Solar charging system of new energy automobile

Abstract

The utility model discloses a solar charging system for a new energy automobile. The system comprises a vehicle-mounted solar battery assembly, a low-voltage bus, a storage battery, a high-voltage bus and a power battery pack, wherein the solar battery assembly is connected with a charging controller through an MPPT (maximum power point tracking) solar battery controller; the input end of a one-way DC-DC converter of the charging controller is connected with the MPPT solar cell controller, and the output end of the one-way DC-DC converter of the charging controller is connected with the storage battery A low-voltage port of the bidirectional DC-DC converter is connected with the low-voltage bus, and a high-voltage port is connected with the power battery pack through the high-voltage bus; and the charging controller is also connected with a control unit. The system has the advantages that the output of the vehicle-mounted solar battery component is optimized, the charging stability of the power battery is improved, and the overall energy utilization efficiency of a new energy automobile is improved, so that a more stable charging process of the power battery can be provided, the charging stability and reliability are ensured, the cruising ability of the electric automobile is prolonged, and the service life of the power battery is prolonged; and the maintenance cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a new energy automobile charging technology especially a new energy automobile solar charging system. BACKGROUND

[0002] With the increasingly severe global energy crisis and environmental problems, new energy vehicles, especially electric vehicles, have been widely applied and developed. In order to improve the energy utilization efficiency and endurance of new energy vehicles, solar charging systems have gradually become an important auxiliary energy solution; through the vehicle-mounted solar cell assembly, the power battery is charged, which not only can prolong the endurance mileage of the electric vehicle, but also can provide continuous power supply for the vehicle in the parking state.

[0003] However, there are some technical problems in the practical application of the vehicle-mounted solar charging system. First, due to the relatively low power generation of the vehicle-mounted solar cell assembly and the large charging demand of the power battery, the output power of the solar cell is difficult to directly meet the charging demand of the power battery. Secondly, the power generation of the solar cell is affected by the external environment such as weather and light, and the instability phenomenon of power generation fluctuation and intermittent power supply is easy to appear, which has an adverse effect on the charging process of the power battery, which may lead to low charging efficiency or incomplete charging of the power battery, and further affect the endurance and power performance of the electric vehicle. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide a new energy automobile solar charging system which can optimize the output of the vehicle-mounted solar cell assembly, improve the charging stability of the power battery, and improve the overall energy utilization efficiency of the new energy vehicle.

[0005] In order to solve the above technical problems, the new energy automobile solar charging system of the utility model comprises a vehicle-mounted solar cell assembly, a low-voltage bus, a storage battery, a high-voltage bus and a power battery pack, the solar cell assembly is connected with a charging controller through an MPPT solar cell controller, the charging controller comprises a unidirectional DC-DC converter and a bidirectional DC-DC converter, the input end of the unidirectional DC-DC converter is connected with the MPPT solar cell controller, the output end of the unidirectional DC-DC converter is connected with the storage battery through the low-voltage bus, the low-voltage port of the bidirectional DC-DC converter is connected with the low-voltage bus, the high-voltage port of the bidirectional DC-DC converter is connected with the power battery pack through the high-voltage bus, and the charging controller is further connected with a control unit which can control the running state of the charging controller.

[0006] The bidirectional DC-DC converter has a Boost circuit capable of charging the power battery by the power supply of the battery and the unidirectional DC-DC converter under the control of the control unit when the battery has sufficient power, and the Boost circuit is also capable of being closed under the control of the control unit when the battery has insufficient power.

[0007] The bidirectional DC-DC converter also has a Buck circuit capable of being started when there is a power shortage fluctuation in the power supply of the low-voltage bus by the unidirectional DC-DC converter (4).

[0008] The sufficient battery power state is that the power is between 90-100% of the total capacity of the battery, and the insufficient battery power state is that the power is between 20-80% of the total capacity of the battery.

[0009] The vehicle-mounted solar cell assembly comprises a solar sunroof and a solar cell module.

[0010] The solar cell module is installed on the roof, the engine cover, the rear window glass or the trunk of the vehicle body.

[0011] The utility model has the advantages of:

[0012] The MPPT solar controller ensures that the solar cell module is in the best working state, the unidirectional DC-DC converter realizes the power supply of the low-voltage bus and the charging of the battery, and the bidirectional DC-DC converter is arranged between the low-voltage bus and the high-voltage bus, so that the bidirectional power flow function is realized between the power battery pack and the battery. When the solar charging system works, the solar cell module stores the redundant power into the battery under the premise of meeting the power consumption of the low-voltage bus, and when the power of the battery reaches the predetermined sufficient capacity, the power battery pack is charged. Through this way, the problem of unstable charging of the power battery pack caused by the intermittent fluctuation of the solar cell module is solved. When the battery is charging the power battery pack, the solar cell module charges the battery when the power of the battery decreases to the insufficient capacity state. At the same time, when the power supply of the low-voltage bus by the unidirectional DC-DC converter has a power shortage fluctuation, the Buck circuit in the bidirectional DC-DC converter is started in time to ensure the stability of the power supply of the low-voltage bus, thereby optimizing the output of the vehicle-mounted solar cell assembly, improving the charging stability of the power battery, improving the overall energy utilization efficiency of the new energy vehicle, and effectively coping with the fluctuation of the solar cell assembly, providing a more stable power battery charging process, ensuring the charging stability and reliability, prolonging the endurance of the electric vehicle and the service life of the power battery, and reducing the maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The system principle diagram of the new energy automobile solar charging system;

