Portable energy storage control system and control method

Abstract

The invention relates to the technical field of mobile power supplies, and particularly discloses a portable energy storage control system and a control method.The system comprises a low-voltage positive direct-current bus, a low-voltage negative direct-current bus and a soft start circuit, and the soft start circuit comprises a low-voltage direct-current bus capacitor C1, a pre-charging resistor R1, a pre-charging MOS tube Q4, a grounding MOS tube Q3 and a bleeder resistor R2; one end of the low-voltage direct-current bus capacitor C1 is connected with a low-voltage positive direct-current bus, and the other end of the low-voltage direct-current bus capacitor C1 is connected with one end of the pre-charging resistor R1; the other end of the pre-charging resistor R1 is connected with one end of a pre-charging MOS tube Q4, and the other end of the pre-charging MOS tube Q4 is connected with a low-voltage negative direct-current bus; one end of the bleeder resistor R2 is connected with a low-voltage positive direct current bus, and the other end of the bleeder resistor R2 is connected with one end of the R1; and one end of the grounding MOS tube Q3 is connected with the other end of the R2, and the other end of the grounding MOS tube Q3 is connected with the low-voltage negative direct-current bus. According to the technical scheme, the cost can be effectively reduced, the size is reduced, and the control process is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile power sources, and in particular to a portable energy storage control system and a control method. Background Art

[0002] Portable power banks are widely used in a variety of scenarios due to their portability and versatility, including but not limited to camping, hiking, emergency backup power, mobile work scenarios, photography and videography, and medical emergency. Portable power bank systems mainly include battery management systems (BMS), battery packs, bidirectional power converters, photovoltaic charging circuits, low-voltage DC outputs and other components.

[0003] When a portable power bank needs to be charged or discharged, the low-voltage DC bus capacitor needs to be pre-charged first, that is, soft-start, so that its voltage is close to the battery pack voltage before the BMS can close the discharge MOS. If there is no soft start, the discharge MOS of the BMS is directly closed. At the moment of closing, the battery pack will charge the low-voltage bus capacitor, and its impact current may cause the fuse to blow and the discharge MOS to be damaged.

[0004] The soft start circuit is usually realized by connecting MOS and resistor in series between the positive electrode of the battery pack and the positive electrode of the low-voltage DC bus. The MOS drive voltage is the voltage difference between the gate and the source. Since the MOS source is not connected to the system zero voltage reference point, it is usually implemented by isolation and floating ground drive. However, such isolation drive is expensive and complex to control. Alternatively, it can be implemented by using switches with isolation such as relays and contactors. However, using relays or contactors will increase the cost and the product size will also increase. Summary of the invention

[0005] One of the purposes of the present invention is to provide a portable energy storage control system that can effectively reduce costs, reduce volume, and simplify the control process.

[0006] In order to solve the above technical problems, this application provides the following technical solutions:

[0007] A portable energy storage control system includes a low-voltage positive DC bus, a low-voltage negative DC bus and a soft start circuit, wherein the soft start circuit includes a low-voltage DC bus capacitor C1, a pre-charge resistor R1, a pre-charge MOS tube Q4, a grounding MOS tube Q3, and a discharge resistor R2;

[0008] One end of the low-voltage DC bus capacitor C1 is connected to the low-voltage positive DC bus, and the other end of the low-voltage DC bus capacitor C1 is connected to one end of the pre-charging resistor R1;

[0009] The other end of the pre-charging resistor R1 is connected to one end of the pre-charging MOS tube Q4, and the other end of the pre-charging MOS tube Q4 is connected to the low-voltage negative DC bus;

[0010] One end of the discharge resistor R2 is connected to the low voltage positive DC bus, and the other end of the discharge resistor R2 is connected to one end of R1;

[0011] One end of the grounded MOS tube Q3 is connected to the other end of R2, and the other end of the grounded MOS tube Q3 is connected to the low-voltage negative DC bus.

