Power supply system, vehicle, power conversion system and method

Abstract

A power supply system is provided that includes a solar panel, a first battery, a second battery, a first converter, a second converter, and a switching device. The solar panel generates power at a first voltage. The first battery stores power at a second voltage. The second battery stores power at a third voltage. In a first mode of operation, the switching device transfers power from the solar panel to the first battery. The first converter converts power from the first voltage to the second voltage. In a second mode of operation, the switching device transfers power from the first battery to the second battery. The first converter converts power from the second voltage to the first voltage. The second converter converts the first voltage to the third voltage.

Description

[Technical field]

[0001] The present invention relates to a power supply system. The present invention further relates to a vehicle including a power supply system. Furthermore, the present invention relates to a power conversion system and a power supply method. [Background technology]

[0002] The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 848620.

[0003] To provide an environmentally friendly mode of transportation, electric vehicles are equipped with solar panels that power the vehicle, making it independent of electricity from the power grid or, in the case of hybrid vehicles, electricity generated by an internal combustion engine. Electricity generated by solar panels is an environmentally friendly source of energy as it does not produce pollutants such as carbon dioxide, a greenhouse gas.

[0004] Electrical power is used by various systems in a vehicle. Some systems, such as the drive system that powers the vehicle, require high voltage electrical power. Other systems, such as the on-board computer and lighting systems, require low voltage electrical power.

[0005] Solar panels are designed to provide power at a specific voltage. However, the voltage provided by the solar panels is usually different from the voltage required by the vehicle's systems. The voltage generated by the solar panels is different from the high voltage required for the drive system and the low voltage required for the on-board computer.

[0006] Since different voltages of power are required, the power supply system of the vehicle needs to be able to convert power from one voltage to another. A known power supply system is shown in US Patent Application No. US2015 / 0280487. The known power supply system has a solar panel, a low voltage battery, and a high voltage battery. The solar panel supplies power to the low voltage battery. When the voltage of the high voltage battery becomes too low, the power from the low voltage battery is boosted to the high voltage of the high voltage battery via a buck-boost converter to charge the high voltage battery. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent Application No. US2015 / 0280487 Summary of the Invention [Problem to be solved by the invention]

[0008] A problem with known power supply systems is that there is a large energy loss as the power is converted from the solar panel voltage to the low voltage battery voltage and then from the low voltage battery voltage to the high voltage battery voltage.

[0009] It is an object of the present invention to provide an improved power supply system, or at least to provide an alternative. [Means for solving the problem]

[0010] The object of the present invention is achieved by a power supply system including a solar panel, a first battery, a second battery, a first converter, a second converter, and a switching device. The solar panel is for generating power at a first voltage. The first battery is for storing power at a second voltage. The second battery is for storing power at a third voltage. The first converter has a first terminal and a second terminal. The switching device is adapted to transfer power in a first operation mode and a second operation mode. In the first operation mode, the switching device is adapted to transfer power from the solar panel to a first terminal of the first converter and from the second terminal of the first converter to the first battery. The first converter is adapted to convert power from the solar panel from a first voltage at the first terminal to a second voltage at the second terminal. In a second mode of operation, the switching device is adapted to transfer power from the first battery to the second terminal of the first converter, from the first terminal of the first converter to the second converter, and from the second converter to the second battery. The first converter is adapted to convert power from the first battery from a second voltage at the second terminal to a first voltage at the first terminal. The second converter is adapted to convert power from the first battery from the first voltage to a third voltage.

[0011] The inventors have discovered that by using the first terminal as the input of the first converter and the second terminal as the output in a first mode of operation, and by using the second terminal as the input of the first converter and the first terminal as the output in a second mode of operation, the first converter can convert a first voltage to a second voltage and vice versa. By using the first converter to convert a first voltage at the first terminal to a second voltage at the second terminal in a first mode of operation, and to convert a second voltage at the second terminal to a first voltage at the first terminal in a second mode of operation, a simple type of converter can be used as the first converter. For example, the first converter is a boost converter adapted to increase the voltage from the second terminal to the first terminal. In another example, the first converter is a buck converter adapted to decrease the voltage from the first terminal to the second terminal.

[0012] Increasing the voltage is also called boosting the voltage. Reducing the voltage is also called stepping down the voltage.

[0013] By providing the first converter and the second converter, the voltage is converted in two stages from the second voltage via the first voltage to the third voltage. Converting from the second voltage to the third voltage in two stages is more efficient than converting from the second voltage to the third voltage in one stage. As a result, the power supply system can efficiently store the power generated by the solar panel in the first battery and efficiently charge the second battery with the power from the first battery.

[0014] A solar panel, such as a solar cell or photocell, is any suitable device capable of converting light into electricity using the photovoltaic effect. The solar panel may be, for example, an amorphous silicon solar panel, a gallium arsenide germanium solar panel, a monocrystalline solar panel, an organic solar panel, or a thin-film solar panel. The solar panel may, for example, include multiple sub-panels electrically connected to each other. The solar panel may, for example, have a flat, curved and / or double curved surface and receive light for generating electricity. For example, the solar panel may cover at least a portion of a rooftop of a vehicle.

[0015] The first battery is any type of suitable battery for storing power at the second voltage. For example, the first battery may include a nickel iron battery, a lithium ion battery, a lithium ion polymer battery, or a nickel metal hydride battery. The first battery may be a secondary battery capable of receiving power in a first operating mode and providing power in a second operating mode. The first battery may include, for example, multiple batteries electrically connected together to obtain a desired voltage of the first battery or a desired electrical capacity of the first battery.

[0016] The second battery is any type of battery suitable for storing power at a third voltage. For example, the second battery includes a nickel iron battery, a lithium ion battery, a lithium ion polymer battery, or a nickel metal hydride battery, etc. The second battery is, for example, a secondary battery that can receive power in a second operating mode and provide power in another operating mode. The second battery includes, for example, a plurality of batteries electrically connected to each other to obtain a desired voltage of the second battery or a desired electrical capacity of the second battery. The second battery is, for example, the same type of battery as the first battery, but adapted to operate at a third voltage instead of the second voltage. The second battery has a larger electrical capacity than the first battery, a smaller electrical capacity than the first battery, or a similarly large electrical capacity to the first battery.

