A remote voltage sampling compensation charging pile

Abstract

This invention provides a remote voltage sampling compensation charging pile in the field of charging pile technology, including a charging cabinet and at least one charging gun; the charging cabinet includes a power module, a charger controller, a voltage and current sampling module, a resistor R1, a switch K3, and a switch K4; one end of the power module is connected to switches K3 and K4, and the other end is connected to the voltage and current sampling module; the charging gun is connected to the charger controller, the voltage and current sampling module, and switches K3 and K4 respectively; the resistor R1 is connected to the charger controller and the charging gun; the charger controller is connected to the voltage and current sampling module, switches K3 and K4 respectively. The advantages of this invention are: it greatly improves the voltage sampling accuracy and realizes compensation for the output voltage of the charging gun.

Description

Technical Field

[0001] The present invention relates to the technical field of charging piles, and in particular to a remote voltage sampling and compensation charging pile. Background Art

[0002] A DC charging pile is a special DC device used to directly connect electric vehicles to the AC / DC power grid (power supply), provide DC power to the battery pack of the electric vehicle, replenish energy for the electric vehicle under the management of the on-board BMS system, and is equipped with a control and guidance device to ensure reliable connection between the DC charging column and the electric vehicle and charging safety. At the same time, it integrates functional modules such as human-computer interaction system, fee management system, local and remote communication interface, etc., to facilitate the use and management of DC charging piles.

[0003] A DC charging pile generally consists of a charging cabinet, a charging cable, and a charging gun. The charging gun is inserted into the charging seat of an electric vehicle to charge the electric vehicle. Since the charging seats of electric vehicles of different brands and models are located in different positions, for example, some are located at the front of the vehicle and some are located at the rear of the vehicle, in order to avoid the need to turn around again after parking due to insufficient charging cables, existing DC charging piles are generally equipped with longer charging cables, with common specifications of 5 meters and 7 meters, to ensure that the charging gun can be inserted into the charging seats located at different positions of the electric vehicle.

[0004] When a DC charging pile is charging an electric vehicle, the amount of electricity charged needs to be billed, that is, the voltage needs to be sampled. However, the voltmeter of a traditional DC charging pile is directly connected to the positive and negative poles of the DCDC module inside the charging cabinet for voltage sampling. Due to the long charging cable, when the DCDC module outputs a large current, the actual voltage on the charging station will be lower than the sampled voltage, that is, the voltage sampling is inaccurate, and this part of the loss will be paid by the user.

[0005] The equivalent circuit diagram of a traditional DC charging pile is as follows: Figure 7 As shown, the line loss can be equivalent to the contact resistance r1 and the charging cable internal resistance r2; the contact resistance r1 includes the contact resistance from the DCDC module to the copper busbar (fixed with studs), the contact resistance from the copper busbar to the contactor (fixed with bolts), the contact resistance of the contactor contacts, the contact resistance from the contactor to the copper busbar (fixed with bolts), and the contact resistance from the copper busbar to the charging cable connector (fixed with bolts); the charging cable internal resistance r2 includes the wire internal resistance from the DCDC module to the copper busbar, the copper busbar internal resistance, the charging cable internal resistance, etc.

[0006] When the DC charging pile outputs 250A current, taking a 7-meter charging cable as an example, the wire diameter of the charging cable is 80mm2, and the resistivity of copper is 0.0185Ω*mm2 / m at 30℃. The calculated internal resistance of the unilateral charging cable is 1.619mΩ. Under 250A conditions, the voltage drop of the positive and negative charging cables = 1.619mΩ*250A*2 = 0.8V, and the power consumption of the charging cable = 0.8V*250A = 200W. Assuming that the contact resistance r1 value is 2.4mΩ, under 250A conditions, the voltage drop is 2.4mΩ*250A = 0.6V, and the power consumption caused by the contact resistance = 150W. That is, under 250A conditions, the total voltage drop of the 7-meter charging cable reaches 0.8+0.6=1.4V, and the total power consumption reaches 200+150=350W.

