Relay control circuit and fault detection method

Abstract

The invention discloses a relay control circuit and a fault detection method, the relay control circuit comprises a plurality of input terminals connected with alternating current input and a plurality of output terminals connected with a converter, and the number of the input terminals is different from that of the output terminals; a plurality of switching units are arranged between the input terminal and the output terminal, and the switching units can switch the connection state of the input terminal and the output terminal; the relay control circuit has a plurality of operation modes, and under different operation modes, the connection states of the input terminal and the output terminal are different. Compared with the prior art, switching among multiple modes can be achieved through control of the switching unit, meanwhile, the corresponding voltage sampling module is matched, the fault state of the relay control circuit can be judged, a corresponding protection strategy is executed, and the reliability of the relay control circuit is improved.

Description

Technical Field

[0001] The present invention relates to new energy vehicles, in particular to a relay control circuit and a fault detection method. Background Art

[0002] With the rapid development of new energy vehicles, each automobile manufacturer has put forward the functional requirements for in-vehicle inverters (powering electrical devices through the three-hole socket inside the vehicle) and out-of-vehicle inverters (powering electrical devices through the discharge gun outside the vehicle). However, based on the requirements of in-vehicle and out-of-vehicle inverters, when designing the circuit of the on-vehicle charger, the number of relays will increase exponentially, resulting in an increase in cost and volume.

[0003] There are currently two widely used relay adhesion detection schemes. The first is to directly use relays with adhesion detection functions. These relays are large in size, high in cost, and limited in model, and are very restricted in actual applications. The second is to detect the adhesion of both paths of the relay through optocoupler isolation. The disadvantage is that it cannot detect the situation where only one path is adhered.

[0004] Therefore, how to design a relay control circuit and a fault detection method to solve the problems in the prior art that the increase in the number of relays leads to an increase in cost and volume, and the relay adhesion fault is difficult to detect is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the problem in the prior art that to meet the functional requirements of in-vehicle and out-of-vehicle inverters, the number of relays is increased, resulting in an increase in cost and volume, the present invention proposes a relay control circuit and a fault detection method.

[0006] The technical solution of the present invention is to propose a relay control circuit, including a plurality of input terminals connected to an AC input and a plurality of output terminals connected to a converter, and the number of the input terminals is different from that of the output terminals;

[0007] A plurality of switching units are arranged between the input terminals and the output terminals, and the switching units can switch the connection state between the input terminals and the output terminals;

[0008] The relay control circuit has a plurality of operating modes, and in different operating modes, the connection state between the input terminals and the output terminals is different.

[0009] Further, four input terminals are provided, which are respectively: a first input terminal, a second input terminal, a third input terminal, and a fourth input terminal;

[0010] Two output terminals are provided, which are respectively: a first output terminal and a second output terminal;

[0011] The switching unit includes a first resistor, a second resistor, a first normally open relay, a second normally open relay, a first relay, and a second relay;

[0012] The first end of the first normally open relay is connected to the first input terminal, and the second end of the first normally open relay is connected to the first output terminal;

[0013] The first end of the second normally open relay is connected to the third input terminal, and the second end of the second normally open relay is connected to the second output terminal;

[0014] The first end of the first relay is connected to one end of the first resistor, the other end of the first resistor is connected to the first input terminal, the second end of the first relay is connected to the second input terminal, and the third end of the first relay is connected to the first output terminal;

[0015] The first end of the second relay is connected to one end of the second resistor, the other end of the second resistor is connected to the third input terminal, the second end of the second relay is connected to the fourth input terminal, and the third end of the second relay is connected to the second output terminal.

[0016] Further, the relay control circuit has five operating modes, namely: charging mode, external vehicle discharging mode, internal vehicle discharging mode, both external and internal vehicle discharging mode, and charge-discharge mode;

[0017] When the relay control circuit operates in the charging mode, the first end and the third end of the first relay are conducted, and the first end and the third end of the second relay are conducted for pre-charging. When the pre-charging is completed, the first normally open relay and the second normally open relay are closed for charging;

[0018] When the relay control circuit operates in the external vehicle discharging mode, the first normally open relay and the second normally open relay are closed for discharging;

[0019] When the relay control circuit operates in the internal vehicle discharging mode, the second end and the third end of the first relay are conducted, and the second end and the third end of the second relay are conducted for discharging;

[0020] When the relay control circuit operates in the both external and internal vehicle discharging mode, the first normally open relay and the second normally open relay are closed, the second end and the third end of the first relay are conducted, and the second end and the third end of the second relay are conducted for discharging;

[0021] When the relay control circuit operates in the charge and discharge mode, the first terminal and the third terminal of the first relay are conducted, the first terminal and the third terminal of the second relay are conducted for pre-charging, and when the pre-charging is completed, the first normally open relay and the second normally open relay are closed for charging, the second terminal and the third terminal of the first relay are conducted, and the second terminal and the third terminal of the second relay are conducted for discharging.

[0022] The present invention also provides a fault detection method using the above relay control circuit, including:

[0023] Controlling the switching unit to switch the connection state between the input terminal and the output terminal;

[0024] Detecting the voltage parameters of the input terminal and the output terminal in different connection states;

[0025] Judging the fault type of the relay control circuit according to the voltage parameters.