[0017] In one embodiment, the first converter is adapted to step down a first voltage at the first terminal to a second voltage at the second terminal in a first operating mode, and to step up the second voltage at the second terminal to the first voltage at the first terminal in a second operating mode.

[0018] According to this embodiment, the first converter is adapted to transfer power from a first terminal to a second terminal in a first operating mode. The first converter reduces the voltage of the power from a first voltage at the first terminal to a second voltage at the second terminal. The first converter is, for example, a step-down converter. In a second operating mode, the first converter transfers power from the second terminal to the first terminal. In the second operating mode, by transferring power in a reverse direction compared to the first operating mode, the first converter can increase the voltage of the power from a second voltage at the second terminal to a first voltage at the first terminal.

[0019] In one embodiment, the switching device is adapted to transfer power from the second battery through the second converter to the first terminal of the first converter and from the second terminal of the first converter to the first battery in the third operating mode. The second converter is adapted to convert power from the second battery from a third voltage to the first voltage. The first converter is adapted to further convert power from the second battery from the first voltage at the first terminal to a second voltage at the second terminal.

[0020] According to this embodiment, the first battery is charged by the second battery in the third operating mode. A situation may arise where there is a large difference between the state of charge of the first battery and the state of charge of the second battery. The difference is, for example, larger than a threshold value. For example, the first battery is almost depleted, while the second battery is almost fully charged. In order for the first battery to be able to provide sufficient power, power is transferred from the second battery via the second converter and then via the first converter to the first battery. The second converter converts the power from the second battery from a third voltage to the first voltage, so that the first converter can further convert power from the first voltage to the second voltage. As a result, the first converter is used not only in the first and second operating modes, but also in the third operating mode. By making extensive use of the first converter, the power supply system requires only a minimum of electronic components.

[0021] In one embodiment, in the third mode of operation, the switching device is adapted to transfer power from both the second converter and the solar panel to the first terminal of the first converter.

[0022] According to this embodiment, the solar panel provides power in a third operating mode. In some circumstances, for example, during cloudy weather and / or when there is a high demand for power from the first battery, it may be desirable to charge the first battery with power from both the solar panel and the second battery simultaneously. The second converter converts power from the second battery from a third voltage to a first voltage and provides the power at the first voltage to a first terminal of the first converter. The solar panel provides the power at the first voltage to a first terminal of the first converter. Because both the solar panel and the second battery provide power at the first voltage to the first terminal of the first converter, the first converter can efficiently convert power from the first voltage at the first terminal to the second voltage at the second terminal. The power at the second voltage at the second terminal is further transferred to the first battery to charge the first battery.

[0023] In one embodiment, the second converter has a third terminal and a fourth terminal. In a second mode of operation, the third terminal is arranged to receive power from the first converter and the fourth terminal is arranged to transfer power to the second battery. The second converter is adapted to step up a first voltage at the third terminal to a third voltage at the fourth terminal. In a third mode of operation, the fourth terminal is arranged to receive power from the second battery and the third terminal is arranged to transfer power to the first converter and the second converter is adapted to step down the third voltage at the fourth terminal to the first voltage at the third terminal.

[0024] According to this embodiment, the second converter is adapted to transfer power from the third terminal to the fourth terminal in the second operating mode. The second converter increases the voltage of the power from a first voltage at the third terminal to a third voltage at the fourth terminal. The second converter is, for example, a boost converter. In the third operating mode, the second converter transfers power from the fourth terminal to the third terminal. In the third operating mode, by transferring power in the opposite direction to the second operating mode, the second converter can reduce the voltage of the power from the third voltage at the fourth terminal to the first voltage at the third terminal.

[0025] In one embodiment, in the second mode of operation, the switching device is adapted to transfer power from both the first terminal of the first converter and the solar panel to the second converter.

[0026] According to this embodiment, the second converter receives power from both the solar panel and the first battery simultaneously. This can be beneficial in a situation where the first battery is fully charged while the second battery is not fully charged. By supplying electrical energy from both the solar panel and the first battery to the second battery via the second converter, the second battery can be rapidly charged. The second converter can efficiently convert the power from the solar panel and the power from the first battery to the third voltage because both the power from the solar panel and the power from the first battery are supplied to the third terminal of the second converter at the first voltage. Furthermore, the electrical energy from the solar panel is directly supplied to the second converter instead of being first supplied to the first battery and then to the second converter, thereby reducing energy loss.

[0027] In one embodiment, the second voltage is a high voltage that is higher than the first voltage, and the third voltage is a low voltage that is lower than the first voltage.

[0028] In one embodiment, the second voltage is a low voltage that is lower than the first voltage, and the third voltage is a high voltage that is higher than the first voltage.

[0029] According to this embodiment, the first battery is a low-voltage battery that operates at a low voltage. The low voltage is lower than the voltage at which the solar panel supplies power. The second battery is a high-voltage battery that operates at a high voltage. The high voltage is higher than the voltage at which the solar panel supplies power. The first battery, for example, supplies power to an electrical system that operates at a low voltage. The second battery, for example, supplies power to an electrical system that operates at a high voltage. By supplying power from the solar panel at a first voltage that is between the second voltage and the third voltage, the power from the solar panel can be converted to either the second voltage or the third voltage without significant energy loss. The amount of energy loss is usually related to the difference between the voltage before conversion and the voltage after conversion. For example, converting an input voltage to an output voltage that is ten times the input voltage will result in more energy loss than converting the input voltage to an output voltage that is twice the input voltage. By supplying power from the solar panel at a first voltage that is between the second voltage and the third voltage, the difference between the first voltage and the second voltage and the difference between the first voltage and the third voltage will be minimized. As a result, energy losses in converting power from the solar panel to either the second voltage or the third voltage are limited.