[0007] If it is expanded to super charging, the wire diameter of the charging cable is still 80mm2, liquid cooling is used, and the current reaches 600A. The total voltage drop can reach (1.619*2+2.4)*600=3.383V, and the power consumption reaches 3.383*600=2029.8W.

[0008] Taking a 7-meter charging cable as an example, the power consumption caused by contact resistance and cable internal resistance reaches 350W at 250A, and at 600A, the power consumption reaches more than 2000W.

[0009] Therefore, how to provide a remote voltage sampling compensation charging pile to improve the voltage sampling accuracy and compensate the output voltage of the charging gun has become an urgent problem to be solved. Summary of the invention

[0010] The technical problem to be solved by the present invention is to provide a remote voltage sampling compensation charging pile to improve the voltage sampling accuracy and compensate the output voltage of the charging gun.

[0011] The present invention is implemented as follows: A remote voltage sampling compensation charging pile, characterized in that: it includes a charging cabinet and at least one charging gun; the charging cabinet includes a power module, a charger controller, a voltage and current sampling module, a resistor R1, a switch K3 and a switch K4;

[0012] One end of the power module is connected to the switch K3 and the switch K4, and the other end is connected to the voltage and current sampling module; the charging gun is respectively connected to the charger controller, the voltage and current sampling module, the switch K3 and the switch K4; the resistor R1 is connected to the charger controller and the charging gun; the charger controller is respectively connected to the voltage and current sampling module, the switch K3 and the switch K4.

[0013] Further, the charging gun includes a terminal DC+, a terminal DC-, a terminal PE, a terminal S+, a terminal S-, a terminal CC1, a terminal A+ and a terminal A-;

[0014] The terminal DC+ and the terminal DC- are both connected to the voltage and current sampling module; the terminal PE is grounded; the terminal S+, the terminal S- and the terminal CC1 are all connected to the charger controller; the terminal A+ is connected to the switch K3; and the terminal A- is connected to the switch K4.

[0015] Further, the power module includes an ACDC module, a DCDC module, an auxiliary power supply, a switch K5, a switch K6 and a switch K7;

[0016] One end of the ACDC module is connected to the DCDC module, and the other end is connected to the auxiliary power supply through switch K5, switch K6 and switch K7; the DCDC module is connected to the voltage and current sampling module; the auxiliary power supply is connected to switch K3 and switch K4.

[0017] Further, the voltage and current sampling module includes a voltmeter V, an ammeter A, a discharge circuit, a fuse F1, a switch K1, a switch K2, a switch Ka, a switch Kb, a resistor Ra, a resistor Rb, a resistor Rc, a resistor Rd, a positive sampling line and a negative sampling line;

[0018] One end of the ammeter A is connected to the positive electrode of the DCDC module, and the other end is connected to the resistor Ra, the discharge circuit and the switch K1; one end of the fuse F1 is connected to the switch K1, and the other end is connected to the terminal DC+; one end of the switch K2 is connected to the negative electrode of the DCDC module, the resistor Rd and the discharge circuit, and the other end is connected to the terminal DC-; one end of the positive sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC+; one end of the negative sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC-; one end of the switch Ka is connected to the voltmeter V, and the other end is connected to the resistor Rb; one end of the switch Kb is connected to the voltmeter V, and the other end is connected to the resistor Rc;

[0019] The resistors Ra, Rb, Rc and Rd are all connected to the DCDC module; the voltmeter V, ammeter A, switch K1, switch K2, switch Ka and switch Kb are all connected to the charger controller.

[0020] Furthermore, the diameters of the positive sampling line and the negative sampling line are both 0.75 mm. 2 .

[0021] Furthermore, the resistance value of the resistor Ra is greater than the resistance value of the resistor Rb, and the resistance value of the resistor Rd is greater than the resistance value of the resistor Rc.