[0026] Furthermore, the relay control circuit has eight fault types, and when the second terminal of the first relay is stuck, it is the first fault type;

[0027] When the second terminal of the second relay is stuck, it is the second fault type;

[0028] When the first terminal of the first relay is stuck, it is the third fault type;

[0029] When the first terminal of the second relay is stuck, it is the fourth fault type;

[0030] When the first normally open relay is stuck, it is the fifth fault type;

[0031] When the second normally open relay is stuck, it is the sixth fault type;

[0032] When the first normally open relay cannot be closed, it is the seventh fault type;

[0033] When the second normally open relay cannot be closed, it is the eighth fault type.

[0034] Furthermore, when the first terminal and the third terminal of the first relay are connected, and the first terminal and the third terminal of the second relay are connected, judging the fault type of the relay control circuit according to the voltage parameters includes:

[0035] Calculating the voltage difference between the first output terminal and the second input terminal, and the voltage difference between the second output terminal and the fourth input terminal;

[0036] When the voltage differences between the first output terminal and the second input terminal, and between the second output terminal and the fourth input terminal are both less than the first threshold voltage, it is determined as the first fault type and the second fault type;

[0037] When the voltage difference between the first output terminal and the second input terminal is less than the first threshold voltage, and the voltage difference between the second output terminal and the fourth input terminal is greater than the first threshold voltage, it is determined as the first fault type;

[0038] When the voltage difference between the first output terminal and the second input terminal is greater than the first threshold voltage, and the voltage difference between the second output terminal and the fourth input terminal is less than the first threshold voltage, it is determined as the second fault type.

[0039] Further, when the second terminal and the third terminal of the first relay are connected, and the second terminal and the third terminal of the second relay are connected, the fault types of the relay control circuit judged according to the voltage parameters include:

[0040] Calculate the voltage differences between the first output terminal and the first input terminal, between the first output terminal and the second input terminal, between the second output terminal and the third input terminal, and between the second output terminal and the fourth input terminal;

[0041] When the voltage differences between the first output terminal and the second input terminal, and between the second output terminal and the fourth input terminal are both greater than the first threshold voltage, it is determined as the third fault type and the fourth fault type;

[0042] When the voltage difference between the first output terminal and the second input terminal is greater than the first threshold voltage, and the voltage difference between the second output terminal and the fourth input terminal is less than the first threshold voltage, it is determined as the third fault type;

[0043] When the voltage difference between the first output terminal and the second input terminal is less than the first threshold voltage, and the voltage difference between the second output terminal and the fourth input terminal is greater than the first threshold voltage, it is determined as the fourth fault type;

[0044] When the voltage differences between the first output terminal and the first input terminal, and between the second output terminal and the third input terminal are both less than the first threshold voltage, it is determined as the fifth fault type and the sixth fault type;

[0045] When the voltage difference between the first output terminal and the first input terminal is less than the first threshold voltage, and the voltage difference between the second output terminal and the third input terminal is greater than the first threshold voltage, it is determined as the fifth fault type;

[0046] When the voltage difference between the first output terminal and the first input terminal is greater than the first threshold voltage and the voltage difference between the second output terminal and the third input terminal is less than the first threshold voltage, it is determined as the sixth fault type.

[0047] Further, when the first normally open relay and the second normally open relay are closed, and the second terminal and the third terminal of the first relay are connected, and the second terminal and the third terminal of the second relay are connected, the fault types of the relay control circuit judged according to the voltage parameters include:

[0048] Calculate the voltage difference between the first output terminal and the first input terminal and the voltage difference between the second output terminal and the third input terminal;

[0049] When both the voltage difference between the first output terminal and the first input terminal and the voltage difference between the second output terminal and the third input terminal are greater than the first threshold voltage, it is determined as the seventh fault type and the eighth fault type;

[0050] When the voltage difference between the first output terminal and the first input terminal is greater than the first threshold voltage and the voltage difference between the second output terminal and the third input terminal is less than the first threshold voltage, it is determined as the seventh fault type;

[0051] When the voltage difference between the first output terminal and the first input terminal is less than the first threshold voltage and the voltage difference between the second output terminal and the third input terminal is greater than the first threshold voltage, it is determined as the eighth fault type.

[0052] Further, when the first terminal and the third terminal of the first relay are connected, and the first terminal and the third terminal of the second relay are connected, the fault types of the relay control circuit judged according to the voltage parameters further include:

[0053] Calculate the voltage difference between the first output terminal and the first input terminal and the voltage difference between the second output terminal and the third input terminal;

[0054] When the voltage difference between the first output terminal and the first input terminal is greater than the second threshold voltage, it is determined as the first fault type;

[0055] When the voltage difference between the first output terminal and the first input terminal is less than the first threshold voltage, it is determined as the fifth fault type;

[0056] When the voltage difference between the second output terminal and the third input terminal is greater than the second threshold voltage, it is determined as the second fault type;

[0057] When the voltage difference between the second output terminal and the third input terminal is less than the first threshold voltage, it is determined as the sixth fault type.