[0030] In one embodiment, the first voltage is 4 to 8 times the low voltage, and the high voltage is 4 to 8 times the first voltage.

[0031] According to this embodiment, the first voltage of the solar panel is 4 to 8 times greater than the second voltage of the first battery. The third voltage of the second battery is 4 to 8 times greater than the first voltage of the solar panel. Thus, the third voltage is 16 to 64 times greater than the second voltage. By providing such differences between the first voltage, the second voltage, and the third voltage, it is possible to obtain a large difference between the second voltage and the third voltage, while converting them without excessive energy loss. A cheap and efficient converter can perform a 4 to 8 times step-down or step-up. Such a converter can, for example, step down an input voltage to an output voltage that is 4 to 8 times smaller than the input voltage. Such a converter can, for example, step up an input voltage to an output voltage that is 4 to 8 times larger than the input voltage.

[0032] For example, the first converter and / or the second converter are boost converters including an inductor. By selecting an inductor having a suitable inductance and setting a duty cycle of the boost converter, the boost converter is adapted to output a voltage that differs from an input voltage by 4 to 8 times. In another example, the first converter and / or the second converter are buck converters including an inductor. By selecting an inductor having a suitable inductance and setting a duty cycle of the buck converter, the buck converter is adapted to output a voltage that differs from an input voltage by 4 to 8 times.

[0033] In one embodiment, the low voltage is in the range of 11-15V, for example 12V. The high voltage is in the range of 300-430V, for example 360V. The first voltage is in the range of 50-60V, for example 55V.

[0034] According to this embodiment, the low voltage is suitable for use in applications requiring a voltage of about 12V. The high voltage of about 360V is suitable for applications requiring high power. By supplying a high voltage, it is possible to reduce the amount of current while supplying such a large power. By reducing the current, it is possible to reduce the energy loss when transferring power. By making the first voltage of the solar panel around 55V, the requirements for the electrical insulation of the solar panel are low. The requirements are low because a voltage of about 55V does not pose a high risk of electrocution. Due to the low requirements, for example, only thin insulating layers are used for the electrical components and wires of the solar panel. For example, even if the wires and components are closely arranged, there is no risk of discharge between the wires and the components. This increases the design freedom of the arrangement of the solar panel and the electrical connection with the solar panel.

[0035] When solar panels are mounted on vehicles, there is no need for additional safety measures to prevent electric shock in the event of a vehicle accident. Because solar panels are located on the outside of the vehicle, there is a risk that a person inside the vehicle or a rescuer may come into contact with the electrical components of the solar panel in the event of an accident. For example, a solar panel may break during an accident, exposing the conductive components of the solar panel. The conductive components may continue to carry current after an accident. A person exiting the vehicle may accidentally touch the conductive components. In another example, a rescuer may need to cut open the vehicle to get a person out of the vehicle. In that case, the rescuer may need to cut open a part of the vehicle that holds the conductive components, such as the wires that transfer current from the solar panel. Contact with the conductive components of the solar panel may be made directly or through a tool, such as a cutting tool. There is no risk of electrocution because the voltage of the solar panel is limited to approximately 55V. If a person comes into contact with the first voltage of approximately 55V, the contact will not result in injury.

[0036] Furthermore, by placing the second voltage in the range of 11-15V, the third voltage in the range of 300-430V, and the first voltage in the range of 50-60V, there is a difference of about 5 times between the first voltage and the second voltage, and a difference of about 6 times between the first voltage and the third voltage. The second voltage of about 12V is about 5 times smaller than the first voltage of about 55V. The third voltage of about 350V is about 6 times larger than the first voltage of about 55V. Operating the first converter to convert the first voltage to a second voltage that is 5 times larger and operating the second converter to convert the first voltage to a third voltage that is 6 times larger is an efficient way of operating the first converter and the second converter. The first converter and the second converter can perform these conversions with only limited energy losses.

[0037] In one embodiment, at least one of the first converter and the second converter is adapted to perform maximum power point tracking (MPPT).

[0038] According to an embodiment, the first converter and / or the second converter are further adapted to optimize the power provided by the solar panel by performing maximum power point tracking, also called MPPT. Either only the first converter or the second converter are adapted to perform MPPT or both the first converter and the second converter are adapted to perform MPPT. The amount of power generated by the solar panel depends on various conditions, such as whether it is sunny or cloudy, whether it is raining or not, what is the temperature, etc. Also, whether the solar panel is partially or completely shaded, etc. Depending on these conditions, the solar panel provides a constant voltage with a constant current. The power provided by the solar panel is the product of the voltage and the current. As much power as possible is desired. In order to obtain a large power from the solar panel, at least one of the first converter and the second converter is adapted to set the first voltage and / or control the current through the solar panel in order to maximize the power extracted from the solar panel. Preferably, the first converter and / or the second converter are adapted not to perform MPPT when no power is supplied from the solar panel, for example at night. When no power is supplied from the solar panel, performing MPPT limits the efficiency of the first converter or the second converter to convert the voltage of the current between the first battery and the second battery. At night, when no power is supplied from the solar panel, it is beneficial to use the first converter and the second converter to equalize the state of charge of the first battery and the second battery without performing MPPT.

[0039] In one embodiment, the power supply system includes a control system adapted to control the switching devices in a first mode of operation and a second mode of operation.

[0040] According to this embodiment, the control system is adapted to place the switching device in a position to connect the solar panel to the first battery via the first converter in the first operating mode. The control system is adapted to place the switching device in a position to connect the first battery to the second battery via the first converter and the second converter in the second operating mode. The control system has, for example, an input terminal for receiving an input. Based on the input, the control system controls the switching device to switch from the first operating mode to the second operating mode and vice versa. For example, the input comprises information about a state of charge of the first battery and / or the second battery. The input comprises, for example, information about an amount of power generated by the solar panel. The input comprises, for example, information about a demand for power from the first battery and / or the second battery. The information of the input is, for example, provided by a sensor. The sensor is, for example, a current sensor adapted to provide information about a current through the first battery and / or the second battery. The sensor is, for example, a voltage sensor adapted to provide information about a voltage across the first battery and / or the second battery. The sensor is for example a light sensor adapted to provide information about the amount of light incident on the solar panel. The sensor is for example a temperature sensor adapted to provide information about the temperature of the first battery, and / or the second battery, and / or the solar panel, and / or the ambient temperature.