[0022] The advantages of the present invention are:

[0023] 1. By setting a positive sampling line and a negative sampling line to connect the voltmeter V and the terminal DC+ and the terminal DC- respectively, that is, the voltmeter V directly samples the voltage from the terminal DC+ and the terminal DC- of the charging gun. Since the impedance of the voltage sampling circuit composed of the terminal DC+, the terminal DC- and the electric vehicle is very large (at least 1MΩ), the internal resistance of the sampling line (positive sampling line and negative sampling line) can be ignored, that is, the voltage drop caused by the traditional charging cable is overcome. Compared with the traditional voltage sampling from the positive and negative poles of the DCDC module, the voltage sampling accuracy is greatly improved.

[0024] 2. The charging pile needs to be tested for insulation before charging the electric vehicle. By setting switches K1, K2, Ka and Kb, when switches K1 and K2 are disconnected, switches Ka and Kb are also disconnected, so that the voltage sampling of the DCDC module comes from resistors Ra and Rd respectively, avoiding the positive sampling line and the negative sampling line being suspended when not charging; when switches K1 and K2 are closed, switches Ka and Kb are also closed. Since Ra>Rb and Rd>Rc, the voltage sampling of the DCDC module comes from resistors Rb and Rc, that is, the DC+ and DC- terminals of the charging gun, and the output voltage is adjusted with the sampled voltage signal as feedback to compensate for the output voltage of the charging gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0026] Figure 1 It is a circuit principle block diagram of a remote voltage sampling compensation charging pile of the present invention.

[0027] Figure 2 It is a circuit principle block diagram of the power module of the present invention.

[0028] Figure 3 It is a circuit principle block diagram of the charger controller of the present invention.

[0029] Figure 4 It is a circuit diagram of the charging gun of the present invention.

[0030] Figure 5 It is a circuit diagram of the voltage and current sampling module of the present invention.

[0031] Figure 6 It is a circuit diagram of a remote voltage sampling compensation charging pile of the present invention.

[0032] Figure 7 It is the equivalent circuit diagram of a traditional DC charging pile. DETAILED DESCRIPTION

[0033] The technical solution in the embodiments of the present application has the following general idea: by transferring the voltage sampling point from the positive and negative poles of the DCDC module to the terminal DC+ and terminal DC- of the charging gun, the voltage sampling accuracy is improved; by setting switches K1, K2, Ka and Kb, when switches K1 and K2 are closed, switches Ka and Kb are also closed. Since Ra>Rb, Rd>Rc, the voltage sampling of the DCDC module comes from resistors Rb and Rc, i.e., terminals DC+ and DC- of the charging gun, respectively, and the output voltage is adjusted based on the sampled voltage signal as feedback to compensate for the output voltage of the charging gun.

[0034] Please refer to Figures 1 to 7 As shown, a preferred embodiment of a remote voltage sampling compensation charging pile of the present invention includes a charging cabinet and at least one charging gun; the charging cabinet includes a power module, a charger controller, a voltage and current sampling module, a resistor R1, a switch K3 and a switch K4; the power module is used to provide output power to the charging gun; the charger controller is used to control the operation of the charging cabinet. In specific implementation, it is sufficient to select a controller that can realize this function from the prior art, and it is not limited to any model; the voltage and current sampling module is used to transmit the power of the power module to the charging gun, and to sample the voltage and current; the resistor R1 is a voltage detection point;

[0035] One end of the power module is connected to the switch K3 and the switch K4, and the other end is connected to the voltage and current sampling module; the charging gun is respectively connected to the charger controller, the voltage and current sampling module, the switch K3 and the switch K4; the resistor R1 is connected to the charger controller and the charging gun; the charger controller is respectively connected to the voltage and current sampling module, the switch K3 and the switch K4.