[0058] Further, when the second terminal and the third terminal of the first relay are connected, and the second terminal and the third terminal of the second relay are connected, the method for determining the fault type of the relay control circuit according to the voltage parameter further includes:

[0059] Calculate the voltage difference between the first output terminal and the first input terminal, and the voltage difference between the second output terminal and the third input terminal;

[0060] When the voltage difference between the first output terminal and the first input terminal is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the third fault type;

[0061] When the voltage difference between the first output terminal and the first input terminal is less than the first threshold voltage, it is determined as the fifth fault type;

[0062] When the voltage difference between the second output terminal and the third input terminal is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the fourth fault type;

[0063] When the voltage difference between the second output terminal and the third input terminal is less than the first threshold voltage, it is determined as the sixth fault type.

[0064] Further, when the first normally open relay and the second normally open relay are closed, the second terminal and the third terminal of the first relay are connected, and the second terminal and the third terminal of the second relay are connected, the method for determining the fault type of the relay control circuit according to the voltage parameter further includes:

[0065] Calculate the voltage difference between the first output terminal and the first input terminal, and the voltage difference between the second output terminal and the third input terminal;

[0066] When the voltage difference between the first output terminal and the first input terminal is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the third fault type and the fourth fault type;

[0067] When the voltage difference between the second output terminal and the third input terminal is greater than the second threshold voltage, it is determined as the eighth fault type.

[0068] When the voltage difference between the second output terminal and the third input terminal is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the fourth fault type and the eighth fault type.

[0069] Further, it further includes: when the relay control circuit is in the first fault type or the second fault type, the relay control circuit is prohibited from operating in the in-vehicle discharge mode;

[0070] When the relay control circuit is in at least one of the third fault type, the fourth fault type, the fifth fault type, and the sixth fault type, the relay control circuit is prohibited from operating in the charging mode, the out-vehicle discharge mode, and the in-vehicle discharge mode;

[0071] When the relay control circuit is in the seventh fault type or the eighth fault type, the relay control circuit is prohibited from operating in the charging mode and the out-vehicle discharge mode.

[0072] Compared with the prior art, the present invention has at least the following beneficial effects:

[0073] 1. In the present invention, a plurality of switching units are provided, and the switching between the charging mode, the out-vehicle discharge mode, the in-vehicle discharge mode, the in-out vehicle discharge mode, and the charge-discharge mode is realized through the switching between the switching units, without increasing the number of relays at the cost, reducing the design cost and the volume of the device;

[0074] 2. In the present invention, through voltage detection, the fault detection of the relay control circuit can be realized, and corresponding protection strategies are set, improving the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0076] Figure 1 It is a circuit topology schematic diagram of the relay control circuit proposed by the present invention;

[0077] Figure 2 It is a logic schematic diagram of relay fault judgment under the first embodiment of the present invention;

[0078] Figure 3 It is a logic schematic diagram of relay fault judgment under the second embodiment of the present invention;

[0079] Figure 4 It is a protection action schematic diagram under different fault types of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0080] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0081] Thus, a feature pointed out in this specification will be used to illustrate one of the features of one embodiment of the present invention, rather than implying that each embodiment of the present invention must have the feature described. In addition, it should be noted that this specification describes many features. Although some features may be combined to show possible system designs, these features can also be used in other combinations not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0082] The principle and structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0083] To achieve the in-vehicle inversion and out-of-vehicle inversion functions of an on-vehicle charger, the technical solutions in the prior art mostly involve adding the setting of relays, but this setting method will lead to an increase in cost and volume.

[0084] Based on the above problems, the present invention proposes a relay control circuit, which includes a plurality of input terminals connected to an AC input and a plurality of output terminals connected to a converter, and the number of input terminals and output terminals is different;

[0085] A plurality of switching units are arranged between the input terminals and the output terminals, and the switching units can switch the connection state between the input terminals and the output terminals;

[0086] The relay control circuit has a plurality of operating modes, and the connection state between the input terminals and the output terminals is different in different operating modes.

[0087] Among them, the above switching unit is a relay and a resistor connected to the relay. From the above settings, it can be seen that the main idea of the present invention is to change the connection state between the input terminals and the output terminals through the switching unit, so that the relay control circuit works in different operating modes. Compared with the prior art, the above settings can save a large number of relay settings, thereby reducing the cost and volume of the product.

[0088] Please refer to Figure 1 , in the present invention, 2. Four input terminals are provided, namely: the first input terminal L1, the second input terminal L2, the third input terminal N1, and the fourth input terminal N2;

[0089] Two output terminals are provided, namely: the first output terminal L and the second output terminal N;

[0090] The switching unit includes a first resistor RL , the second resistor R N , the first normally open relay S L1 , the second normally open relay S N1 , the first relay S L2 , the second relay S N2 ;

[0091] The first end of the first normally open relay S L1 is connected to the first input terminal L1, and the second end of the first normally open relay S L1 is connected to the first output terminal L;

[0092] The first end of the second normally open relay S N1 is connected to the third input terminal N1, and the second end of the second normally open relay S N1 is connected to the second output terminal N;

[0093] The first end of the first relay S L2 is connected to one end of the first resistor R L , the other end of the first resistor R L is connected to the first input terminal L1, and the second end of the first relay S L2 is connected to the second input terminal L2, and the third end of the first relay S L2 is connected to the first output terminal L;

[0094] The first end of the second relay S N2 is connected to one end of the second resistor R N , the other end of the second resistor R N is connected to the third input terminal N1, and the second end of the second relay S N2 is connected to the fourth input terminal N2, and the third end of the second relay S N2 is connected to the second output terminal N.