[0041] In a second aspect of the invention, there is provided a vehicle including a power supply system as described above and an electrical system adapted to receive power from the power supply system.

[0042] According to a second aspect, a vehicle includes a solar panel for powering an electrical system of the vehicle. The electrical system receives power via a first battery, a second battery, or both the first battery and the second battery. As an example, the electrical system can receive power directly from the solar panel in addition to power from the first battery and / or the second battery.

[0043] In one embodiment, the vehicle includes a drive system for powering the vehicle. The drive system includes an electrical system.

[0044] According to an embodiment, the drive system is powered by a power supply system. The drive system includes, for example, an electric motor for propelling the vehicle. For example, the electric motor is an in-wheel motor arranged on a wheel of the vehicle. For example, the vehicle includes an in-wheel motor on every wheel. The in-wheel motor has a rotor rotatable relative to a stator. By supplying power to the in-wheel motor, the in-wheel motor generates a torque that rotates the rotor relative to the stator. By rotating the rotor, the vehicle is propelled. In another example, the drive system includes an electric motor, a gearbox, and a driveshaft. The electric motor is powered by the power supply system. The electric motor drives the driveshaft via the gearbox. The driveshaft is, for example, coupled to one or more wheels of the vehicle and propels the vehicle.

[0045] In one embodiment, the vehicle includes an auxiliary system, one of the first battery and the second battery powering the auxiliary system, and the other of the first battery and the second battery powering the electrical system.

[0046] According to this embodiment, the vehicle has a drive system and an auxiliary system. The auxiliary system may be any system other than the drive system. The auxiliary system includes, for example, a lighting system of the vehicle adapted to operate the lights of the vehicle. The auxiliary system includes, for example, a climate control system of the vehicle adapted to control the temperature of a cabin of the vehicle. The cabin provides a space for accommodating a person in or on the vehicle. As an example, the auxiliary system supports the drive system. For example, the auxiliary system includes a control system that controls the drive system or a part thereof. In another example, the auxiliary system includes a temperature control system adapted to control the temperature of the first battery and / or the second battery. The temperature control system is, for example, adapted to heat the first battery and / or the second battery when the temperature of the first battery and / or the second battery is lower than a threshold value.

[0047] In a third aspect of the present invention, a power conversion system is provided, including a first converter, a second converter, and a switching device. The first converter has a first terminal and a second terminal. The second converter has a third terminal and a fourth terminal. The switching device has a first switch terminal, a second switch terminal, and a third switch terminal. The switching device is adapted to transfer power in a first operation mode and a second operation mode. In the first operation mode, the switching device is adapted to transfer power from the first switch terminal to a first terminal of the first converter and from the second terminal of the first converter to a second switch terminal. The first converter is adapted to convert power from a first voltage at the first terminal to a second voltage at the second terminal. In a second mode of operation, the switching device is adapted to transfer power from the second switch terminal to the second terminal of the first converter, from the first terminal of the first converter to the third terminal of the second converter, and from the fourth terminal of the second converter to the third switch terminal. The first converter is adapted to convert power from the second switch terminal from a second voltage at the second terminal to a first voltage at the first terminal. The second converter is adapted to convert power from the first terminal from a first voltage at the third terminal to a third voltage at the fourth terminal.

[0048] In one embodiment, the first converter is adapted to step down a first voltage at the first terminal to a second voltage at the second terminal in a first operating mode, and to step up the second voltage at the second terminal to the first voltage at the first terminal in a second operating mode.

[0049] In one embodiment, the first switch terminal is adapted to be connected to a solar panel, the second switch terminal is adapted to be connected to a first battery, and the third switch terminal is adapted to be connected to a second battery.

[0050] In a fourth aspect of the present invention, there is provided a method of supplying electrical power, the method comprising: Step 1: supplying power at a first voltage to a first battery using a solar panel while converting power from the solar panel from the first voltage to a second voltage; Step 2: supplying power from the first battery to the second battery, while converting the power from the first battery from a second voltage to a first voltage, and further converting the power from the first battery from the first voltage to a third voltage; Step 3: supplying power from the second battery to the first battery, while converting the power from the second battery from a third voltage to the first voltage, and further converting the power from the second battery from the first voltage to a second voltage.

[0051] In one embodiment, the method comprises: Step 4: While performing step 3, converting power from the solar panel from a first voltage to a second voltage while supplying power from the solar panel to the first battery.

[0052] The invention will now be explained in more detail with reference to the figures, in which exemplary embodiments of the invention are shown in a non-limiting manner. [Brief description of the drawings]

[0053] [Figure 1] FIG. 2 illustrates an embodiment of the present invention in a first mode of operation in which a solar panel charges a first battery. [Diagram 2] FIG. 2 illustrates an embodiment of the present invention in a second mode of operation in which a first battery charges a second battery. [Diagram 3] FIG. 13 illustrates an embodiment of the present invention in a third mode of operation in which a second battery charges a first battery. [Figure 4] FIG. 2 illustrates a second embodiment of the present invention in a third mode of operation in which a second battery charges a first battery. [Diagram 5]FIG. 13 illustrates a third embodiment of the present invention in a fourth mode of operation in which the solar panel charges a second battery. [Figure 6] FIG. 13 illustrates a fourth embodiment of the present invention in a fourth mode of operation in which a solar panel and a first battery charges a second battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] FIG 1 illustrates an embodiment of the present invention in a first operating mode. FIG 1 illustrates a power supply system 100 including a solar panel 110, a first battery 111, a second battery 112, a first converter 121, a second converter 122, and a switching device 140. The solar panel 110 is adapted to generate power at a first voltage V1. The first battery 111 is for storing power at a second voltage V2. The second battery 112 is for storing power at a third voltage V3. The first converter 121 has a first terminal 131 and a second terminal 132. The switching device 140 is adapted to transfer power from the solar panel 110 to the first terminal 131 of the first converter 121 and from the second terminal 132 of the first converter 121 to the first battery 111 while in the first operating mode. The first converter 121 is adapted to convert power from the solar panel 110 from a first voltage V 1 at a first terminal 131 to a second voltage V 2 at a second terminal 132 .

