Electric vehicle with solar panel
By adopting the topological structure of differential power processing converters and string converters in electric vehicles, the low-voltage battery is directly charged and the high-voltage battery is charged through the string converter, which solves the problems of low charging efficiency and cost-effectiveness of the on-board solar panels, and achieves high efficiency , economical battery charging effect.
Patent Information
- Application Number
- CN202380038713.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-03
- Filing Date
- 2023-05-30
- Publication Date
- 2024-12-17
AI Technical Summary
In the prior art, the on-board solar panels are less efficient and cost-effective when charging electric vehicle batteries, and there are problems of additional losses.
Differential power processing converter and series converter topology using low-voltage and high-voltage batteries, series series of n solar panels and DC-DC converter, the differential power processing converter is directly charged with low-voltage batteries, and the series converter is charged with high-voltage batteries. , avoid energy transfer from high-voltage batteries to low-voltage batteries, and improve overall efficiency.
It realizes efficient and economical battery charging, reduces the size and cost of low-voltage batteries, reduces the demand for switches and other components, and improves charging efficiency and overall system stability.
Smart Images
Figure CN119156754A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an electric vehicle comprising a low voltage battery and a high voltage battery, a series string of solar panels and a DC-DC converter, wherein a load-side positive output terminal of the converter is connected to a positive electrode of one of the batteries and a load-side negative output terminal of the converter is connected to a negative electrode of the battery. Background Art
[0002] US2007 / 0125417A1 discloses a solar energy system for a hybrid vehicle, which utilizes an attachable solar panel to receive solar energy and convert it into direct current. A wiring harness guides the direct current generated by the solar panel to a converter. The converter converts the direct current from a relatively low energy state to a relatively high energy state.
[0003] US2013 / 0092457A1 discloses a photovoltaic device for a vehicle, which includes a plurality of solar modules electrically isolated from each other and adapted to receive solar radiation and convert the radiation into electrical energy. The device includes at least one DC / DC converter electrically coupled to the electrically isolated modules and adapted to receive electrical energy from the solar modules and increase the voltage for transmission to at least one component of the vehicle. The solar module includes a plurality of solar cells adapted to receive solar radiation and convert the radiation into electrical energy.
[0004] US8120308B2 discloses a connection system suitable for charging a high voltage battery in an electric vehicle with a plurality of low voltage solar panels. The connection system includes a plurality of transmission lines to individually connect each solar panel to each of the cells that make up the battery. Through the connection system, the high voltage battery can be charged by the lower voltage solar panel without using a lossy DC-DC converter system that converts the output of the DC solar panel to AC for conversion to a higher voltage at the primary terminals of the battery and then converted back to DC for connection to the battery.
[0005] US8633671B2 discloses a photovoltaic (PV) system for charging a high voltage battery used to power an electric traction motor of an electric vehicle. A suitable PV system made of interconnected solar cells, modules or arrays can be designed and adapted to efficiently charge the high voltage battery by matching the characteristics of the PV system to the full charge voltage of the battery. Preferably, by appropriately matching the PV system to the battery, a charging efficiency of about 90% or more can be achieved. A reconfigurable PV system based on an assembly of solar modules is also described. The reconfigurable PV system is capable of appropriately matching itself to a variety of different batteries, each of which may have a different voltage when fully charged. By using several reconfigurable PV systems, various batteries with different charging voltages can be charged simultaneously while essentially utilizing the full capacity of the PV system to charge the battery.
[0006] US9583939B2 discloses a solar power system for maximizing solar energy conversion. The solar power system includes n power units connected in series and n-1 DC-DC conversion units, and each of the n-1 DC-DC conversion units is coupled to at least one of the n solar power units. Each of the n-1 DC-DC conversion units is configured to control the operation of the corresponding connected solar power unit to generate a target current. The solar power system also includes a control unit coupled to the n-1 DC-DC conversion units. The control unit monitors and compares the n currents generated by the n solar power units. Based on the current comparison, the control unit determines the series current and controls the n solar power units so that each generated photovoltaic current is substantially equal to the determined series current.
[0007] US9614399B2 discloses a solar ECU included in a charging controller configured to temporarily store the power generated by the on-board solar cell of the power supply unit in a low-voltage battery when the vehicle is running. In addition, when the vehicle is running, the battery ECU included in the charging controller is configured to keep the charging relay in an open state (disconnected state) so that the power temporarily stored in the low-voltage battery is not supplied to the main battery. On the other hand, when the vehicle is running, the solar ECU supplies the power temporarily stored in the low-voltage battery to the sub-battery.