[0012] Furthermore, it also includes an energy storage battery pack, a battery management system, a bidirectional power converter and a step-down DCDC converter;

[0013] The positive electrode and negative electrode of the energy storage battery pack are connected to the input positive electrode and input negative electrode of the battery management system respectively;

[0014] The output positive electrode and the output negative electrode of the battery management system are also connected to the low-voltage positive DC bus and the low-voltage negative DC bus respectively;

[0015] The input positive pole and the input negative pole of the bidirectional power converter are respectively connected to the low voltage positive DC bus and the low voltage negative DC bus, and the bidirectional power converter is also connected to the AC input terminal and the AC output terminal;

[0016] The other end of the grounded MOS tube Q3 is also connected to the input negative electrode of the step-down DCDC converter; the input positive electrode of the step-down DCDC converter is connected to the low-voltage positive DC bus; the step-down DCDC converter is also connected to the DC output terminal.

[0017] Furthermore, it also includes a communication bus, and the battery management system, the bidirectional power converter and the step-down DCDC converter are connected through the communication bus.

[0018] Further, it also includes a buck-boost DCDC converter;

[0019] The input positive electrode and the input negative electrode of the buck-boost DCDC converter are connected to the photovoltaic positive electrode output terminal and the photovoltaic negative electrode output terminal respectively;

[0020] The output positive electrode and the output negative electrode of the buck-boost DCDC converter are respectively connected to the input positive electrode and the input negative electrode of the buck DCDC converter;

[0021] The buck-boost DCDC converter is also connected to the communication bus.

[0022] Furthermore, the withstand voltage values ​​of the pre-charging MOS tube Q4 and the grounding MOS tube Q3 are greater than the maximum input voltage protection value of the battery management system.

[0023] Furthermore, the battery management system includes a current detection resistor Rsense connected to the output negative electrode and the low-voltage negative DC bus.

[0024] The second object of the present invention is to provide a portable energy storage control method, using the above system, including the following contents:

[0025] When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises;

[0026] After a delay of t1, the grounded MOS tube Q3 is closed;

[0027] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0028] The third object of the present invention is to provide a portable energy storage control method, using the above system, including the following contents:

[0029] When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises;

[0030] The current I of the pre-charge resistor R1 is collected through the current detection resistor Rsense R1 ;

[0031] When I R1 When the current is less than the set current threshold, the grounded MOS tube Q3 is closed;

[0032] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0033] A fourth object of the present invention is to provide a portable energy storage control method, using the above system, including the following contents:

[0034] When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises;

[0035] When the voltage V on the resistor R1 is detected R1 When it is less than the set voltage threshold, the grounding MOS tube Q3 is closed;

[0036] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0037] In this solution, when the pre-charge MOS tube Q4 is closed, due to the current limiting effect of the pre-charge resistor R1, the voltage of the low-voltage DC bus capacitor C1 will slowly rise, and there will be no large impact current; when the voltage of the low-voltage DC bus capacitor C1 is basically the same as the battery voltage V BAT When the voltage V C1 =V BAT , soft start is completed.

[0038] In summary, in this solution, the MOS tube Q3 and the MOS tube Q4 do not need to be isolated and floated, so the volume can be kept small, the cost is low and the control is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a logic block diagram of the first embodiment of the portable energy storage control system;

[0040] Figure 2 This is a logic block diagram of the fourth embodiment of the portable energy storage control system. DETAILED DESCRIPTION

[0041] The following is further described in detail through specific implementation methods:

[0042] Embodiment 1

[0043] like Figure 1 As shown, the portable energy storage control system of this embodiment includes an energy storage battery pack, a battery management system (BMS), a soft start circuit, a bidirectional power converter, a step-down DCDC converter, a low-voltage positive and negative DC bus and a communication bus;

[0044] The positive electrode and negative electrode of the energy storage battery pack are connected to the input positive electrode and input negative electrode of the battery management system respectively;

[0045] The output positive electrode and the output negative electrode of the battery management system are also connected to the low-voltage positive DC bus (BUS+) and the low-voltage negative DC bus (BUS-) respectively;

[0046] The input positive pole and the input negative pole of the bidirectional power converter are respectively connected to the low-voltage positive DC bus and the low-voltage negative DC bus. The bidirectional power converter is also connected to the AC input terminal and the AC output terminal.

