A contactor adhesion detection circuit

Abstract

The invention discloses an energy storage battery cluster contactor adhesion detection circuit, comprising a battery cluster, a Hall sensor, a main contactor, a pre-charge contactor, a current limiting resistor, a first adhesion detection control optocoupler, a first adhesion detection optocoupler, a second adhesion detection control optocoupler, a second adhesion detection optocoupler, a bidirectional energy storage inverter, a battery management system and a low voltage source. The circuit has high detection accuracy, low logic complexity and high safety.

Description

Technical Field

[0001] The invention relates to a detection circuit, in particular to a contactor adhesion detection circuit. Background Art

[0002] The current energy storage system is composed of multiple battery clusters. A single battery cluster is equipped with a main contactor and a pre-charge contactor. After the system is powered on, the battery management system detects that there is no abnormality in the battery cluster and closes the pre-charge contactor first. When the voltage across the pre-charge contactor reaches a certain difference, the main contactor is closed to protect the main contactor from large current shocks.

[0003] After pre-charging, the system closes the main contactor and can enter the normal charging and discharging working state. With the long-term operation of the system and the aging of devices, the contactor contacts may become stuck due to heat generated by long-term load operation during the charging and discharging process of the battery cluster. This requires the battery management system to detect whether the contactor contacts are stuck to ensure that the system prompts and intervenes in time in abnormal situations to avoid overcharging or over-discharging of the battery cluster due to the inability to disconnect the contactor contacts.

[0004] Existing technologies such as Figure 2 As shown, the battery management system is powered on. At this time, the battery management system performs contactor adhesion status detection. Both contactors are in the disconnected state. The battery management system prioritizes voltage detection point 1. Since voltage detection point 1 is the positive electrode of the battery cluster, it reflects the total voltage of the battery cluster, so there will always be a detection value corresponding to the battery cluster voltage.

[0005] After the battery management system detects the voltage at voltage detection point 1, it then performs voltage detection point 2. At this time, the battery management system has two control contactors that are closed and both contactors are in a disconnected state. Voltage detection point 2 should be in a no-voltage state. If the battery management system detects that the voltage at voltage detection point 2 is consistent with the voltage at voltage detection point 1, it is judged as contactor adhesion and a corresponding alarm is issued.

[0006] However, the prior art has the following disadvantages:

[0007] In the prior art solution, when the battery management system does not control the contactor to close, the voltage at voltage detection point 1 and voltage detection point 2 are compared to determine whether the contactor is stuck through software. When any of the two contactors is stuck, the voltage at voltage detection point 2 will have a voltage value close to that at voltage detection point 1, making it difficult to determine whether the pre-charge contactor is stuck or the main contactor is stuck. The reliability is low and it is difficult to effectively indicate a fault.

[0008] When the battery system has frequent charge and discharge switching, or power-on and power-off operations, if there is residual voltage on the PCS side, the voltage detection point 2 will have a certain voltage value, which may cause a large detection error and a false alarm fault.

[0009] However, this solution also requires that the battery system must be strictly coordinated with the PCS or discharge sequence, which increases the complexity of the logic and reduces safety. Summary of the invention

[0010] The purpose of the present invention is to overcome the disadvantages of the prior art and provide a contactor adhesion detection circuit, which has high detection accuracy, low logic complexity and high safety.

[0011] To achieve the above-mentioned object, the contactor adhesion detection circuit described in the present invention includes a battery cluster, a Hall sensor, a main contactor, a pre-charge contactor, a current limiting resistor, a first adhesion detection control optocoupler, a first adhesion detection optocoupler, a second adhesion detection control optocoupler, a second adhesion detection optocoupler, a bidirectional energy storage inverter, a battery management system and a low-voltage power supply;

[0012] The positive electrode of the battery cluster is connected to one end of the main contactor, pin No. 4 of the first adhesion detection control optocoupler and one end of the current limiting resistor via the Hall sensor, the other end of the current limiting resistor is connected to one end of the pre-charging contactor and pin No. 4 of the second adhesion detection control optocoupler, the other end of the main contactor, the other end of the pre-charging contactor, pin No. 2 of the first adhesion detection optocoupler, pin No. 2 of the second adhesion detection optocoupler and the positive electrode on the DC side of the bidirectional energy storage converter are connected, the negative electrode on the DC side of the bidirectional energy storage converter is connected to the negative electrode of the battery cluster, pin No. 3 of the first adhesion detection control optocoupler is connected to pin No. 1 of the first adhesion detection optocoupler via the first resistor, and pin No. 3 of the second adhesion detection control optocoupler is connected to pin No. 1 of the second adhesion detection optocoupler via the second resistor;