[0055] 1 indicate the positive electrodes of the solar panel 110, the first battery 111, and the second battery 112. The "-" signs in FIG. 1 indicate the negative electrodes of the solar panel 110, the first battery 111, and the second battery 112.

[0056] The first terminal 131 includes a connection to a positive electrode and a connection to a negative electrode. The second terminal 132 includes a connection to a positive electrode and a connection to a negative electrode.

[0057] The solar panel 110, the first battery 111, the second battery 112, the first converter 121, and the second converter 122 are connected to each other via electrical connections such as wires. In the figure, the electrical connections are represented by solid and dashed lines. The solid lines between the solar panel 110, the first battery 111, and the second battery 112 indicate that the switching device 140 is configured to allow current through the electrical connections represented by the solid lines. The dashed lines between the solar panel 110, the first battery 111, and the second battery 112 indicate that the switching device 140 is configured to block current through the electrical connections represented by the dashed lines.

[0058] The first converter 121, the second converter 122 and the switching device 140 together form at least a part of the power conversion system 102. The switching device 140 has a first switch terminal 151, a second switch terminal 152 and a third switch terminal 153. The first switch terminal 151, the second switch terminal 152 and the third switch terminal 153 are each depicted in FIG. 1 as two terminals, one for a positive connection and one for a negative connection. The first switch terminal 151 is connected to the solar panel 110. The second switch terminal 152 is connected to the first battery 111. The third switch terminal 153 is connected to the second battery 112.

[0059] In a first operating mode, the switching device 140 is adapted to transfer power from the first switch terminal 151 to the first terminal 131 of the first converter 121 and from the second terminal 132 of the first converter 121 to the second switch terminal 152. The first converter 121 is adapted to convert power from a first voltage V1 at the first terminal 131 to a second voltage V2 at the second terminal 132. The first terminal 131 of the first converter 121 is connectable to the solar panel 110. The second terminal 132 of the first converter 121 is connectable to the first battery 111. The second converter 122 is connectable to the second battery 112 via the fourth terminal 134 of the second converter 122. The first switch terminal 151 is adapted to be connected to the solar panel 110. The second switch terminal 152 is adapted to be connected to the first battery 111. The third switch terminal 153 is adapted to be connected to the second battery 112 .

[0060] At least one of the first converter 121 and the second converter 122 is adapted to perform maximum power point tracking (MPPT).

[0061] The power supply system 100 includes a control system 160 .

[0062] The switching device 140 includes switches 141, 142, 143, and 144. The switch 141 is arranged to connect the terminal S1 to the positive pole of the first terminal 131 in one switch position and to connect the terminal S2 to the positive pole of the first terminal 131 in another switch position. The switch 142 is arranged to connect the terminal S3 to the negative pole of the first terminal 131 in one switch position and to connect the terminal S4 to the negative pole of the first terminal 131 in another switch position. The switch 143 is arranged to connect the terminal S5 to the positive pole of the third terminal 133 in one switch position and to connect the terminal S6 to the positive pole of the third terminal 133 in another switch position. The switch 144 is arranged to connect the terminal S7 to the negative pole of the third terminal 133 in one switch position and to connect the terminal S8 to the negative pole of the third terminal 133 in another switch position.

[0063] The terminal S1 is connected to the terminal S5. The terminal S2 is connected to the terminal S6 and the positive pole of the first switch terminal 151. The terminal S3 is connected to the terminal S7. The terminal S4 is connected to the negative pole of the first switch terminal 151 and the terminal S8.

[0064] In the first operation mode, the switch 141 is connected to the terminal S2 and connects the positive electrode of the solar panel 110 to the first terminal 131 of the first converter 121. The switch 142 is connected to the terminal S4 and connects the negative electrode of the solar panel 110 to the first terminal 131 of the first converter 121. With the switch 141 connected to the terminal S2 and the switch 142 connected to the terminal S4, a current flows between the solar panel 110 and the first battery 111. With this current, power is transferred from the solar panel 110 to the first battery 111, and the first battery 111 is charged.

[0065] 2 shows the embodiment of FIG. 1 in a second operating mode in which the first battery 111 charges the second battery 112. In the second operating mode, the switching device 140 is adapted to transfer power from the first battery 111 to the second terminal 132 of the first converter 121, and from the first terminal 131 of the first converter 121 to the second converter 122, and from the second converter 122 to the second battery 112. The first converter 121 is adapted to convert power from the first battery 111 from a second voltage V2 at the second terminal 132 to a first voltage V1 at the first terminal 131. The second converter 122 is adapted to convert power from the first battery 111 from the first voltage V1 to a third voltage V3.

[0066] In a second operating mode, the switching device 140 is adapted to transfer power from the second switch terminal 152 to the second terminal 132 of the first converter 121, and from the first terminal 131 of the first converter 121 to the second converter 122, and from the second converter 122 to the third switch terminal 153. The first converter 121 is adapted to convert power from the second switch terminal 152 from a second voltage V2 at the second terminal 132 to a first voltage V1 at the first terminal 131. The second converter 122 is adapted to convert power from the third terminal 133 from the first voltage V1 to a third voltage V3 at the fourth terminal 134.

[0067] In the second operation mode, the switch 141 is connected to the terminal S1 and connects the positive pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 142 is connected to the terminal S3 and connects the negative pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 143 is connected to the terminal S5 and connects the positive pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 144 is connected to the terminal S7 and connects the negative pole of the first battery 111 to the third terminal 133 of the second converter 122. The switches 141 and 143 are connected to the terminals S1 and S5, respectively, and the switches 142 and 144 are connected to the terminals S3 and S7, respectively, so that a current flows between the first battery 111 and the second battery 112. This current transfers power from the first battery 111 to the second battery 112, causing the second battery 112 to be charged.