[0095] Based on the above structure, the relay control circuit in the present invention has five operating modes, namely: charging mode, external discharging mode, internal discharging mode, external and internal discharging mode, charge and discharge mode;

[0096] When the relay control circuit operates in the charging mode, the first end and the third end of the first relay S L2 are conducted, and the first end and the third end of the second relay S N2 are conducted for pre-charging. At this time, the external AC voltage enters from the first input terminal L1 and the third input terminal N1, and the bus capacitor in the converter connected to the first output terminal L and the second output terminal N is pre-charged. When the pre-charging is completed, the first normally open relay S L1 and the second normally open relay S N1 are closed for charging;

[0097] When the relay control circuit operates in the external discharge mode, the first normally open relay S L1 and the second normally open relay S N1 are closed for discharging. At this time, the voltages in the converter enter from the first output terminal L and the second output terminal N respectively, and pass through the first normally open relay S L1 and the second normally open relay S N1 respectively, and then are output from the first input terminal L1 and the third input terminal N1 for discharging;

[0098] When the relay control circuit operates in the internal discharge mode, the second terminal and the third terminal of the first relay S L2 are conducted, and the second terminal and the third terminal of the second relay S N2 are conducted for discharging. At this time, the voltages in the converter enter from the first output terminal L and the second output terminal N respectively, and pass through the first relay S L2 and the second relay S N2 respectively, and then are output from the second input terminal L2 and the fourth input terminal N2 for discharging;

[0099] When the relay control circuit operates in the internal and external discharge mode, the first normally open relay S L1 and the second normally open relay S N1 are closed, the second terminal and the third terminal of the first relay S L2 are conducted, and the second terminal and the third terminal of the second relay S N2 are conducted for discharging. At this time, the voltages in the converter enter from the first output terminal L and the second output terminal N respectively, and pass through the first normally open relay S L1 , the second normally open relay S N1 , the first relay S L2 , the second relay S N2 respectively, and then are output from the first output terminal L1, the third output terminal N1, the second input terminal L2, and the fourth input terminal N2 for discharging;

[0100] When the relay control circuit operates in the charge and discharge mode, the first terminal and the third terminal of the first relay S L2 are conducted, and the first terminal and the third terminal of the second relay S N2 are conducted for pre-charging. At this time, the external AC voltage enters from the first input terminal L1 and the third input terminal N1 to realize the pre-charging of the first output terminal L and the second output terminal N. When the pre-charging is completed, the first normally open relay S L1 and the second normally open relay S N1 are closed for charging, the second terminal and the third terminal of the first relay S L2 are conducted, and the second terminal and the third terminal of the second relay S N2The second end and the third end are conducted for discharging. At this time, the external AC voltage enters from the first input terminal L1 and the third input terminal N1 respectively, and passes through the first normally open relay S L1 , the second normally open relay S N1 , the first relay S L2 , the second relay S N2 respectively, and then charges for the first output terminal L1, the third output terminal N1, the second input terminal L2, and the fourth input terminal N2;

[0101] Among them, the above-mentioned in-vehicle discharge mode and out-of-vehicle discharge mode are also the in-vehicle inversion mode and out-of-vehicle inversion mode pointed out in the background technology. The in-vehicle and out-of-vehicle discharge modes are the in-vehicle inversion mode and out-of-vehicle inversion mode simultaneously. The charge and discharge mode is the charging mode and the in-vehicle inversion mode simultaneously. The first end of the first relay S L2 is the end labeled 1 of the first relay S Figure 1 in the appendix, the second end of the first relay S L2 is the end labeled 2 of the first relay S L2 in the appendix, the third end of the first relay S Figure 1 is the fixed end of the first relay S L2 in the appendix. The first end of the second relay S L2 is the end labeled 1 of the second relay S Figure 1 in the appendix, the second end of the second relay S L2 is the end labeled 2 of the second relay S N2 in the appendix, the third end of the second relay S Figure 1 is the fixed end of the second relay S N2 in the appendix. The first end of the second relay S N2 is the end labeled 1 of the second relay S Figure 1 in the appendix, the second end of the second relay S N2 is the end labeled 2 of the second relay S N2 in the appendix, the third end of the second relay S Figure 1 is the fixed end of the second relay S N2 in the appendix.

[0102] Based on the above settings, it can be seen that the present invention can realize the switching between the charging mode, the out-of-vehicle discharge mode, the in-vehicle discharge mode, the in-vehicle and out-of-vehicle discharge mode, and the charge and discharge mode through the switching between the switching units, without increasing the number of relays at the cost, reducing the design cost and the volume of the device.

[0103] Based on the above relay control circuit, the present invention also proposes a fault detection method, which includes:

[0104] Controlling the switching unit to switch the connection state of the input terminal and the output terminal;

[0105] Detecting the voltage parameters of the input terminal and the output terminal in different connection states;

[0106] Judge the fault type of the relay control circuit according to the voltage parameter.