[0036] The charging gun includes a terminal DC+, a terminal DC-, a terminal PE, a terminal S+, a terminal S-, a terminal CC1, a terminal A+ and a terminal A-; the terminal DC+ is used to connect a DC positive power supply, the terminal DC- is used to connect a DC negative power supply, the terminal PE is used for grounding, the terminal S+ is used to connect a charging communication line CAN-H, the terminal S- is used to connect a charging communication line CAN-L, and the terminal CC1 is used to transmit a charging connection confirmation signal; the terminal A+ is used to connect the positive pole of the auxiliary power supply, and the terminal A- is used to connect the negative pole of the auxiliary power supply;

[0037] The terminal DC+ and the terminal DC- are both connected to the voltage and current sampling module; the terminal PE is grounded; the terminal S+, the terminal S- and the terminal CC1 are all connected to the charger controller; the terminal A+ is connected to the switch K3; and the terminal A- is connected to the switch K4.

[0038] The power module includes an ACDC module, a DCDC module, an auxiliary power supply, a switch K5, a switch K6 and a switch K7;

[0039] One end of the ACDC module is connected to the DCDC module, and the other end is connected to the auxiliary power supply through switch K5, switch K6 and switch K7; the DCDC module is connected to the voltage and current sampling module; the auxiliary power supply is connected to switch K3 and switch K4; the switch K5, switch K6 and switch K7 are all connected to the charger controller.

[0040] The voltage and current sampling module includes a voltmeter V (or a DC energy meter), an ammeter A, a discharge circuit, a fuse F1, a switch K1, a switch K2, a switch Ka, a switch Kb, a resistor Ra, a resistor Rb, a resistor Rc, a resistor Rd, a positive sampling line and a negative sampling line;

[0041] One end of the ammeter A is connected to the positive electrode of the DCDC module, and the other end is connected to the resistor Ra, the discharge circuit and the switch K1; one end of the fuse F1 is connected to the switch K1, and the other end is connected to the terminal DC+; one end of the switch K2 is connected to the negative electrode of the DCDC module, the resistor Rd and the discharge circuit, and the other end is connected to the terminal DC-; one end of the positive sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC+; one end of the negative sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC-; that is, the positive sampling line and the negative sampling line are crimped together with the pole of the charging gun; one end of the switch Ka is connected to the voltmeter V, and the other end is connected to the resistor Rb; one end of the switch Kb is connected to the voltmeter V, and the other end is connected to the resistor Rc;

[0042] The resistors Ra, Rb, Rc and Rd are all connected to the DCDC module; the voltmeter V, ammeter A, switch K1, switch K2, switch Ka and switch Kb are all connected to the charger controller.

[0043] The diameters of the positive sampling line and the negative sampling line are both 0.75 mm 2 , with a withstand voltage of more than 1000V, and is filled in separate strands.

[0044] The resistance value of the resistor Ra is greater than the resistance value of the resistor Rb, and the resistance value of the resistor Rd is greater than the resistance value of the resistor Rc.

[0045] Working principle of the present invention:

[0046] The charging gun is connected to a charging base of an electric vehicle. The charger controller disconnects switch K1, switch K2, switch Ka and switch Kb for insulation detection, and then closes switch K1, switch K2, switch Ka and switch Kb. The voltmeter V collects the voltage output by the charging gun through a positive sampling line and a negative sampling line, and feeds the collected voltage back to a DCDC module through the switch Ka, switch Kb, resistor Rb and resistor Rc. The DCDC module compensates the voltage output by the charging gun based on the fed-back voltage.

[0047] In summary, the advantages of the present invention are:

[0048] 1. By setting a positive sampling line and a negative sampling line to connect the voltmeter V and the terminal DC+ and the terminal DC- respectively, that is, the voltmeter V directly samples the voltage from the terminal DC+ and the terminal DC- of the charging gun. Since the impedance of the voltage sampling circuit composed of the terminal DC+, the terminal DC- and the electric vehicle is very large (at least 1MΩ), the internal resistance of the sampling line (positive sampling line and negative sampling line) can be ignored, that is, the voltage drop caused by the traditional charging cable is overcome. Compared with the traditional voltage sampling from the positive and negative poles of the DCDC module, the voltage sampling accuracy is greatly improved.

