A battery detection circuit and control method for bidirectional converter

Abstract

The present invention provides a battery detection circuit applied to a bidirectional converter, comprising a discharge circuit, a battery detection and logic control circuit, a relay, a port capacitor and an internal filter capacitor, wherein the discharge circuit comprises a discharge switch tube, a first discharge resistor and a second discharge resistor, and the battery detection and logic control circuit comprises an analysis and processing unit; the analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube, in1 of the analysis and processing unit and one end of the second discharge resistor, a contact at one end of the relay and one end of the internal filter capacitor have a first node, the first node is externally connected to a first port, in2 of the analysis and processing unit and one end of the first discharge resistor, the other end of the second discharge resistor, a contact at the other end of the relay and one end of the port capacitor have a second node, the second node is externally connected to a second port, and the other end of the first discharge resistor is connected to the drain of the discharge switch tube.

Description

Technical Field

[0001] The invention relates to a detection circuit, in particular to a battery detection circuit applied to a bidirectional converter and a control method thereof. Background Art

[0002] With the rapid development of smart grids and energy interconnection, products that can convert and transmit electric energy bidirectionally have become a hot market in this field. For high-voltage bidirectional converters, there is a technical difficulty: safety regulations require that the port voltage be reduced to below 60V within 1 second after the power is turned off to ensure the safety of power supply operators and maintenance personnel. At present, the mainstream method in the industry to solve this problem is to add a port discharge circuit to discharge the output port immediately after the power is turned off. The advantage of this method is that it is simple and easy to implement, and can solve the port discharge in most cases. The disadvantage is that when the converter port is connected in parallel with a battery, the discharge circuit will discharge the battery. Since the battery has a large amount of energy, the discharge resistor will be damaged by overpower. Summary of the invention

[0003] The technical problem to be solved by the present invention is that reliable discharge cannot be performed under various circumstances.

[0004] In order to solve the above technical problems, the present invention provides a battery detection circuit applied to a bidirectional converter, including a discharge circuit, a battery detection and logic control circuit, a relay, a port capacitor and an internal filter capacitor, wherein:

[0005] The discharge circuit includes a discharge switch tube, a first discharge resistor and a second discharge resistor, and the battery detection and logic control circuit includes an analysis and processing unit;

[0006] The analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube, in1 of the analysis and processing unit has a first node with a contact at one end of the relay and one end of the internal filter capacitor, the first node is externally connected to a first port, one end of the second discharge resistor is connected to the first node, in2 of the analysis and processing unit has a second node with the other end of the second discharge resistor and a contact at the other end of the relay, the second node is externally connected to a second port, one end of the first discharge resistor is connected to the second node and the other end is connected to the drain of the discharge switch tube, one end of the port capacitor is connected to the second node, and the source of the discharge switch tube, the other end of the port capacitor and the other end of the internal filter capacitor are grounded together.

[0007] Furthermore, it also includes a third resistor and a fourth resistor, one end of the third resistor is connected to the second node, one end of the fourth resistor is connected to the first node, and the other ends of the third resistor and the fourth resistor are commonly grounded.

[0008] Furthermore, it also includes a battery, one end of the battery is connected to the second node, and the other end of the battery is connected to the source of the discharge switch tube.

[0009] Furthermore, it also includes a high-frequency conversion circuit, one end of which is connected to the first node, and the other end of which is grounded.

[0010] Furthermore, a control method for a battery detection circuit applied to a bidirectional converter is provided, using any of the battery detection circuits described above, the control method comprising the following steps:

[0011] The converter is shut down, the relay is disconnected and delayed for a time ΔT after disconnection, and the voltage value ΔV1 of the sample V1 is controlled;

[0012] If V1>ΔV1, discharge for T1 time and detect the falling slope of V1;

[0013] If the V1 falling slope is greater than 500V / S, the port is judged to be equipped with a battery, the discharge is terminated, and an abnormal discharge alarm is issued.

[0014] Furthermore, if V1<ΔV1, it is determined that the port has no battery and the discharge continues for T2 time; if V1≥ΔV2, it is determined that the port has a battery, the discharge is exited and a discharge abnormality alarm is issued.