[0068] The control system 160 is adapted to control the switching device 140 to connect the switches 141-144 to the terminals S1, S3, S5, and S7, respectively. The control system 160 may further be adapted to control a direction of a current from the first battery 111 to the second battery 112 to charge the second battery 112 with power from the first battery 111.

[0069] The first converter 121 is adapted to step down a first voltage V1 at the first terminal 131 to a second voltage V2 at the second terminal 132 in a first operating mode. The first converter 121 is adapted to step up the second voltage V2 at the second terminal 132 to the first voltage V1 at the first terminal 131 in a second operating mode. The second voltage V2 is a low voltage lower than the first voltage V1. The third voltage V3 is a high voltage higher than the first voltage V1.

[0070] In this embodiment, the first voltage V1 is 4 to 8 times the second voltage V2. The third voltage V3 is 4 to 8 times the first voltage V1. The second voltage V2 is in the range of 11 to 15 V, for example, 12 V. The third voltage V3 is in the range of 300 to 430 V, for example, 360 V. The first voltage V1 is in the range of 50 to 60 V, for example, 55 V.

[0071] In an alternative embodiment, the second voltage V2 is a high voltage higher than the first voltage V1. The third voltage V3 is a low voltage lower than the first voltage V1. In an alternative embodiment, the first voltage V1 is 4 to 8 times smaller than the second voltage V2. The third voltage V3 is 4 to 8 times smaller than the first voltage V1. The third voltage V3 is in the range of 11 to 15 V, for example 12 V. The second voltage V2 is in the range of 300 to 430 V, for example 360 ​​V. The first voltage V1 is in the range of 50 to 60 V, for example 55 V.

[0072] The control system 160 is adapted to control the switching device 140 in a first operation mode and a second operation mode. The control system 160 is connected to the switching device 140 and transmits a control signal to the switching device 140. Under the control of the control signal, the switching device 140 changes the position of the switches 141-144 to put the power supply system 100 in the first operation mode or the second operation mode. The control system 160 is adapted to control the first converter 121 and the second converter 122 to control the direction of the current through the first converter 121 and the second converter 122, respectively. For example, the control system 160 is adapted to control the direction of the current by load-source reversal or phase shift reversal. The control system 160 is adapted to receive information signals from the power supply system 100 regarding the state of the power supply system 100. The information signal includes, for example, information about the power supplied by the solar panel 110, the temperature of the first battery 111 and / or the second battery 112, the state of charge of the first battery 111 and / or the second battery 112, the current value of the second voltage V2 and / or the current value of the third voltage V3.

[0073] 3 illustrates an embodiment of the present invention in a third operation mode in which the second battery 112 charges the first battery 111. The switching device 140 is adapted to transfer power from the second battery 112 to the first terminal 131 of the first converter 121 via the second converter 122 and to transfer power from the second terminal 132 of the first converter 121 to the first battery 111 in the third operation mode. The second converter 122 is adapted to convert power from the second battery 112 from a third voltage V3 at the fourth terminal 134 to a first voltage V1 at the third terminal 133. The first converter 121 is adapted to convert power from the second battery 112 from the first voltage V1 at the first terminal 131 to a second voltage V2 at the second terminal 132.

[0074] In the third operation mode, the switch 141 is connected to the terminal S1 and connects the positive pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 142 is connected to the terminal S3 and connects the negative pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 143 is connected to the terminal S5 and connects the positive pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 144 is connected to the terminal S7 and connects the negative pole of the first battery 111 to the third terminal 133 of the second converter 122. The switches 141 and 143 are connected to the terminals S1 and S5, respectively, and the switches 142 and 144 are connected to the terminals S3 and S7, respectively, so that a current flows between the first battery 111 and the second battery 112. This current transfers power from the second battery 112 to the first battery 111, causing the first battery 111 to be charged.

[0075] The control system 160 is adapted to control the switching device 140 to connect the switches 141-144 to the terminals S1, S3, S5 and S7, respectively. The control system 160 may further be adapted to control a direction of current from the second battery 112 to the first battery 111 to charge the first battery 111 with power from the second battery 112.

[0076] Figure 4 shows a second embodiment of the present invention. The second embodiment is the same as the embodiment depicted in Figures 1 to 3, except for the following: The second embodiment of Figure 4 is in a third mode of operation. In the third mode of operation, the switching device 140 is adapted to transfer power from both the second converter 122 and the solar panel 110 to the first terminal 131 of the first converter 121.

[0077] In the third operation mode, the switch 141 is connected to the terminal S2 and connects the positive electrode of the solar panel 110 to the first terminal 131 of the first converter 121. The switch 142 is connected to the terminal S4 and connects the negative electrode of the solar panel 110 to the first terminal 131 of the first converter 121. The switch 143 is connected to the terminal S6 and connects the positive electrode of the second battery 112 to the first terminal 131 of the first converter 121. The switch 144 is connected to the terminal S8 and connects the negative electrode of the second battery 112 to the first terminal 131 of the first converter 121. By connecting the switches 141 and 143 to the terminals S2 and S6, respectively, and connecting the switches 142 and 144 to the terminals S4 and S8, respectively, two currents are allowed to flow. One current flows between the solar panel 110 and the first battery 111. The other current flows between the second battery 112 and the first battery 111. As a result, the current transfers power from both the solar panel 110 and the second battery 112 to the first battery 111, charging the first battery 111.

[0078] The control system 160 is adapted to control the switching device 140 to connect the switches 141-144 to the terminals S2, S4, S6 and S8, respectively. The control system 160 may further be adapted to control a direction of current from the second battery 112 to the first battery 111 to charge the first battery 111 with power from the second battery 112.

[0079] 5 illustrates a third embodiment of the present invention in a fourth operation mode in which the solar panel 110 charges the second battery 112. The third embodiment is similar to the first or second embodiment described above, except for the following points.