[0013] The battery management system is connected to the Hall sensor, pin 2 of the first adhesion detection control optocoupler, pin 2 of the second adhesion detection control optocoupler, pin 4 of the first adhesion detection optocoupler, pin 4 of the second adhesion detection optocoupler, the control end of the main contactor and the control end of the pre-charge contactor;

[0014] Pin 1 of the first adhesion detection control optocoupler is connected to the low voltage source via the third resistor; Pin 4 of the first adhesion detection optocoupler is connected to the low voltage source via the fourth resistor, Pin 1 of the second adhesion detection control optocoupler is connected to the low voltage source via the fifth resistor, and Pin 4 of the second adhesion detection optocoupler is connected to the low voltage source via the sixth resistor;

[0015] Pin 3 of the first adhesion detection optocoupler and pin 3 of the second adhesion detection optocoupler are both grounded.

[0016] During operation, after the battery management system is powered on, the main contactor and the pre-charge contactor are in a disconnected state, and the battery management system controls the first adhesion detection control optocoupler pins 3 and 4 to be turned on. When the main contactor is adhered at this time, the total voltage and current of the battery cluster are directly connected to the load side through the contacts of the main contactor, and no current flows through pins 3 and 4 of the first adhesion detection control optocoupler and pins 1 and 2 of the first adhesion detection optocoupler. Pins 3 and 4 of the first adhesion detection optocoupler are in a non-conducting state, and pin 4 of the second adhesion detection optocoupler is at a high level. The battery management system determines that the main contactor is adhered and issues a corresponding alarm;

[0017] During operation, after the battery management system is powered on, the main contactor and the pre-charge contactor are in a disconnected state, and the battery management system controls the No. 3 and No. 4 pins of the first adhesion detection control optocoupler to be turned on. When the main contactor is not adhered at this time, the total voltage and current of the battery cluster are connected to the load side through the No. 3 and No. 4 pins of the first adhesion detection control optocoupler and the No. 1 and No. 2 pins of the first adhesion detection optocoupler, and the No. 3 and No. 4 pins of the first adhesion detection optocoupler are in a conducting state, and the No. 4 pin of the first adhesion detection optocoupler is at a low level, and the battery management system determines that the contacts of the main contactor are normally in a non-adhesion state;

[0018] During operation, after the battery management system is powered on, the main contactor and the pre-charging contactor are in a disconnected state, and the battery management system controls the second adhesion detection control optocoupler to conduct pins 3 and 4. When the pre-charging contactor is adhered at this time, the total voltage and current of the battery cluster are directly connected to the load side through the contacts of the pre-charging contactor, and no current flows through pins 3 and 4 of the second adhesion detection control optocoupler and pins 1 and 2 of the second adhesion detection optocoupler. Pins 3 and 4 of the second adhesion detection optocoupler are in a non-conducting state, and pin 4 of the second adhesion detection optocoupler is at a high level. The battery management system determines that the pre-charging contactor is adhered and sends a corresponding alarm signal;

[0019] During operation, after the battery management system is powered on, the main contactor and the pre-charge contactor are in a disconnected state, and the battery management system controls the No. 3 and No. 4 pins of the second adhesion detection control optocoupler to be turned on. When the main contactor is not adhered at this time, the total voltage and current of the battery cluster are connected to the load side through the No. 3 and No. 4 pins of the second adhesion detection control optocoupler and the No. 1 and No. 2 pins of the second adhesion detection optocoupler, and the No. 3 and No. 4 pins of the second adhesion detection optocoupler are in a conducting state, and the No. 4 pin of the second adhesion detection optocoupler is at a low level, and the battery management system determines that the contacts of the pre-charge contactor are normally in a non-adhesion state;

[0020] During operation, when the battery management system detects that the main contactor and the pre-charge contactor are both in a non-sticky state, the main contactor and the pre-charge contactor are closed, and the battery cluster performs charging and discharging operations; otherwise, an alarm prompts and the system prohibits charging and discharging.