[0008] US9799779B2 discloses a system and method including a circuit for protecting a photovoltaic string. A bypass switch is connected in parallel to the photovoltaic string and a hot spot protection switch is connected in series with the photovoltaic string. A first control signal controls the opening and closing of the bypass switch, and a second control signal controls the opening and closing of the hot spot protection switch. When a hot spot condition is detected, the first control signal closes the bypass switch, and after the bypass switch is closed, the second control signal opens the hot spot protection switch.
[0009] US2022 / 0045628A1 discloses a disclosed power conversion circuit. The power conversion circuit includes at least one DC bus. The power conversion circuit also includes a plurality of DC-AC conversion units, which are coupled to the DC bus and configured to convert a DC voltage into an AC voltage. The power conversion circuit also includes a multi-winding transformer, which includes a magnetic core and a plurality of windings, wherein each DC-AC conversion unit is coupled to a corresponding winding of the multi-winding transformer.
[0010] The article “Review of DifferentialPowerProcessingConverterTechniquesforPhotovoltaicApplications” by Hoejeong Jeong, Hyunji Iee, Yu-Chen Iiu, and Katherine A. Kim in the IEEE Transactions on Energy Conversion, Volume 34, Issue 1, March 2019, Pages 351-360, reviews differential power processing (DPP) converters used in photovoltaic (PV) power systems to achieve efficient power output even in the presence of uneven illumination or mismatched PV cells. Since the introduction of this DPP concept in PV systems, various topologies and control algorithms have been proposed and verified, demonstrating the benefits of differential power processing converter systems over existing series string and full power processing converter solutions. However, DPP systems are highly coupled and can be difficult to control. Various architectures, topologies, and control strategies for series and parallel DPP architectures are reviewed and compared. The trade-offs of different differential power processing converters and topologies are discussed. Furthermore, the power curves of PV-to-bus, PV-to-PV, and PV-to-independent-port series DPP architectures are evaluated from the inverter interaction perspective.
[0011] In Figure 3 of the article by Hoejeong Jeong et al., a PV-to-bus direct connection architecture is shown that is able to reduce the amount of power that must be handled by the differential power handling converter (ideally 0 W when the solar cells are generating power under exactly the same conditions (such as aging, radiation, temperature, etc.). However, the disadvantage of this architecture is that it can only supply one grid (high voltage HV or low voltage LV), which means that if the energy is to be transmitted to a grid that is not directly connected to the solar panel, additional losses will be incurred. Summary of the invention
[0012] It is an object of the present invention to at least partially overcome the problems associated with the prior art.A particular object of the present invention is to provide a particularly efficient and cost-effective method of charging the battery of an electric car using an on-board solar panel.
[0013] This object is achieved according to the features of the independent claims. Advantageous embodiments can be found, for example, in the dependent claims and / or in the description.
[0014] The object is achieved in particular by an electric vehicle comprising a low voltage (LV) battery, a high voltage (HV) battery, a series string of n>1 solar panels, n first DC-DC differential power processing converters and a second DC-DC converter (hereinafter, for the sake of generality, also referred to as "string converters"). The supply-side positive input terminal of each differential power processing converter is connected to the positive output terminal of the corresponding solar panel. The supply-side negative input terminal is connected to the negative output terminal of the corresponding solar panel. The load-side positive output terminal of the differential power processing converter is connected to the positive pole of the low voltage battery. The load-side negative output terminal of the differential power processing converter is connected to the negative pole of the low voltage battery. The supply-side positive input terminal of the string converter is connected to the positive output terminal of the series string of solar panels. The supply-side negative input terminal is connected to a reference potential. The load-side positive output terminal of the string converter is connected to the positive pole of the high voltage battery. The negative pole of the high voltage battery can be connected to the reference potential. The load-side negative output terminal of the string converter is connected to the reference potential. The controller or control device is suitable for controlling the operation of the string converter and the differential power processing converter.
[0015] The advantage of such an electric vehicle is that since the charging energy does not need to be transferred from the high voltage battery to the low voltage battery, an overall efficiency gain is achieved by directly feeding the low voltage battery through the output of the differential power handling converter.