[0015] Furthermore, if V1≤ΔV2, it is determined that the port does not have a battery.

[0016] Furthermore, if the falling slope of V1 is less than 500V / S, it is considered that the port has no battery and continues to discharge for T2 time; if V1≥ΔV2, it is determined that the port has a battery, the discharge is exited and a discharge abnormality alarm is issued.

[0017] Furthermore, if V1≤ΔV2, it is determined that the port does not have a battery.

[0018] The beneficial effect of the present invention is that the present invention provides a battery detection circuit for a bidirectional converter, including a discharge circuit, a battery detection and logic control circuit, a relay, a port capacitor and an internal filter capacitor, wherein the discharge circuit includes a discharge switch tube, a first discharge resistor and a second discharge resistor, and the battery detection and logic control circuit includes an analysis and processing unit; the analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube, in1 of the analysis and processing unit and a contact at one end of the relay and an end of the internal filter capacitor have a first node, the first node is externally connected to the first port, one end of the second discharge resistor is connected to the first node, in2 of the analysis and processing unit and the other end of the second discharge resistor and a contact at the other end of the relay have a second node, the second node is externally connected to the second port, one end of the first discharge resistor is connected to the second node and the other end is connected to the drain of the discharge switch tube, one end of the port capacitor is connected to the second node, and the source of the discharge switch tube, the other end of the port capacitor and the other end of the internal filter capacitor are grounded together. Through the software logic control algorithm, whether the port is connected in parallel with the battery is detected, and then the discharge time and discharge termination voltage of the discharge circuit are controlled to ensure that the discharge circuit can be reliably discharged under various circumstances. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The specific structure of the present invention is described in detail below with reference to the accompanying drawings

[0020] Figure 1 is a circuit diagram of Embodiment 1 of the present invention;

[0021] Figure 2 is a circuit diagram of Embodiment 1 of the present invention;

[0022] Figure 3 This is a circuit diagram of Embodiment 2 of the present invention;

[0023] Figure 4 This is a circuit diagram of Embodiment 3 of the present invention;

[0024] Figure 5 It is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0025] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0026] Example 1

[0027] See also Figure 1 as well as Figure 2The present invention provides a battery detection circuit for a bidirectional converter, comprising a discharge circuit Part_1 of a port, a battery detection and logic control circuit Part_2, a relay RL1, a port capacitor C1 and an internal filter capacitor C2, wherein the discharge circuit Part_1 comprises a discharge switch tube Q1, a first discharge resistor R1 and a second discharge resistor R2, and the battery detection and logic control circuit Part_2 comprises an analysis processing unit; the analysis processing unit outputs a driver1 signal to the gate of the discharge switch tube Q1, and the in1 of the analysis processing unit is connected to one end of the relay RL1 The contact of the analysis and processing unit and one end of the internal filter capacitor C2 have a first node S1, the first node S1 is externally connected to the first port, one end of the second discharge resistor is connected to the first node S1, in2 of the analysis and processing unit and the other end of the second discharge resistor R2 and the other end of the relay RL1 have a second node S2, the second node S2 is externally connected to the second port, one end of the first discharge resistor R1 is connected to the second node S2 and the other end is connected to the drain of the discharge switch tube Q1, one end of the port capacitor is connected to the second node S2, the source of the discharge switch tube Q1, the other end of the port capacitor C1 and the other end of the internal filter capacitor C2 are grounded together.

[0028] When the discharge switch tube Q1 is turned on, the port capacitor C1 and the internal filter capacitor C2 are discharged. The judgment of whether the port is connected to the battery and the switch control of the discharge switch tube Q1 are realized through the second port port voltage V1 and the internal voltage V2 of the first port in combination with the control logic algorithm. Among them, the relay RL1 is a relay between the port and the internal converter. When the converter works normally, the relay RL1 is closed. When the converter is shut down or fails, the relay RL1 is disconnected.

[0029] From the above description, it can be seen that the beneficial effect of the present invention is that: through the software logic control algorithm, whether the port is connected in parallel with the battery is detected, and then the discharge time and discharge termination voltage of the discharge circuit are controlled to ensure that the discharge circuit can perform reliable discharge under various conditions.