[0047] The soft start circuit includes a low voltage DC bus capacitor C1, a pre-charge resistor R1, a pre-charge MOS tube Q4, a grounding MOS tube Q3, and a discharge resistor R2;

[0048] One end of the low-voltage DC bus capacitor C1 is connected to the low-voltage positive DC bus, and the other end of the low-voltage DC bus capacitor C1 is connected to one end of the pre-charging resistor R1;

[0049] The other end of the pre-charging resistor R1 is connected to one end of the pre-charging MOS tube Q4, and the other end of the pre-charging MOS tube Q4 is connected to the low-voltage negative DC bus;

[0050] One end of the discharge resistor R2 is connected to the low voltage positive DC bus, and the other end of the discharge resistor R2 is connected to one end of R1;

[0051] One end of the grounded MOS tube Q3 is connected to the other end of R2, and the other end of the grounded MOS tube Q3 is connected to the low-voltage negative DC bus;

[0052] The other end of the grounded MOS tube Q3 is also connected to the input negative electrode of the step-down DCDC converter; the input positive electrode of the step-down DCDC converter is connected to the low-voltage positive DC bus; the step-down DCDC converter is also connected to the DC output terminal.

[0053] The battery management system, the bidirectional power converter and the step-down DCDC converter are also connected via a communication bus.

[0054] In this embodiment, MOS tubes Q3 and Q4 are MOSFETs, and their withstand voltage is greater than the maximum input voltage protection value of the BMS. MOS tubes Q3 and Q4 can be controlled by the BMS or a bidirectional power converter.

[0055] The pre-charging resistor R1 and the discharge resistor R2 are one of cement resistors, metal film resistors, thick film resistors, and wire-wound resistors.

[0056] The communication bus is RS485 communication bus or CAN communication bus.

[0057] Based on the above system, this embodiment also provides a portable energy storage control method, including the following contents:

[0058] When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises slowly.

[0059] After a delay of t1, the grounded MOS tube Q3 is closed; in this embodiment, the delay of t1 is a fixed delay obtained through calibration testing;

[0060] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0061] In this embodiment, the control of MOS tubes Q3 and Q4 can be independently controlled by BMS or bidirectional power converter; or BMS and bidirectional power converter can be controlled simultaneously. If there is a photovoltaic charging module, it can also be controlled by the photovoltaic charging module, BMS, and bidirectional power converter simultaneously.

[0062] Embodiment 2

[0063] The difference between this embodiment and the first embodiment is that in the system of this embodiment, the battery management system includes a current detection resistor Rsense connected to the output negative electrode and the low-voltage negative DC bus.

[0064] The portable energy storage control method of this embodiment includes the following contents:

[0065] When soft start is required, the pre-charge MOS tube Q4 is first controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises slowly.

[0066] The current I of the pre-charge resistor R1 is collected through the current detection resistor Rsense of the BMS R1 ;

[0067] When I R1When the current is less than the set current threshold, the grounding MOS tube Q3 is closed; in this embodiment, the current threshold can be obtained through actual testing.

[0068] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0069] During the entire soft start process, when Q3 is not closed, the current loop is battery positive-Q1-Q2-C1-R1-Q4-battery negative. At this time, the loop current cannot exceed the rated current of Q4.

[0070] When Q3 is closed, the current loop is battery positive-Q1-Q2-C1-Q3-battery negative. At this time, the maximum current should not exceed the rated current value of Q3. Assuming that the rated current of Q3 is 30A and the on-resistance of Q3 is 100mΩ, the current threshold should be less than 30A*100mΩ / R1;

[0071] Assuming that the resistor R1 is 10Ω, when the current through the resistor R1 is less than 0.3A, the current flowing through Q3 will not exceed its rated current.

[0072] Using the current threshold of this embodiment, the pre-charge time is short, and when Q3 is closed, the current will not have the risk of damaging the circuit.

[0073] Embodiment 3

[0074] The difference between this embodiment and the second embodiment is that the method of this embodiment includes the following contents:

[0075] When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises slowly.

[0076] When the voltage V on the resistor R1 is detected R1 When the voltage is less than the set voltage threshold, the grounding MOS tube Q3 is closed; in this embodiment, the voltage threshold can be obtained through actual testing.

[0077] Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

[0078] Embodiment 4

[0079] like Figure 2 As shown, the difference between this embodiment and the first embodiment is that the system in this embodiment further includes a buck-boost DCDC converter.