[0014] Figure 2 The circuit diagram of the charging controller in the utility model;

[0015] Figure 3 The circuit diagram of the control unit in the utility model;

[0016] Figure 4 The topology structure diagram of the Buck circuit;

[0017] Figure 5 The circuit diagram of the feedback loop in the utility model. DETAILED DESCRIPTION

[0018] The new energy automobile solar charging system of the utility model will be further explained in detail below in combination with the drawings and specific embodiments.

[0019] As Figure 1 shown, the new energy automobile solar charging system of the utility model, including vehicle-mounted solar cell assembly 1, MPPT solar cell controller 2, charging controller 3, unidirectional DC-DC converter 4, bidirectional DC-DC converter 5, low-voltage bus 6, storage battery 7, high-voltage bus 8, power battery pack 9 and control unit 10, solar cell assembly 1 is connected with charging controller 3 through MPPT solar cell controller 2, wherein, charging controller 3 contains two modules (as Figure 2 shown) of unidirectional DC-DC converter 4 and bidirectional DC-DC converter 5; the input end of unidirectional DC-DC converter 4 is connected with MPPT solar cell controller 2, the output end of unidirectional DC-DC converter 4 is connected with storage battery 7 through low-voltage bus 6, the low-voltage port of bidirectional DC-DC converter 5 is connected with low-voltage bus 6, the high-voltage port of bidirectional DC-DC converter 5 is connected with power battery pack 9 through high-voltage bus 8, that is, bidirectional DC-DC converter is arranged between low-voltage bus and high-voltage bus; as shown in the drawing, bidirectional DC-DC converter 5 has Boost voltage boosting circuit, Boost voltage boosting circuit can control power supply through storage battery and unidirectional DC-DC converter 4 to charge power battery 9 when the electric quantity of storage battery is sufficient, Boost voltage boosting circuit can also be controlled to be closed by control unit when the electric quantity of storage battery is insufficient, at the same time, bidirectional DC-DC converter 5 also has Buck circuit that can be started when unidirectional DC-DC converter 4 appears power supply shortage fluctuation to low-voltage bus; control unit 10 (as Figure 3The control unit 10 is connected with the charging controller 3 and controls the running state of the charging controller 3 through logical instructions, and the control unit 10 is connected with the storage battery 7 and monitors the remaining power SOC state (hereinafter referred to as SOC, State Of Charge) of the storage battery 7.

[0020] Further, the sufficient power state (SOC1) of the storage battery is between 90-100% of the total capacity of the storage battery, and the insufficient power state (SOC2) of the storage battery is between 20-80% of the total capacity of the storage battery.

[0021] Still further, the vehicle-mounted solar cell module 1 comprises a solar sunroof and a solar cell module, wherein the solar cell module can be installed on the roof, the engine hood, the rear window glass or the trunk of the vehicle body.

[0022] The bidirectional DC-DC converter mentioned in the utility model is a bidirectional DC-DC converter which realizes bidirectional operation by changing the direction of current according to actual needs while keeping the input and output voltage polarity unchanged. In fact, bidirectional energy transmission can also be realized by connecting two unidirectional DC-DC converters in anti-parallel connection. Since a diode is generally needed on the main power transmission path of the unidirectional converter, the flow direction of energy of a single converter is still unidirectional, and such a connection mode will make the system bulky, heavy, low in efficiency and high in cost. Therefore, the best way is to realize bidirectional energy flow through a converter, and the bidirectional DC-DC is realized by changing the unidirectional switch and diode into a bidirectional switch and adding reasonable control to realize bidirectional energy flow.

[0023] Suppose that the two-phase interleaved Buck circuit works under ideal conditions, the influence of the parasitic parameters of the components of the converter is ignored, the inductances of the two-phase bridge arms are equal, the duty cycles of the two phases are equal, the phase difference of the driving signals is 180°, the input voltage is Udc, and the terminal voltage of the storage battery is Ub, and the topology structure is as shown in Figure 4 It mainly comprises switch elements S1 and S2, diodes D1 and D2, inductors L1 and L2, a capacitor C and a feedback loop. Figure 5 The general feedback loop (as shown in

[0024] The working process of the Buck converter can be divided into two parts:

[0025] 1) Switch (transistor) conduction: diode cutoff; inductance current linearly increases and stores energy; capacitor charges and stores energy; output voltage Vo.

[0026] 2) Switch (transistor) turn-off: diode conduction; inductance releases energy; capacitor discharges; output Vo.