[0080] In the fourth mode of operation, the switching device 140 is adapted to transfer power from the solar panel 110 to the second battery 112. In the fourth mode of operation, no power is transferred from the solar panel 110 to the first battery 111.

[0081] In the fourth operation mode, the switch 141 is connected to the terminal S1 to disconnect the first converter 121 from the solar panel 110. The switch 142 is connected to the terminal S3 to disconnect the first converter 121 from the solar panel 110. The switch 143 is connected to the terminal S6 to connect the positive electrode of the solar panel 110 to the third terminal 133 of the second converter 122. The switch 144 is connected to the terminal S8 to connect the negative electrode of the solar panel 110 to the third terminal 133 of the second converter 122. With the switches 141 and 142 connected to the terminals S1 and S3, respectively, and the switches 143 and 144 connected to the terminals S6 and S8, respectively, a current flows between the solar panel 110 and the second battery 112, but no current flows between the solar panel 110 and the first battery 111. As a result, current transfers power from the solar panel 110 to the second battery 112, which is charged. No power is transferred to the first battery 111.

[0082] The control system 160 is adapted to control the switching device 140 to connect the switches 141-144 to the terminals S1, S3, S6, and S8, respectively.

[0083] 6 illustrates a fourth embodiment of the present invention in a fourth operation mode in which the solar panel 110 and the first battery 111 charge the second battery 112. The fourth embodiment is the same as the third embodiment depicted in FIG. 5, except as follows. The fourth embodiment of FIG. 6 is in a fourth operation mode. In the fourth operation mode, the switching device 140 is adapted to transfer power from the solar panel 110 and the first battery 111 to the second battery 112.

[0084] In the fourth operating mode, the switch 141 is connected to the terminal S2 and connects the positive pole of the first battery 111 to the third terminal 133 of the second converter 122. The switch 142 is connected to the terminal S4 and connects the negative pole of the first battery 111 to the third terminal 133 of the second converter 122. As already shown in FIG. 5, the switch 143 is connected to the terminal S6 and connects the positive pole of the solar panel 110 to the third terminal 133 of the second converter 122. The switch 144 is connected to the terminal S8 and connects the negative pole of the solar panel 110 to the third terminal 133 of the second converter 122. By connecting the switches 141 and 143 to the terminals S2 and S6, respectively, and connecting the switches 142 and 144 to the terminals S4 and S8, respectively, two currents are allowed to flow. One current flows between the solar panel 110 and the second battery 112. The other current flows between the first battery 111 and the second battery 112. As a result, the current transfers power from both the solar panel 110 and the first battery 111 to the second battery 112, charging the second battery 112.

[0085] The control system 160 is adapted to control the switching device 140 to connect the switches 141-144 to the terminals S2, S4, S6 and S8, respectively. The control system 160 may further be adapted to control a direction of current from the first battery 111 to the second battery 112 to charge the second battery 112 with power from the first battery 111.

[0086] In one embodiment of the present invention, the power supply system 100 has a switching device 140 adapted to connect the solar panel 110, the first battery 111 and the second battery 112 according to the first operating mode, the second operating mode, the third operating mode and the fourth operating mode, as described above.

[0087] Where necessary, detailed embodiments of the present invention will be described herein. However, it should be understood that the disclosed embodiments serve only as examples, and the present invention may be embodied in other forms. Therefore, the specific structural aspects disclosed herein should not be considered as limiting the present invention, but merely as a basis for the claims and for enabling the present invention to be implemented by an average person skilled in the art.

[0088] Moreover, various terms used herein should not be construed as limiting, but rather as a comprehensive description of the present invention.

[0089] As used herein, the term "a" means one or more, unless otherwise specified. The term "a plurality of" means two or more. The words "comprising" and "having" do not exclude the presence of more elements.

[0090] Reference numerals in the claims should not be construed as limiting the invention. It is not necessary for a particular embodiment to achieve all of the objectives described.

[0091] The mere fact that certain technical measures are defined in different dependent claims still allows that a combination of these technical measures can be applied to advantage. [Explanation of symbols]

[0092] 100 Power Supply System 102 Power Conversion Systems 110 Solar Panel 111 First Battery 112 Second Battery 121 First Converter 122 Second Converter 131 First Terminal 132 Second Terminal 133 Third Terminal 134 Fourth Terminal 121 First Converter 122 Second Converter 140 Switching Device 141, 142, 143, 144 Switches 151 First switch terminal 152 Second switch terminal 153 Third Switch Terminal 160 Control System S1, S2, S3, S4, S5, S6, S7, S8 terminals V1 First voltage V2 Second voltage V3 Third voltage

Claims

1. A power supply system (100), comprising: a solar panel (110) for generating power at a first voltage (V1); a first battery (111) for storing power at a second voltage (V2); a second battery (112) for storing power at a third voltage (V3); a first converter (121) having a first terminal (131) and a second terminal (132); A second converter (122); A switching device (140); Including, the switching device (140) is adapted to transfer power in a first mode of operation and a second mode of operation; In the first mode of operation: the switching device (140) is adapted to transfer power from the solar panel (110) to the first terminal of the first converter (121) and from the second terminal of the first converter (121) to the first battery (111); the first converter (121) is adapted to convert the power from the solar panel (110) from the first voltage (V1) at the first terminal to the second voltage (V2) at the second terminal; In the second mode of operation, the switching device (140) is adapted to transfer power from the first battery (111) to the second terminal of the first converter (121), from the first terminal of the first converter (121) to the second converter (122), and from the second converter (122) to the second battery (112); the first converter (121) is adapted to convert the power from the first battery (111) from the second voltage (V2) at the second terminals to the first voltage (V1) at the first terminals; the second converter (122) is adapted to convert the power from the first battery (111) from the first voltage (V1) to the third voltage (V3); A power supply system (100).

2. the first converter (121) is adapted to step down the first voltage (V1) at the first terminal (131) to the second voltage (V2) at the second terminal (132) in the first operating mode, and to step up the second voltage (V2) at the second terminal (132) to the first voltage (V1) at the first terminal (131) in the second operating mode; The power supply system (100) of claim 1.