[0080] The positive input electrode and the negative input electrode of the buck-boost DCDC converter are connected to the photovoltaic positive electrode output terminal pv+ and the photovoltaic negative electrode output terminal pv- respectively;

[0081] The output positive electrode and the output negative electrode of the buck-boost DCDC converter are respectively connected to the input positive electrode and the input negative electrode of the buck DCDC converter;

[0082] The buck-boost DCDC converter is also connected to the communication bus.

[0083] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or the priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A portable energy storage control system, comprising a low voltage positive DC bus, a low voltage negative DC bus and a soft start circuit, characterized in that: The soft start circuit includes a low voltage DC bus capacitor C1, a pre-charge resistor R1, a pre-charge MOS tube Q4, a grounding MOS tube Q3, and a discharge resistor R2; One end of the low-voltage DC bus capacitor C1 is connected to the low-voltage positive DC bus, and the other end of the low-voltage DC bus capacitor C1 is connected to one end of the pre-charging resistor R1; The other end of the pre-charging resistor R1 is connected to one end of the pre-charging MOS tube Q4, and the other end of the pre-charging MOS tube Q4 is connected to the low-voltage negative DC bus; One end of the discharge resistor R2 is connected to the low voltage positive DC bus, and the other end of the discharge resistor R2 is connected to one end of R1; One end of the grounded MOS tube Q3 is connected to the other end of R2, and the other end of the grounded MOS tube Q3 is connected to the low-voltage negative DC bus.

2. The portable energy storage control system according to claim 1, characterized in that: It also includes energy storage battery pack, battery management system, bidirectional power converter and step-down DCDC converter; The positive electrode and negative electrode of the energy storage battery pack are connected to the input positive electrode and input negative electrode of the battery management system respectively; The output positive electrode and the output negative electrode of the battery management system are also connected to the low-voltage positive DC bus and the low-voltage negative DC bus respectively; The input positive pole and the input negative pole of the bidirectional power converter are respectively connected to the low voltage positive DC bus and the low voltage negative DC bus, and the bidirectional power converter is also connected to the AC input terminal and the AC output terminal; The other end of the grounded MOS tube Q3 is also connected to the input negative electrode of the step-down DCDC converter; the input positive electrode of the step-down DCDC converter is connected to the low-voltage positive DC bus; the step-down DCDC converter is also connected to the DC output terminal.

3. The portable energy storage control system according to claim 2, characterized in that: It also includes a communication bus, through which the battery management system, the bidirectional power converter and the step-down DCDC converter are connected.

4. The portable energy storage control system according to claim 2, characterized in that: It also includes a buck-boost DCDC converter; The input positive electrode and the input negative electrode of the buck-boost DCDC converter are connected to the photovoltaic positive electrode output terminal and the photovoltaic negative electrode output terminal respectively; The output positive electrode and the output negative electrode of the buck-boost DCDC converter are respectively connected to the input positive electrode and the input negative electrode of the buck DCDC converter; The buck-boost DCDC converter is also connected to the communication bus.

5. The portable energy storage control system according to claim 2, characterized in that: The withstand voltage values ​​of the pre-charging MOS tube Q4 and the grounding MOS tube Q3 are greater than the maximum input voltage protection value of the battery management system.

6. The portable energy storage control system and control method according to claim 2, characterized in that: The battery management system includes a current detection resistor Rsense connected to the output negative electrode and the low-voltage negative DC bus.

7. A portable energy storage control method, using the system of claim 2, characterized in that: It includes the following: When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises; After a delay of t1, the grounded MOS tube Q3 is closed; Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

8. A portable energy storage control method, using the system of claim 6, characterized in that: It includes the following: When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises; The current I of the pre-charge resistor R1 is collected through the current detection resistor Rsense R1 ; When I R1 When the current is less than the set current threshold, the grounded MOS tube Q3 is closed; Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

9. A portable energy storage control method, using the system of claim 2, characterized in that: It includes the following: When soft start is required, the pre-charge MOS tube Q4 is controlled to be turned on, and the voltage across the low-voltage DC bus capacitor C1 rises; When the voltage V on the resistor R1 is detected R1 When it is less than the set voltage threshold, the grounding MOS tube Q3 is closed; Disconnect the pre-charge MOS tube Q4 and the soft start is completed.

Images