[0107] Specifically, there are eight fault types in the relay control circuit of the present invention, which are respectively:

[0108] When the second terminal of the first relay S L2 is adhered, it is the first fault type;

[0109] When the second terminal of the second relay S N2 is adhered, it is the second fault type;

[0110] When the first terminal of the first relay S L2 is adhered, it is the third fault type;

[0111] When the first terminal of the second relay S N2 is adhered, it is the fourth fault type;

[0112] When the first normally open relay S L1 is adhered, it is the fifth fault type;

[0113] When the second normally open relay S N1 is adhered, it is the sixth fault type;

[0114] When the first normally open relay S L1 cannot be closed, it is the seventh fault type;

[0115] When the second normally open relay S N1 cannot be closed, it is the eighth fault type.

[0116] Based on the above fault detection method, the corresponding judgment logic is given in the first embodiment of the present invention, specifically:

[0117] When the first terminal and the third terminal of the first relay S L2 are connected, and the first terminal and the third terminal of the second relay S N2 are connected, a voltage is generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit judged according to the voltage parameter include:

[0118] Calculate the voltage difference between the first output terminal L and the second input terminal L2, and the voltage difference between the second output terminal N and the fourth input terminal N2;

[0119] When the voltage difference between the first output terminal L and the second input terminal L2, and the voltage difference between the second output terminal N and the fourth input terminal N2 are both less than the first threshold voltage, it is determined as the first fault type and the second fault type;

[0120] When the voltage difference between the first output terminal L and the second input terminal L2 is less than the first threshold voltage, and the voltage difference between the second output terminal N and the fourth input terminal N2 is greater than the first threshold voltage, it is determined as the first fault type;

[0121] When the voltage difference between the first output terminal L and the second input terminal L2 is greater than the first threshold voltage, and the voltage difference between the second output terminal N and the fourth input terminal N2 is less than the first threshold voltage, it is determined as the second fault type.

[0122] When the second terminal and the third terminal of the first relay S L2 are connected, and the second terminal and the third terminal of the second relay S N2 are connected, voltages are generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit are judged according to the voltage parameters, including:

[0123] Calculate the voltage differences between the first output terminal L and the first input terminal L1, between the first output terminal L and the second input terminal L2, between the second output terminal N and the third input terminal N1, and between the second output terminal N and the fourth input terminal N2;

[0124] When the voltage differences between the first output terminal L and the second input terminal L2 and between the second output terminal N and the fourth input terminal N2 are both greater than the first threshold voltage, it is determined as the third fault type and the fourth fault type;

[0125] When the voltage difference between the first output terminal L and the second input terminal L2 is greater than the first threshold voltage, and the voltage difference between the second output terminal N and the fourth input terminal N2 is less than the first threshold voltage, it is determined as the third fault type;

[0126] When the voltage difference between the first output terminal L and the second input terminal L2 is less than the first threshold voltage, and the voltage difference between the second output terminal N and the fourth input terminal N2 is greater than the first threshold voltage, it is determined as the fourth fault type;

[0127] When the voltage differences between the first output terminal L and the first input terminal L1 and between the second output terminal N and the third input terminal N1 are both less than the first threshold voltage, it is determined as the fifth fault type and the sixth fault type;

[0128] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the first threshold voltage, and the voltage difference between the second output terminal N and the third input terminal N1 is greater than the first threshold voltage, it is determined as the fifth fault type;

[0129] When the voltage difference between the first output terminal L and the first input terminal L1 is greater than the first threshold voltage, and the voltage difference between the second output terminal N and the third input terminal N1 is less than the first threshold voltage, it is determined as the sixth fault type.

[0130] When the first normally open relay S L1 and the second normally open relay S N1 are closed, and the second terminal and the third terminal of the first relay S L2 are connected, and the second terminal and the third terminal of the second relay S N2 are connected, voltages are generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit are judged according to the voltage parameters, including:

[0131] Calculate the voltage difference between the first output terminal L and the first input terminal L1, and the voltage difference between the second output terminal N and the third input terminal N1;

[0132] When both the voltage difference between the first output terminal L and the first input terminal L1 and the voltage difference between the second output terminal N and the third input terminal N1 are greater than the first threshold voltage, it is determined as the seventh fault type and the eighth fault type;

[0133] When the voltage difference between the first output terminal L and the first input terminal L1 is greater than the first threshold voltage, and the voltage difference between the second output terminal N and the third input terminal N1 is less than the first threshold voltage, it is determined as the seventh fault type;

[0134] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the first threshold voltage, and the voltage difference between the second output terminal N and the third input terminal N1 is greater than the first threshold voltage, it is determined as the eighth fault type.

[0135] Please refer to Figure 1 , denote the voltage at the above-mentioned first output terminal L as V1, the voltage at the second input terminal L2 as V2, the voltage at the first input terminal L1 as V3, the voltage at the second output terminal N as V4, the voltage at the third input terminal N1 as V5, the voltage at the fourth input terminal N2 as V6, and denote the connection of the first terminal and the third terminal of the first relay S L2 and the second relay S N2 as closed 1, denote the connection of the second terminal and the third terminal of the first relay S L2 and the second relay S N2 as closed 2, and denote the first threshold voltage as threshold 1, then the fault judgment logic diagram as shown in Figure 2 can be obtained.

[0136] Here, the voltages at each input terminal and output terminal can be obtained by setting corresponding voltage sampling modules.