[0049] 2. The charging pile needs to be tested for insulation before charging the electric vehicle. By setting switches K1, K2, Ka and Kb, when switches K1 and K2 are disconnected, switches Ka and Kb are also disconnected, so that the voltage sampling of the DCDC module comes from resistors Ra and Rd respectively, avoiding the positive sampling line and the negative sampling line being suspended when not charging; when switches K1 and K2 are closed, switches Ka and Kb are also closed. Since Ra>Rb and Rd>Rc, the voltage sampling of the DCDC module comes from resistors Rb and Rc, that is, the DC+ and DC- terminals of the charging gun, and the output voltage is adjusted with the sampled voltage signal as feedback to compensate for the output voltage of the charging gun.

[0050] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A remote voltage sampling compensation charging pile, characterized in that: It includes a charging cabinet and at least one charging gun; the charging cabinet includes a power module, a charger controller, a voltage and current sampling module, a resistor R1, a switch K3 and a switch K4; One end of the power module is connected to the switch K3 and the switch K4, and the other end is connected to the voltage and current sampling module; the charging gun is connected to the charger controller, the voltage and current sampling module, the switch K3 and the switch K4 respectively; the resistor R1 is connected to the charger controller and the charging gun; the charger controller is connected to the voltage and current sampling module, the switch K3 and the switch K4 respectively; The charging gun includes a terminal DC+, a terminal DC-, a terminal PE, a terminal S+, a terminal S-, a terminal CC1, a terminal A+ and a terminal A-; The terminals DC+ and DC- are connected to the voltage and current sampling module; the terminal PE is grounded; the terminals S+, S- and CC1 are connected to the charger controller; the terminal A+ is connected to the switch K3; the terminal A- is connected to the switch K4; The power module includes an ACDC module, a DCDC module, an auxiliary power supply, a switch K5, a switch K6 and a switch K7; One end of the ACDC module is connected to the DCDC module, and the other end is connected to the auxiliary power supply through switch K5, switch K6 and switch K7; the DCDC module is connected to the voltage and current sampling module; the auxiliary power supply is connected to switch K3 and switch K4; The voltage and current sampling module includes a voltmeter V, an ammeter A, a discharge circuit, a fuse F1, a switch K1, a switch K2, a switch Ka, a switch Kb, a resistor Ra, a resistor Rb, a resistor Rc, a resistor Rd, a positive sampling line and a negative sampling line; One end of the ammeter A is connected to the positive electrode of the DCDC module, and the other end is connected to the resistor Ra, the discharge circuit and the switch K1; one end of the fuse F1 is connected to the switch K1, and the other end is connected to the terminal DC+; one end of the switch K2 is connected to the negative electrode of the DCDC module, the resistor Rd and the discharge circuit, and the other end is connected to the terminal DC-; one end of the positive sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC+; one end of the negative sampling line is connected to the voltmeter V, and the other end is connected to the terminal DC-; one end of the switch Ka is connected to the voltmeter V, and the other end is connected to the resistor Rb; one end of the switch Kb is connected to the voltmeter V, and the other end is connected to the resistor Rc; The resistors Ra, Rb, Rc and Rd are all connected to the DCDC module; the voltmeter V, ammeter A, switch K1, switch K2, switch Ka and switch Kb are all connected to the charger controller.

2. A remote voltage sampling compensation charging pile as claimed in claim 1, characterized in that: The diameters of the positive sampling line and the negative sampling line are both 0.75 mm 2 .

3. A remote voltage sampling compensation charging pile as claimed in claim 1, characterized in that: The resistance value of the resistor Ra is greater than the resistance value of the resistor Rb, and the resistance value of the resistor Rd is greater than the resistance value of the resistor Rc.

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