[0021] The present invention has the following beneficial effects:

[0022] During specific operation, the contactor adhesion detection circuit described in the present invention controls the switch states of the main contactor and the pre-charge contactor, and determines the adhesion states of the two contactors according to the voltage levels of pin 4 in the first adhesion detection optocoupler and pin 4 in the second adhesion detection optocoupler. At the same time, it distinguishes whether the current adhesion is adhesion of the pre-charge contactor or adhesion of the main contactor, so as to effectively locate the fault point. The circuit has the characteristics of low logical complexity and high safety, and is independent of the load side and the overall timing of the system. The optocoupler detection current can be as low as 1 mA, and does not affect the function and performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 It is a structural schematic diagram of the prior art. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0026] The accompanying drawings show schematic diagrams of structures according to embodiments disclosed in the present invention. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0027] refer to Figure 1The contactor adhesion detection circuit of the present invention includes a battery cluster D, a Hall sensor H1, a main contactor K1, a pre-charge contactor K2, a current limiting resistor R1, a first adhesion detection control optical coupler U1, a first adhesion detection optical coupler U2, a second adhesion detection control optical coupler U3, a second adhesion detection optical coupler U4, a bidirectional energy storage converter PCS, a battery management system BMU and a low voltage source VCC;

[0028] The positive electrode of the battery cluster D is connected to one end of the main contactor K1, pin No. 4 of the first adhesion detection control optocoupler U1 and one end of the current limiting resistor R1 through the Hall sensor H1, the other end of the current limiting resistor R1 is connected to one end of the pre-charging contactor K2 and pin No. 4 of the second adhesion detection control optocoupler U3, the other end of the main contactor K1, the other end of the pre-charging contactor K2, pin No. 2 of the first adhesion detection optocoupler U2, pin No. 2 of the second adhesion detection optocoupler U4 and the positive electrode of the DC side in the bidirectional energy storage converter PCS are connected, the negative electrode of the DC side in the bidirectional energy storage converter PCS is connected to the negative electrode of the battery cluster D, pin No. 3 of the first adhesion detection control optocoupler U1 is connected to pin No. 1 of the first adhesion detection optocoupler U2 through the first resistor, and pin No. 3 of the second adhesion detection control optocoupler U3 is connected to pin No. 1 of the second adhesion detection optocoupler U4 through the second resistor;

[0029] The battery management system BMU is connected to the Hall sensor H1, the No. 2 pin of the first adhesion detection control optocoupler U1, the No. 2 pin of the second adhesion detection control optocoupler U3, the No. 4 pin of the first adhesion detection optocoupler U2, the No. 4 pin of the second adhesion detection optocoupler U4, the control end of the main contactor K1 and the control end of the pre-charge contactor K2;

[0030] Pin 1 of the first adhesion detection control optocoupler U1 is connected to the low voltage source VCC via the third resistor; pin 4 of the first adhesion detection optocoupler U2 is connected to the low voltage source VCC via the fourth resistor, pin 1 of the second adhesion detection control optocoupler U3 is connected to the low voltage source VCC via the fifth resistor, and pin 4 of the second adhesion detection optocoupler U4 is connected to the low voltage source VCC via the sixth resistor.

[0031] Pin 3 of the first adhesion detection optocoupler U2 and pin 3 of the second adhesion detection optocoupler U4 are both grounded.

[0032] The working process of the present invention is:

[0033] 1) Main contactor K1 adhesion detection

[0034] After the battery management system BMU is powered on, the main contactor K1 and the pre-charge contactor K2 are in the disconnected state. The battery management system BMU controls the first adhesion detection control optocoupler U1 to conduct pins 3 and 4. When the main contactor K1 is adhered at this time, the total voltage and current of the battery cluster D are directly connected to the load side through the contacts of the main contactor K1. No current flows through pins 3 and 4 of the first adhesion detection control optocoupler U1 and pins 1 and 2 of the first adhesion detection optocoupler U2. Pins 3 and 4 of the first adhesion detection optocoupler U2 are in the non-conducting state. Pin 4 of the second adhesion detection optocoupler U4 is at a high level. The battery management system BMU determines that the main contactor K1 is adhered and issues a corresponding alarm.

[0035] After the battery management system BMU is powered on, the main contactor K1 and the pre-charge contactor K2 are in the disconnected state, and the battery management system BMU controls the first adhesion detection control optocoupler U1 to control pins 3 and 4 to be turned on. When the main contactor K1 is not adhered at this time, the total voltage and current of the battery cluster D are connected to the load side through pins 3 and 4 of the first adhesion detection control optocoupler U1 and pins 1 and 2 of the first adhesion detection optocoupler U2. Pins 3 and 4 of the first adhesion detection optocoupler U2 are in the on state, and pin 4 of the first adhesion detection optocoupler U2 is at a low level. The battery management system BMU determines that the contacts of the main contactor K1 are normally in a non-adhesion state;