[0137] Based on the above fault detection method, the corresponding judgment logic is also given in the second embodiment of the present invention, specifically as follows:

[0138] When the first end and the third end of the first relay S L2 are connected, and the first end and the third end of the second relay S N2 are connected, voltages are generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit judged according to the voltage parameters also include:

[0139] Calculate the voltage difference between the first output terminal L and the first input terminal L1, and the voltage difference between the second output terminal N and the third input terminal N1;

[0140] When the voltage difference between the first output terminal L and the first input terminal L1 is greater than the second threshold voltage, it is determined as the first fault type;

[0141] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the first threshold voltage, it is determined as the fifth fault type;

[0142] When the voltage difference between the second output terminal N and the third input terminal N1 is greater than the second threshold voltage, it is determined as the second fault type;

[0143] When the voltage difference between the second output terminal N and the third input terminal N1 is less than the first threshold voltage, it is determined as the sixth fault type.

[0144] When the second end and the third end of the first relay S L2 are connected, and the second end and the third end of the second relay S N2 are connected, voltages are generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit judged according to the voltage parameters also include:

[0145] Calculate the voltage difference between the first output terminal L and the first input terminal L1, and the voltage difference between the second output terminal N and the third input terminal N1;

[0146] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the third fault type;

[0147] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the first threshold voltage, it is determined as the fifth fault type;

[0148] When the voltage difference between the second output terminal N and the third input terminal N1 is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the fourth fault type;

[0149] When the voltage difference between the second output terminal N and the third input terminal N1 is less than the first threshold voltage, it is determined as the sixth fault type.

[0150] When the first normally open relay S L1 and the second normally open relay S N1 are closed, and the second terminal and the third terminal of the first relay S L2 are connected, and the second terminal and the third terminal of the second relay S N2 are connected, voltages are generated at the first output terminal L and the second output terminal N through the inversion function of the on-vehicle charger. At this time, the fault types of the relay control circuit determined according to the voltage parameters also include:

[0151] Calculate the voltage difference between the first output terminal L and the first input terminal L1, and the voltage difference between the second output terminal N and the third input terminal N1;

[0152] When the voltage difference between the first output terminal L and the first input terminal L1 is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the third fault type and the fourth fault type;

[0153] When the voltage difference between the second output terminal N and the third input terminal N1 is greater than the second threshold voltage, it is determined as the eighth fault type.

[0154] When the voltage difference between the second output terminal N and the third input terminal N1 is less than the second threshold voltage and greater than the first threshold voltage, it is determined as the fourth fault type and the eighth fault type.

[0155] Please refer to Figure 1 , denote the voltage at the above-mentioned first output terminal L as V1, the voltage at the second input terminal L2 as V2, the voltage at the first input terminal L1 as V3, the voltage at the second output terminal N as V4, the voltage at the third input terminal N1 as V5, the voltage at the fourth input terminal N2 as V6, denote the connection of the first terminal and the third terminal of the first relay S L2 and the second relay S N2 as closed 1, denote the connection of the second terminal and the third terminal of the first relay S L2 and the second relay S N2 as closed 2, denote the first threshold voltage as threshold 1, and the second threshold voltage as threshold 2, then the fault judgment logic diagram as shown in Figure 3 can be obtained.

[0156] Here, the voltages at each input terminal and output terminal can be obtained by setting corresponding voltage sampling modules.

[0157] Comparing the solutions of the first embodiment and the second embodiment above, it can be seen that the solution of the second embodiment reduces two-way voltage sampling compared to the solution of the first embodiment, but adds a judgment threshold, that is, the judgment of the second threshold voltage. Here, the first threshold voltage is greater than zero but close to zero, and the second threshold voltage is less than the voltage generated on the first output terminal L and the second output terminal N, and is much greater than the first threshold voltage.

[0158] The above two embodiments can be selected according to the actual situation, and both can realize the detection and judgment of relay faults.

[0159] Based on the above fault types, the present invention also gives corresponding control strategies for different fault types, which are respectively that when the relay control circuit is in the first fault type or the second fault type, the relay control circuit is prohibited from operating in the in-vehicle discharge mode;

[0160] When the relay control circuit is in at least one of the third fault type, the fourth fault type, the fifth fault type, and the sixth fault type, the relay control circuit is prohibited from operating in the charging mode, the out-of-vehicle discharge mode, and the in-vehicle discharge mode;

[0161] When the relay control circuit is in the seventh fault type or the eighth fault type, the relay control circuit is prohibited from operating in the charging mode and the out-of-vehicle discharge mode.

[0162] Among them, the above out-of-vehicle discharge mode is denoted as the out-of-vehicle inversion mode, the in-vehicle discharge mode is denoted as the in-vehicle inversion mode, the mode that can be executed is denoted as "√", the mode that is prohibited from being executed is denoted as "×", the first fault type is denoted as fault one, the second fault type is denoted as fault two, the third fault type is denoted as fault three, the fourth fault type is denoted as fault four, the fifth fault type is denoted as fault five, the sixth fault type is denoted as fault six, the seventh fault type is denoted as fault seven, and the eighth fault type is denoted as fault eight. Then, the protection action schematic diagram as shown in Figure 2 can be obtained.

[0163] Based on the above fault detection and the corresponding protection strategy, it can be seen that in the present invention, through voltage detection, the fault detection of the relay control circuit can be realized, and at the same time, corresponding protection strategies are set, which improves the reliability of the product.