[0030] Furthermore, it also includes a third resistor R3 and a fourth resistor R4, one end of the third resistor R3 is connected to the second node S2, one end of the fourth resistor R4 is connected to the first node S1, and the other ends of the third resistor R3 and the fourth resistor R4 are grounded together to protect the circuit and avoid burning.

[0031] Furthermore, it also includes a battery Part_3 with ports connected in parallel, one end of the battery Part_3 is connected to the second node S2, and the other end is connected to the source of the discharge switch tube Q1. The battery Part_3 can also be other parallel DC power supply modules.

[0032] Furthermore, it also includes transforming the high-frequency conversion circuit Part_4 inside it. The high-frequency conversion circuit is an AC-DC bidirectional converter. One end of the AC-DC bidirectional converter is connected to the first node S1 and the other end is grounded to achieve control of the bidirectional flow of energy.

[0033] Example 2

[0034] See also Figure 3 The structure of the above embodiment is only one implementation mode of the present invention and is not limited to the above Figure 2 The structure shown can also be implemented as another embodiment as shown in the following embodiment.

[0035] Discharge circuit Part_1, battery detection and logic control circuit Part_2, relay RL1, port capacitor C1 and internal filter capacitor C2, wherein the discharge circuit Part_1 includes a discharge switch tube Q1, a first discharge resistor R1 and a second discharge resistor R2, and the battery detection and logic control circuit Part_2 includes an analysis and processing unit; the analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube Q1, the contact of in1 of the analysis and processing unit with one end of the relay RL1 and one end of the internal filter capacitor C2 has a third node S3, the third node S3 is externally connected to the first port, the contact of in2 of the analysis and processing unit with the other end of the relay RL1 has a fourth node S4, the fourth node S4 is externally connected to the second port, one end of the first discharge resistor R1, one end of the second discharge resistor and the drain of the discharge switch tube Q1 have a fifth node S5, the other end of the second discharge resistor R2 is connected to the third node S3, the other end of the first discharge resistor R1 and one end of the port capacitor C1 are connected to the fourth node S4, the source of the discharge switch tube Q1, the other end of the port capacitor C1 and the other end of the internal filter capacitor C2 are grounded together. Figure 1 Compared with the structure shown, except for the above differences, the rest are the same, so they will not be described here.

[0036] Example 3

[0037] See also Figure 4 The structure of the above embodiment is only one implementation of the present invention and is not limited to the structure shown in the above embodiment 1 or embodiment 2. The structure of the following embodiment can also be used as another implementation.

[0038] Discharge circuit Part_1, battery detection and logic control circuit Part_2, relay RL1, port capacitor C1 and internal filter capacitor C2, wherein the discharge circuit Part_1 includes a discharge switch tube Q1, a first discharge resistor R1 and a second discharge resistor R2, and the battery detection and logic control circuit Part_2 includes an analysis and processing unit; the analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube Q1, the analysis and processing unit in1 and the contact at one end of the relay RL1 and one end of the internal filter capacitor C2 have a sixth node S6, and the sixth node S6 is externally connected to the first port, the analysis and processing unit in2 and the contact at the other end of the relay RL1 and one end of the second discharge resistor R2 have a seventh node S7, and the seventh node S7 is externally connected to the second port, one end of the first discharge resistor R1 and the other end of the second discharge resistor R2 are connected to the sixth node S6, the other end of the first discharge resistor R1 is connected to the drain of the discharge switch tube Q1, and the source of the discharge switch tube Q1, the other end of the port capacitor C1 and the other end of the internal filter capacitor C2 are grounded together. Figure 1 Compared with the structure shown, except for the above differences, the rest are the same, so they will not be described here.