[0027] When the switch element S1 is turned on, the voltage V1 is equal to the output voltage Vdc, the transistor is in reverse blocking state, the current flows through the inductor L1, and the current increases linearly. After filtering through the capacitor C, the output current Io and the output voltage Vo are generated. The sampling network R1 and R2 sample the output voltage Vo to obtain the voltage signal Vs, and compare and amplify the signal with the reference voltage Vref to obtain the signal. The signal Vea and the linearly rising triangular wave signal Vtr are compared. When Vea=Vtr, the control signal Vwm and VG jump to low, and the switch element S1 is cut off. At this time, in order to keep the current IL1 of the inductor L1 unchanged, the magnetic field in the inductor L1 will change the polarity of the voltage across the inductor L1. At this time, the diode D1 bears the forward bias, and the current ID1 flows through. If the capacitor C is in the discharge state, it is beneficial to keep the output current Io and the output voltage Vo constant. The state of the switch element being cut off is maintained until the beginning of the next period, and when the condition is met again, the switch element M1 is turned on again, and the above process is repeated.

[0028] The working principle is as follows:

[0029] In the parking and power-off state, the control unit issues an instruction to enable the unidirectional DC-DC converter 4 to supply power to the low-voltage bus 6 to realize charging of the battery pack 1 to the storage battery 7; when the storage battery reaches the SOC1 state, the Boost circuit in the bidirectional DC-DC converter 5 is started, at this time the low-voltage bus is supplied by the storage battery and the unidirectional DC-DC converter 4, and charging of the power battery 9 is realized through the Boost circuit; as the charging proceeds, when the storage battery reaches SOC2, the control unit closes the Boost circuit, at this time the unidirectional DC-DC converter 4 charges the storage battery.

[0030] When the vehicle is powered on, the unidirectional DC-DC converter 4 supplies power to the low-voltage bus 6 to reduce the power consumption of the storage battery and the power battery; at the same time, the Buck circuit in the bidirectional DC-DC converter 5 is in hot standby state, when the unidirectional DC-DC converter 4 supplies power to the low-voltage bus appears power shortage fluctuation, the Buck circuit in the bidirectional DC-DC converter starts immediately to ensure the stability of the low-voltage bus power supply.

[0031] It can be seen from the principle that, when the solar charging system is working, the solar cell module stores the redundant power into the storage battery under the premise of meeting the power consumption of the low-voltage bus, and when the power of the storage battery reaches the predetermined capacity (close to saturation) state SOC1, the Boost module in the bidirectional DC-DC converter is started to charge the power battery pack. Through this way, the problem of unstable charging of the power battery pack caused by the intermittent fluctuation of the solar cell module is solved. With the charging of the storage battery to the power battery pack, when the power of the storage battery decreases to the SOC2 state, the Boost module in the DC-DC converter is closed, at this time, the solar cell module charges the storage battery, until the storage battery reaches the SOC1 state again, and the Boost module in the DC-DC converter is started again to charge the power battery pack.

[0032] At the same time, the Buck circuit in the bidirectional DC-DC converter 5 is set to a hot standby start mode, and when the single-direction DC-DC converter 4 appears power shortage fluctuation in supplying power to the low-voltage bus, the Buck circuit in the bidirectional DC-DC converter is started in time to ensure the stability of the low-voltage bus power supply.

Claims

1. A new energy automobile solar charging system, comprising a vehicle-mounted solar cell assembly (1), a low-voltage bus (6), a storage battery (7), a high-voltage bus (8) and a power battery pack (9), characterized in that: The solar cell module (1) is connected with a charge controller (3) through an MPPT solar cell controller (2), the charge controller (3) comprises a unidirectional DC-DC converter (4) and a bidirectional DC-DC converter (5), the input end of the unidirectional DC-DC converter (4) is connected with the MPPT solar cell controller (2), the output end of the unidirectional DC-DC converter (4) is connected with a storage battery (7) through a low-voltage bus (6), the low-voltage port of the bidirectional DC-DC converter (5) is connected with the low-voltage bus (6), the high-voltage port of the bidirectional DC-DC converter (5) is connected with a power battery pack (9) through a high-voltage bus (8), and the charge controller (3) is further connected with a control unit (10) capable of controlling the running state of the charge controller (3); The bidirectional DC-DC converter (5) has a Boost circuit, the Boost circuit can be controlled by the control unit to charge the power battery pack (9) through the power supply of the storage battery and the unidirectional DC-DC converter (4) when the storage battery has sufficient power, and the Boost circuit can also be controlled by the control unit to be closed when the storage battery has insufficient power. The bidirectional DC-DC converter (5) also has a Buck circuit capable of starting when the unidirectional DC-DC converter (4) has power shortage fluctuation in supplying power to the low-voltage bus.

2. The new energy vehicle solar charging system according to claim 1, characterized in that: The sufficient storage battery power state is that the power is between 90-100% of the total capacity of the storage battery, and the insufficient storage battery power state is that the power is between 20-80% of the total capacity of the storage battery.

3. The new energy vehicle solar charging system according to any one of claims 1-2, characterized in that: The vehicle-mounted solar cell module (1) comprises a solar sunroof and a solar cell module.

4. The new energy vehicle solar charging system according to claim 3, characterized in that: The solar cell module is installed on the roof, engine cover, rear window glass or trunk of the vehicle body.

Images