[0164] In summary, the present invention has at least the following beneficial effects:

[0165] 1. In the present invention, a plurality of switching units are provided, and the switching between the charging mode, the out-of-vehicle discharge mode, the in-vehicle discharge mode, the in-vehicle and out-of-vehicle discharge mode, and the charge and discharge mode is realized through the switching between the switching units, without increasing the number of relays at the cost, reducing the design cost and the volume of the device;

[0166] 2. In the present invention, through voltage detection, the fault detection of the relay control circuit can be achieved, and corresponding protection strategies are set, improving the reliability of the product.

[0167] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A relay control circuit, characterized in that: comprising a plurality of input terminals connected to an AC input, and a plurality of output terminals connected to a converter, wherein the number of the input terminals is different from the number of the output terminals; A plurality of switching units are provided between the input terminal and the output terminal, and the switching units can switch the connection state between the input terminal and the output terminal; The relay control circuit has a plurality of operation modes, and in different operation modes, the connection state between the input terminal and the output terminal is different.

2. The relay control circuit according to claim 1, characterized in that: The input terminals are provided with four, namely: a first input terminal (L1), a second input terminal (L2), a third input terminal (N1), and a fourth input terminal (N2); The output terminals are provided with two, namely: a first output terminal (L) and a second output terminal (N); The switching unit includes a first resistor (R L )、Second resistor (R N )、First normally open relay (S L1 )、Second normally open relay (S N1 )、First relay (S L2 )、Second relay (S N2 ); The first normally open relay (S L1 ) is connected to the first input terminal (L1), the first normally open relay (S L1 ), the second end of which is connected to the first output terminal (L); The second normally open relay (S N1 ) is connected to the third input terminal (N1), the second normally open relay (S N1 ) is connected to the second output terminal (N); The first relay (S L2 ) is connected to the first resistor (R L ) at one end, the first resistor (R L ) is connected to the first input terminal (L1), the first relay (S L2 ) is connected to the second input terminal (L2), the first relay (S L2 ) has a third end connected to the first output terminal (L); The second relay (S N2 ) is connected to the first end of the second resistor (R N ) one end, the second resistor (R N ) is connected to the third input terminal (N1), the second relay (S N2 ) is connected to the fourth input terminal (N2), the second relay (S N2 ) is connected to the second output terminal (N).

3. The relay control circuit according to claim 2, characterized in that: The relay control circuit has five operation modes, namely: charging mode, off-vehicle discharge mode, on-vehicle discharge mode, on-vehicle and off-vehicle discharge mode, and charging and discharging mode; When the relay control circuit operates in the charging mode, the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end for pre-charging, and when the pre-charging is completed, the first normally open relay (S L1 ) and the second normally open relay (S N1 ) is closed for charging; When the relay control circuit operates in the off-vehicle discharge mode, the first normally open relay (S L1 ) and the second normally open relay (S N1 ) is closed for discharge; When the relay control circuit operates in the in-vehicle discharge mode, the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end for discharge; When the relay control circuit operates in the in-vehicle or out-of-vehicle discharge mode, the first normally open relay (S L1 ) and the second normally open relay (S N1 ) is closed, the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end for discharge; When the relay control circuit operates in the charge and discharge mode, the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end for pre-charging, and when the pre-charging is completed, the first normally open relay (S L1 ) and the second normally open relay (S N1 ) is closed for charging, the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end for discharge.

4. A fault detection method using the relay control circuit as claimed in claim 2 or 3, characterized in that: include: Controlling the switching unit to switch the connection state between the input terminal and the output terminal; detecting voltage parameters of the input terminal and the output terminal in different connection states; The fault type of the relay control circuit is determined according to the voltage parameter.

5. The fault detection method according to claim 4, characterized in that: The relay control circuit has eight fault types, and when the first relay (S L2 ) is stuck at the second end, which is the first fault type; When the second relay (S N2 ) is stuck at the second end, which is the second fault type; When the first relay (S L2 ) is the third fault type when the first end is adhered; When the second relay (S N2 ) is stuck at the first end, which is the fourth fault type; When the first normally open relay (S L1 ) Adhesion is the fifth fault type; When the second normally open relay (S N1 ) Adhesion is the sixth fault type; When the first normally open relay (S L1 ) cannot be closed, which is the seventh fault type; When the second normally open relay (S N1 ) cannot be closed, which is the eighth fault type.

6. The fault detection method according to claim 5, characterized in that: When the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter includes: calculating a voltage difference between the first output terminal (L) and the second input terminal (L2), and a voltage difference between the second output terminal (N) and the fourth input terminal (N2); When the voltage difference between the first output terminal (L) and the second input terminal (L2), and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) are both less than a first threshold voltage, it is determined to be a first fault type and a second fault type; When the voltage difference between the first output terminal (L) and the second input terminal (L2) is less than a first threshold voltage, and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) is greater than the first threshold voltage, it is determined to be a first fault type; When the voltage difference between the first output terminal (L) and the second input terminal (L2) is greater than a first threshold voltage, and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) is less than the first threshold voltage, it is determined to be a second fault type.

