the first comparator U1 is connected with the Buck switch tube through a diode D2, the negative input end of the first comparator U1 is connected with the voltage division ground connection point, and the positive input end of the first comparator U1 is connected with the voltage division connection point.

[0028] The output of the second comparator U2 is connected with the Boost switch tube through a diode D1, the negative input of the second comparator U2 is connected with the voltage division ground connection point, and the positive input is connected with the voltage division connection point.

[0029] Specific implementation is described as follows:

[0030] The voltage on both sides of the DC bus can be measured by the voltage division branch, the measured voltage is directly input into the comparator, the reference voltage is divided by the voltage division ground branch, and the comparator group is compared and operated to meet the control requirements of the switch tube.

[0031] More specifically, the resistors R1 and R2 in the voltage division branch are used for bus voltage division measurement, and the resistors R3 and R4 are used for reference voltage division.

[0032] When the BUS voltage meets the set value, the outputs of the two comparators are high, at this time, the driving signal is not affected, and the high and low levels are input into the corresponding levels at the driving signal end.

[0033] When the BUS voltage is lower than the set value, the first comparator U1 and the second comparator U2 will output low at the same time, at this time, no matter whether the driving signal end inputs high or low, it will be pulled to low through the diode, so that the driving signal end is deadlocked. The BUS voltage allowed to be turned on is determined by the supply voltage VCC and the resistors R3 and R4, so as to meet the compatibility between the protection speed and the working voltage allowed to work. The resistors R1 and R2 are used to adjust the voltage signal level of the input comparator, so as to adapt to the reference level and the common-mode input range of the operational amplifier.

[0034] In one specific embodiment, as shown in Figure 2 A direct current protection capacitor C1 is arranged on the voltage division branch, and the direct current protection capacitor C1 is arranged between the resistor R1 and the Buck switch tube.

[0035] When a voltage mutation occurs on the BUS voltage, the direct current protection capacitor C1 must have a discharge current, so as to form a voltage on the resistor R1. In this way, a current limiting resistor is realized, thereby meeting the protection requirements.

[0036] In one preferred embodiment, the supply voltage VCC is provided with a sampling protection parallel branch connected in parallel with the voltage division ground branch, and the protection parallel branch includes resistors R5 and R6 connected in series.

[0037] The protection parallel branch includes a sampling protection connection point arranged between the resistors R5 and R6, and the sampling protection connection point is connected with the voltage division connection point and the voltage division ground connection point respectively.

[0038] The sampling protection connection point is provided with a protection diode D3 between the resistor R5 and the resistor R6, and a protection diode D4 between the resistor R6.

[0039] Specifically, the sampling protection parallel branch plays a surge protection demand, which is composed of resistance R5, resistance R6, protection diode D3 and protection diode D4, which can limit the input level of the first comparator U1 and the second comparator U2 by clamping to avoid overvoltage damage to the comparator.

[0040] In the circuit as shown in Figure 2 , resistance R3 and resistance R4 form a protected reference level, and an input voltage below this level represents an excessive BUS voltage drop, which is identified as a straight-through pre-process, at which time the comparator output is low, which will directly pass through diode D1 and diode D2 to block the drive input.

[0041] Of course, the signal can be sent to the DSP through the level conversion circuit to inform the DSP of the occurrence of straight-through, so that the DSP stops sending the drive signal.

[0042] From the above description, it can be found that the energy storage inverter bus anti-through protection circuit controls the drive end of the Buck switch tube and the Boost switch tube through the comparison of the through bus voltage division index monitoring, thereby meeting the high-efficiency anti-through protection demand. It can realize surge protection, quickly respond when the through bus voltage drops, reduce the occurrence of comparator overvoltage damage, and run more safely. It can provide stable anti-through protection when the control software is abnormal or the drive end is abnormal.

[0043] The term "comprising" or any other similar word is intended to cover non-exclusive inclusion, so that the process, method, article or equipment / device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes the elements inherent to the process, method, article or equipment / device.

[0044] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

Claims

1. An anti-through protection circuit for a storage inverter bus, comprising a Buck-Boost circuit arranged between the bus and an inductor, the Buck-Boost circuit comprising a Buck switch and a Boost switch connected in parallel between the bus and the inductor, the Buck switch being provided with a Buck drive signal terminal, and the Boost switch being provided with a Boost drive signal terminal, characterized in that: the anti-through protection circuit comprises a voltage division branch connected in parallel with the bus, and a comparator set connected to the voltage division branch; the voltage division branch comprises a resistor R1 and a resistor R2 connected in series, and the comparator set comprises a supply voltage VCC, a first comparator U1, and a second comparator U2, the supply voltage VCC being provided with a voltage division ground branch, the voltage division ground branch being provided with a resistor R3 and a resistor R4 connected in series, the voltage division branch comprising a voltage division connection point arranged between the resistor R1 and the resistor R2, and the voltage division ground branch comprising a voltage division ground connection point arranged between the resistor R3 and the resistor R4; an output terminal of the first comparator U1 is connected to the Buck switch through a diode D2, a negative input terminal of the first comparator U1 is connected to the voltage division ground connection point, and a positive input terminal of the first comparator U1 is connected to the voltage division connection point; an output terminal of the second comparator U2 is connected to the Boost switch through a diode D1, a negative input terminal of the second comparator U2 is connected to the voltage division ground connection point, and a positive input terminal of the second comparator U2 is connected to the voltage division connection point.

2. The anti-through protection circuit for a storage inverter bus according to claim 1, characterized in that: the voltage division branch is provided with a direct current blocking capacitor C1, and the direct current blocking capacitor C1 is arranged between the resistor R1 and the Buck switch.

3. The anti-through protection circuit for a storage inverter bus according to claim 1, characterized in that: the supply voltage VCC is provided with a sampling protection parallel branch connected in parallel with the voltage division ground branch, the sampling protection parallel branch comprising a resistor R5 and a resistor R6 connected in series; the sampling protection parallel branch comprises a sampling protection connection point arranged between the resistor R5 and the resistor R6, the sampling protection connection point being connected to the voltage division connection point and the voltage division ground connection point respectively, and a protection diode D3 being arranged between the sampling protection connection point and the resistor R5, and a protection diode D4 being arranged between the sampling protection connection point and the resistor R6. ​ ​ ​

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