3. the switching device (140) is adapted to transfer power from the second battery (112) via the second converter (122) to the first terminal (131) of the first converter (121) and from the second terminal (132) of the first converter (121) to the first battery (111) in a third operating mode; the second converter (122) is adapted to convert the power from the second battery (112) from the third voltage (V3) to the first voltage (V1); the first converter (121) is adapted to convert the power from the second battery (112) from the first voltage (V1) at the first terminal (131) to the second voltage (V2) at the second terminal (132); The power supply system (100) of claim 1.

4. In the third operating mode, the switching device (140) is adapted to transfer power from both the second converter (122) and the solar panel (110) to the first terminal (131) of the first converter (121). The power supply system (100) of claim 3.

5. the second converter (122) has a third terminal (133) and a fourth terminal (134), and in the second operating mode, the third terminal (133) is arranged to receive power from the first converter (121) and the fourth terminal (134) is arranged to transfer power to the second battery (112), and the second converter (122) is adapted to boost the first voltage (V1) at the third terminal (133) to the third voltage (V3) at the fourth terminal (134); In the third operating mode, the fourth terminal (134) is arranged to receive power from the second battery (112), the third terminal (133) is arranged to transfer the power to the first converter (121), and the second converter (122) is adapted to step down the third voltage (V3) at the fourth terminal (134) to the first voltage (V1) at the third terminal (133). The power supply system (100) of claim 3.

6. In the second operating mode, the switching device (140) is adapted to transfer power from both the first terminal (131) of the first converter (121) and the solar panel (110) to the second converter (122). The power supply system (100) of claim 1.

7. The second voltage (V2) is a high voltage higher than the first voltage (V1), and the third voltage (V3) is a low voltage lower than the first voltage (V1). The power supply system (100) of claim 1.

8. The second voltage (V2) is a low voltage lower than the first voltage (V1), and the third voltage (V3) is a high voltage higher than the first voltage (V1). The power supply system (100) of claim 1.

9. The first voltage (V1) is 4 to 8 times the low voltage, and the high voltage is 4 to 8 times the first voltage (V1); The power supply system (100) of claim 7.

10. the low voltage is in the range of 11 to 15 V, the high voltage is in the range of 300 to 430 V, and the first voltage (V1) is in the range of 50 to 60 V; The power supply system (100) of claim 7.

11. At least one of the first converter (121) and the second converter (122) is adapted to perform maximum power point tracking (MPPT); The power supply system (100) of claim 1.

12. a control system (160) adapted to control the switching device (140) in the first mode of operation and in the second mode of operation. The power supply system (100) of claim 1.

13. A power supply system (100) according to claim 1 and an electrical system adapted to receive power from said power supply system (100); Including, vehicles.

14. a drive system for driving the vehicle; The drive system includes the electrical system.

14. A vehicle as claimed in claim 13.

15. Including auxiliary systems, one of the first battery (111) and the second battery (112) supplies power to the auxiliary system, and the other of the first battery (111) and the second battery (112) supplies power to the electrical system.

15. A vehicle as claimed in claim 14.

16. A power conversion system (102) comprising a first converter (121), a second converter (122), and a switching device (140), The first converter (121) has a first terminal (131) and a second terminal (132); the second converter (122) has a third terminal (133) and a fourth terminal (134); The switching device (140) has a first switch terminal (151), a second switch terminal (152), and a third switch terminal (153); the switching device (140) is adapted to transfer power in a first mode of operation and a second mode of operation; In the first mode of operation: the switching device (140) is adapted to transfer power from the first switch terminal (151) to the first terminal (131) of the first converter (121) and to transfer power from the second terminal (132) of the first converter (121) to the second switch terminal (152); the first converter (121) is adapted to convert the power from a first voltage (V1) at the first terminal to a second voltage (V2) at the second terminal; In the second mode of operation, the switching device (140) is adapted to transfer power from the second switch terminal (152) to the second terminal of the first converter (121), from the first terminal of the first converter (121) to the third terminal of the second converter (122), and from the fourth terminal of the second converter (122) to the third switch terminal (153); the first converter (121) is adapted to convert the power from the second switch terminal (152) from the second voltage (V2) at the second terminal to the first voltage (V1) at the first terminal; the second converter (122) is adapted to convert the power from the first terminal from the first voltage (V1) at the third terminal to a third voltage (V3) at the fourth terminal (134); A power conversion system (102).

17. the first converter (121) is adapted to step down the first voltage (V1) at the first terminal (131) to the second voltage (V2) at the second terminal (132) in the first operating mode, and to step up the second voltage (V2) at the second terminal (132) to the first voltage (V1) at the first terminal (131) in the second operating mode; 17. The power conversion system (102) of claim 16.

18. the first switch terminal (151) is adapted to be connected to a solar panel (110), the second switch terminal (152) is adapted to be connected to a first battery (111), and the third switch terminal (153) is adapted to be connected to a second battery (112); 17. The power conversion system (102) of claim 16.

19. 1. A method of supplying electrical power, the method comprising: Step 1: supplying power at a first voltage (V1) to a first battery (111) using a solar panel (110) while converting the power from the solar panel (110) from the first voltage (V1) to a second voltage (V2); Step 2: supplying power from the first battery (111) to a second battery (112), while converting the power from the first battery (111) from the second voltage (V2) to the first voltage (V1), and further converting the power from the first battery (111) from the first voltage (V1) to a third voltage (V3); Step 3: supplying power from the second battery (112) to the first battery (111), while converting the power from the second battery (112) from the third voltage (V3) to the first voltage (V1), and further converting the power from the second battery (112) from the first voltage (V1) to the second voltage (V2); 23. A method for providing electrical power comprising:

20. Step 4: while performing step 3, supplying power from the solar panel (110) to the first battery (111), and converting the power from the solar panel (110) from the first voltage (V1) to the second voltage (V2); 20. The method of claim 19.

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