7. The fault detection method according to claim 5, characterized in that: When the first relay (S L2 ) is connected to the third end, the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter includes: calculating a voltage difference between a first output terminal (L) and the first input terminal (L1), a voltage difference between the first output terminal (L) and the second input terminal (L2), a voltage difference between the second output terminal (N) and the third input terminal (N1), and a voltage difference between the second output terminal (N) and the fourth input terminal (N2); When the voltage difference between the first output terminal (L) and the second input terminal (L2), and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) are both greater than a first threshold voltage, it is determined to be a third fault type and a fourth fault type; When the voltage difference between the first output terminal (L) and the second input terminal (L2) is greater than a first threshold voltage, and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) is less than the first threshold voltage, it is determined to be a third fault type; When the voltage difference between the first output terminal (L) and the second input terminal (L2) is less than a first threshold voltage, and the voltage difference between the second output terminal (N) and the fourth input terminal (N2) is greater than the first threshold voltage, it is determined to be a fourth fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1), and the voltage difference between the second output terminal (N) and the third input terminal (N1) are both less than a first threshold voltage, it is determined to be a fifth fault type and a sixth fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than a first threshold voltage, and the voltage difference between the second output terminal (N) and the third input terminal (N1) is greater than the first threshold voltage, it is determined to be a fifth fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is greater than a first threshold voltage, and the voltage difference between the second output terminal (N) and the third input terminal (N1) is less than the first threshold voltage, it is determined to be a sixth fault type.

8. The fault detection method according to claim 5, characterized in that: When the first normally open relay (S L1 ) and the second normally open relay (S N1 ) is closed, the first relay (S L2 ) is connected to the third end, the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter includes: calculating a voltage difference between a first output terminal (L) and the first input terminal (L1), and a voltage difference between the second output terminal (N) and the third input terminal (N1); When the voltage difference between the first output terminal (L) and the first input terminal (L1), and the voltage difference between the second output terminal (N) and the third input terminal (N1) are both greater than a first threshold voltage, it is determined to be a seventh fault type and an eighth fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is greater than a first threshold voltage, and the voltage difference between the second output terminal (N) and the third input terminal (N1) is less than the first threshold voltage, it is determined to be a seventh fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than a first threshold voltage, and the voltage difference between the second output terminal (N) and the third input terminal (N1) is greater than the first threshold voltage, it is determined to be an eighth fault type.

9. The fault detection method according to claim 5, characterized in that: When the first relay (S L2 ) is connected to the third end, and the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter also includes: calculating a voltage difference between a first output terminal (L) and the first input terminal (L1), and a voltage difference between the second output terminal (N) and the third input terminal (N1); When the voltage difference between the first output terminal (L) and the first input terminal (L1) is greater than a second threshold voltage, determining it as a first fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than a first threshold voltage, determining that it is a fifth fault type; When the voltage difference between the second output terminal (N) and the third input terminal (N1) is greater than a second threshold voltage, it is determined to be a second fault type; When the voltage difference between the second output terminal (N) and the third input terminal (N1) is less than a first threshold voltage, it is determined to be a sixth fault type.

10. The fault detection method according to claim 5, characterized in that: When the first relay (S L2 ) is connected to the third end, the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter also includes: calculating a voltage difference between a first output terminal (L) and the first input terminal (L1), and a voltage difference between the second output terminal (N) and the third input terminal (N1); When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than the second threshold voltage and greater than the first threshold voltage, it is determined to be a third fault type; When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than a first threshold voltage, determining that it is a fifth fault type; When the voltage difference between the second output terminal (N) and the third input terminal (N1) is less than the second threshold voltage and greater than the first threshold voltage, it is determined to be a fourth fault type; When the voltage difference between the second output terminal (N) and the third input terminal (N1) is less than a first threshold voltage, it is determined to be a sixth fault type.

11. The fault detection method according to claim 5, characterized in that: When the first normally open relay (S L1 ) and the second normally open relay (S N1 ), the first relay (S L2 ) is connected to the third end, the second relay (S N2 ) is connected to the third end, judging the fault type of the relay control circuit according to the voltage parameter also includes: calculating a voltage difference between a first output terminal (L) and the first input terminal (L1), and a voltage difference between the second output terminal (N) and the third input terminal (N1); When the voltage difference between the first output terminal (L) and the first input terminal (L1) is less than the second threshold voltage and greater than the first threshold voltage, it is determined to be a third fault type or a fourth fault type; When the voltage difference between the second output terminal (N) and the third input terminal (N1) is greater than a second threshold voltage, it is determined to be an eighth fault type. When the voltage difference between the second output terminal (N) and the third input terminal (N1) is smaller than the second threshold voltage and larger than the first threshold voltage, it is determined as the fourth fault type and the eighth fault type.

12. The fault detection method according to claim 5, characterized in that: Also includes: When the relay control circuit is in a first fault type or a second fault type, prohibiting the relay control circuit from operating in an in-vehicle discharge mode; When the relay control circuit is in at least one of the third fault type, the fourth fault type, the fifth fault type, and the sixth fault type, prohibiting the relay control circuit from operating in the charging mode, the off-vehicle discharge mode, and the on-vehicle discharge mode; When the relay control circuit is in the seventh fault type or the eighth fault type, the relay control circuit is prohibited from operating in the charging mode and the off-vehicle discharging mode.

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