[0036] 2) Pre-charge contactor K2 adhesion detection

[0037] After the battery management system BMU is powered on, the main contactor K1 and the pre-charging contactor K2 are in the disconnected state, and the battery management system BMU controls the second adhesion detection control optocoupler U3 to conduct pins 3 and 4. When the pre-charging contactor K2 is adhered at this time, the total voltage and current of the battery cluster D are directly connected to the load side through the contact of the pre-charging contactor K2, and no current flows through pins 3 and 4 of the second adhesion detection control optocoupler U3 and pins 1 and 2 of the second adhesion detection optocoupler U4. Pins 3 and 4 of the second adhesion detection optocoupler U4 are in the non-conducting state, and pin 4 of the second adhesion detection optocoupler U4 is at a high level. The battery management system BMU determines that the pre-charging contactor K2 is adhered, and sends a corresponding alarm signal;

[0038] After the battery management system BMU is powered on, the main contactor K1 and the pre-charging contactor K2 are in the disconnected state, and the battery management system BMU controls the No. 3 and No. 4 pins of the second adhesion detection control optocoupler U3 to be turned on. When the main contactor K1 is not adhered at this time, the total voltage and current of the battery cluster D are connected to the load side through the No. 3 and No. 4 pins of the second adhesion detection control optocoupler U3 and the No. 1 and No. 2 pins of the second adhesion detection optocoupler U4, and the No. 3 and No. 4 pins of the second adhesion detection optocoupler U4 are in the on state, and the No. 4 pin of the second adhesion detection optocoupler U4 is at a low level, and the battery management system BMU determines that the contact of the pre-charging contactor K2 is normally in a non-adhesion state;

[0039] 3) When the battery management system BMU detects that both the main contactor K1 and the pre-charge contactor K2 are in a non-adhesive state, the main contactor K1 and the pre-charge contactor K2 are closed, and the battery cluster D performs charging and discharging operations; otherwise, an alarm is issued to prompt the PCS and the system to prohibit charging and discharging.

[0040] It should be noted that the present invention controls the switching states of the main contactor K1 and the pre-charging contactor K2, and can determine the adhesion state of the two contactors according to the voltage at pin 4 in the first adhesion detection optocoupler U2 and pin 4 in the second adhesion detection optocoupler U4, and at the same time distinguish whether the current adhesion is the adhesion of the pre-charging contactor or the main contactor. The operation is convenient, simple, and extremely practical.