[0039] Example 4

[0040] See also Figure 5 , and also provides a control method for a battery detection circuit applied to a bidirectional converter, using a battery detection circuit such as any of the above, and judging the characteristics of the port voltage by delaying or short-time detective discharge to detect the voltage drop slope, and then determining whether it is connected to a battery, and sampling different discharge methods for connecting a battery and not connecting a battery. The specific control method includes the following steps:

[0041] After the converter is shut down, the relay RL1 will be disconnected. After the relay RL1 is disconnected, a delay of ΔT is made to control the voltage value ΔV1 of the sampled V1 and make a judgment. If V1>ΔV1, a short-term discharge of T1 time is performed to detect the falling slope of V1; if the falling slope of V1>500V / S, it is judged that the port has a battery, and then the discharge is exited, and a discharge abnormality alarm is issued; if the falling slope of V1<500V / S, it is considered that the port does not have a battery and continues to discharge for T2 time; if V1≥ΔV2, it is judged that the port has a battery, and then the discharge is exited, and a discharge abnormality alarm is issued. If V1≤ΔV2, it is judged that the port does not have a battery.

[0042] After the converter is shut down, the relay RL1 will be disconnected. After the relay RL1 is disconnected, a delay of ΔT is made to control the voltage value ΔV1 of the sampled V1 and make a judgment. If V1<ΔV1, it is judged that the port does not have a battery and continues to discharge for T2 time. If V1≥ΔV2, it is judged that the port has a battery, and then the discharge is exited and a discharge abnormality alarm is issued. If V1≤ΔV2, it is judged that the port does not have a battery.

[0043] In summary, the present invention provides a battery detection circuit and a control method thereof for a bidirectional converter, which detects whether a port is connected in parallel with a battery through a software logic control algorithm, and then controls the discharge time and discharge termination voltage of the discharge circuit to ensure that the discharge circuit can perform reliable discharge under various conditions.

[0044] Here, the first, second... only represent the distinction in their names, and do not represent any difference in their importance and position.

[0045] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control method for a battery detection circuit applied to a bidirectional converter, characterized in that: The battery detection circuit used includes a discharge circuit, a battery detection and logic control circuit, a relay, a port capacitor and an internal filter capacitor, among which: The discharge circuit includes a discharge switch tube, a first discharge resistor and a second discharge resistor, and the battery detection and logic control circuit includes an analysis and processing unit; The analysis and processing unit outputs a driver1 signal to the gate of the discharge switch tube, in1 of the analysis and processing unit and a contact at one end of the relay and an end of the internal filter capacitor have a first node, the first node is externally connected to a first port, one end of the second discharge resistor is connected to the first node, in2 of the analysis and processing unit and a contact at the other end of the second discharge resistor and the other end of the relay have a second node, the second node is externally connected to a second port, one end of the first discharge resistor is connected to the second node and the other end is connected to the drain of the discharge switch tube, one end of the port capacitor is connected to the second node, and the source of the discharge switch tube, the other end of the port capacitor and the other end of the internal filter capacitor are grounded together; The control method comprises the following steps: The converter is shut down, the relay is disconnected and delayed for a time ΔT after disconnection, and the voltage value ΔV1 of the sample V1 is controlled; If V1>ΔV1, then discharge for T1 time and detect the falling slope of V1; If the V1 falling slope is greater than 500V / S, the port is judged to be equipped with a battery, the discharge is terminated, and an abnormal discharge alarm is issued; If the V1 falling slope is less than 500V / S, it is considered that the port has no battery and continues to discharge for T2 time; if V1≥ΔV2, it is considered that the port has a battery, exits the discharge and issues a discharge abnormality alarm; If V1≤ΔV2, it is determined that the port does not have a battery; If V1<ΔV1, it is determined that the port does not have a battery and continues to discharge for T2 time; if V1≥ΔV2, it is determined that the port has a battery, exits the discharge and issues a discharge abnormality alarm; If V1≤ΔV2, it is determined that the port does not have a battery.

2. The control method according to claim 1, characterized in that: It also includes a third resistor and a fourth resistor, wherein one end of the third resistor is connected to the second node, one end of the fourth resistor is connected to the first node, and the other ends of the third resistor and the fourth resistor are grounded together.

3. The control method according to claim 2, characterized in that: It also includes a battery, one end of which is connected to the second node, and the other end of which is connected to the source of the discharge switch tube.

4. The control method according to claim 3, characterized in that: The high-frequency conversion circuit also includes one end connected to the first node and the other end grounded.

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