Claims

1. A contactor adhesion detection circuit, characterized in that: It includes a battery cluster (D), a Hall sensor (H1), a main contactor (K1), a pre-charge contactor (K2), a current limiting resistor (R1), a first adhesion detection control optocoupler (U1), a first adhesion detection optocoupler (U2), a second adhesion detection control optocoupler (U3), a second adhesion detection optocoupler (U4), a bidirectional energy storage converter (PCS), a battery management system (BMU) and a low voltage source (VCC); The positive electrode of the battery cluster (D) is connected to one end of the main contactor (K1), the No. 4 pin of the first adhesion detection control optical coupler (U1) and one end of the current limiting resistor (R1) through a Hall sensor (H1), the other end of the current limiting resistor (R1) is connected to one end of the pre-charge contactor (K2) and the No. 4 pin of the second adhesion detection control optical coupler (U3), the other end of the main contactor (K1), the other end of the pre-charge contactor (K2), the No. 2 pin of the first adhesion detection optical coupler (U2), the No. 3 pin of the second adhesion detection optical coupler (U3) and the No. 4 pin of the second adhesion detection optical coupler (U3). A No. 2 pin of a bonding detection optocoupler (U4) and a positive electrode of a DC side in a bidirectional energy storage converter (PCS) are connected, a negative electrode of a DC side in the bidirectional energy storage converter (PCS) is connected to a negative electrode of a battery cluster (D), a No. 3 pin of a first bonding detection control optocoupler (U1) is connected to a No. 1 pin of a first bonding detection optocoupler (U2) via a first resistor, and a No. 3 pin of a second bonding detection control optocoupler (U3) is connected to a No. 1 pin of a second bonding detection optocoupler (U4) via a second resistor; The battery management system (BMU) is connected to the Hall sensor (H1), the No. 2 pin of the first adhesion detection control optical coupler (U1), the No. 2 pin of the second adhesion detection control optical coupler (U3), the No. 4 pin of the first adhesion detection optical coupler (U2), the No. 4 pin of the second adhesion detection optical coupler (U4), the control end of the main contactor (K1) and the control end of the pre-charge contactor (K2); Pin No. 1 of the first adhesion detection control optical coupler (U1) is connected to a low voltage source (VCC) via a third resistor; Pin No. 4 of the first adhesion detection optical coupler (U2) is connected to the low voltage source (VCC) via a fourth resistor, Pin No. 1 of the second adhesion detection control optical coupler (U3) is connected to the low voltage source (VCC) via a fifth resistor, and Pin No. 4 of the second adhesion detection optical coupler (U4) is connected to the low voltage source (VCC) via a sixth resistor; Pin 3 of the first adhesion detection optocoupler (U2) and pin 3 of the second adhesion detection optocoupler (U4) are both grounded; During operation, after the battery management system (BMU) is powered on, the main contactor (K1) and the pre-charge contactor (K2) are in a disconnected state, and the battery management system (BMU) controls the No. 3 and No. 4 pins of the first adhesion detection control optical coupler (U1) to be turned on. When the main contactor (K1) is adhered at this time, the total voltage and current of the battery cluster (D) are directly connected to the load side through the contacts of the main contactor (K1), and no current flows through the No. 3 and No. 4 pins of the first adhesion detection control optical coupler (U1) and the No. 1 and No. 2 pins of the first adhesion detection optical coupler (U2). The No. 3 and No. 4 pins of the first adhesion detection optical coupler (U2) are in a non-conducting state, and the No. 4 pin of the second adhesion detection optical coupler (U4) is at a high level. The battery management system (BMU) determines that the main contactor (K1) is adhered, and issues a corresponding alarm; During operation, after the battery management system (BMU) is powered on, the main contactor (K1) and the pre-charge contactor (K2) are in a disconnected state, and the battery management system (BMU) controls the No. 3 and No. 4 pins of the first adhesion detection control optocoupler (U1) to be turned on. When the main contactor (K1) is not adhered at this time, the total voltage and current of the battery cluster (D) are connected to the load side through the No. 3 and No. 4 pins of the first adhesion detection control optocoupler (U1) and the No. 1 and No. 2 pins of the first adhesion detection optocoupler (U2). The No. 3 and No. 4 pins of the first adhesion detection optocoupler (U2) are in a conducting state, and the No. 4 pin of the first adhesion detection optocoupler (U2) is at a low level. The battery management system (BMU) determines that the contacts of the main contactor (K1) are normally in a non-adhesion state.

2. The contactor adhesion detection circuit according to claim 1, characterized in that: During operation, after the battery management system (BMU) is powered on, the main contactor (K1) and the pre-charging contactor (K2) are in a disconnected state, and the battery management system (BMU) controls the No. 3 and No. 4 pins of the second adhesion detection control optical coupler (U3) to be turned on. When the pre-charging contactor (K2) is adhered at this time, the total voltage and current of the battery cluster (D) are directly connected to the load side through the contact of the pre-charging contactor (K2), and no current flows through the No. 3 and No. 4 pins of the second adhesion detection control optical coupler (U3) and the No. 1 and No. 2 pins of the second adhesion detection optical coupler (U4). The No. 3 and No. 4 pins of the second adhesion detection optical coupler (U4) are in a non-conducting state, and the No. 4 pin of the second adhesion detection optical coupler (U4) is at a high level. The battery management system (BMU) determines that the pre-charging contactor (K2) is adhered, and sends a corresponding alarm signal.

3. The contactor adhesion detection circuit according to claim 1, characterized in that: During operation, after the battery management system (BMU) is powered on, the main contactor (K1) and the pre-charging contactor (K2) are in a disconnected state, and the battery management system (BMU) controls the No. 3 and No. 4 pins of the second adhesion detection control optocoupler (U3) to be turned on. When the main contactor (K1) is not adhered at this time, the total voltage and current of the battery cluster (D) are connected to the load side through the No. 3 and No. 4 pins of the second adhesion detection control optocoupler (U3) and the No. 1 and No. 2 pins of the second adhesion detection optocoupler (U4). The No. 3 and No. 4 pins of the second adhesion detection optocoupler (U4) are in a conducting state, and the No. 4 pin of the second adhesion detection optocoupler (U4) is at a low level. The battery management system (BMU) determines that the contacts of the pre-charging contactor (K2) are normally in a non-adhesive state.

4. The contactor adhesion detection circuit according to claim 1, characterized in that: During operation, when the battery management system (BMU) detects that the main contactor (K1) and the pre-charge contactor (K2) are both in a non-adhesive state, the main contactor (K1) and the pre-charge contactor (K2) are closed, and the battery cluster (D) performs charging and discharging operations; Otherwise, an alarm will be given and the system will prohibit charging and discharging.

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