[0016] Furthermore, the low voltage battery operates at a stable constant voltage and, since the control strategy tends to minimize the energy handled, the low voltage battery will only exchange only a small amount of energy with the differential power handling converter, so the typical low capacity low voltage battery is very suitable. In addition, the low voltage battery can be reduced in size because it will be charged by the solar energy of the solar panel when the solar cell generates electricity under different conditions such as manufacturing tolerances, different aging, different solar radiation, temperature, etc. This in turn reduces the cost. In addition, no other components such as switches are required.
[0017] The electric vehicle may be a plug-in hybrid electric vehicle (PHEV) or a full battery electric vehicle (BEV). The electric vehicle may be a passenger car, a truck, a bus, a motorcycle, etc.
[0018] In particular, "positive" and "negative" refer to electrical polarity or voltage levels.
[0019] In particular, the high voltage battery is an electric vehicle battery EVB. The high voltage battery HV may be, for example, a lithium-ion battery.
[0020] A low voltage battery may be provided for powering low voltage electrical loads, such as ECUs and sensors. The low voltage battery LV may be, for example, a lead acid battery.
[0021] Alternatively, the low voltage battery can be part of the high voltage battery. This can be achieved in such a way that some cells of the high voltage battery are used to provide voltage / power for the LV grid.
[0022] A solar / photovoltaic panel may include one or more solar cells and may also be referred to as a solar module or photovoltaic (PV) module. Incident light causes the solar panel to generate a voltage that exists between associated output terminals, namely a positive output terminal (terminal) and a negative output terminal (terminal).
[0023] Arranging n>1 (i.e., two or more) solar panels in a series string includes electrically connecting the solar panels in series such that a negative output terminal of the solar panel is connected to a positive output terminal of the next solar panel in the series string. The positive output terminal of the first solar panel that is not connected to another solar panel and the negative output terminal of the nth and last solar panel that is also not connected to another solar panel can be regarded as the positive output terminal and the negative output terminal of the series string, respectively.
[0024] In particular, the differential power handling converter converts the DC voltage generated by the solar panel connected to its supply side into a DC voltage on its load side. The load side voltage is then applied to the low voltage battery. The differential power handling converter operates under the control of the controller. In particular, the differential power handling converter includes at least one electronic switch, such as a transistor, such as a MOSFET. The operation of the at least one electronic switch can be operated by the controller to achieve the desired conversion characteristics. For example, in nominal operation, the differential power handling converter can operate in a "DPP mode" in which the amount of energy flowing through the differential power handling converter is minimized to prevent losses.
[0025] Connecting the load-side positive output of the differential power processing converter to the positive electrode of the low-voltage battery particularly includes connecting the positive outputs of all n differential power processing converters to each other and to the positive electrode of the low-voltage battery.
[0026] In particular, the string converter boosts the positive voltage applied to the positive input terminal of the supply side thereof through the positive output terminal of the series string of the solar panel (while reducing the current), and applies the boosted voltage to the positive electrode of the high voltage battery. Thus, the high voltage battery is charged through the string converter. The string converter may include at least one electronic switch, such as a transistor, such as a MOSFET. The operation of the at least one electronic switch may also be operated by a controller to achieve the desired conversion characteristics. The controller that controls the operation of the string converter may be the same controller that controls the operation of the differential power processing converter, or may be a different controller.
[0027] Therefore, the above topology can include four reference potentials:
[0028] - a "first" reference potential connected to the negative input of the string converter;
[0029] - a "second" reference potential connected to the negative output of the string converter;
[0030] - a "third" reference potential connected to the negative terminal of the high voltage battery; and
[0031] - A "fourth" reference potential connected to the negative terminal of the low voltage battery.
[0032] These reference potentials may be all different, partially different, or all the same. For example, the reference potentials connected to the negative input terminal of the string converter and the negative output terminal of the string converter, respectively, may be the same as or different from the reference potential connected to the negative electrode of the high-voltage battery. For example, the reference potential connected to the negative electrode of the high-voltage battery may be different from the reference potential connected to the negative electrode of the low-voltage battery.
[0033] The controller may include one or more IC components or units, such as a microcontroller, FPGA, ASIC, etc. The controller may be adapted (e.g. programmed) to operate the differential power handling converter in a "DPP mode", in which the amount of energy flowing through the differential power handling converter is minimized to keep losses small. In the DPP mode, the low voltage battery is only charged by the differential power handling converter if there is an imbalance, i.e. if the voltage levels applied to the differential power handling converter by the solar panels are different (e.g. due to manufacturing tolerances, different solar incidence intensities, etc.). The DPP mode of operation is generally known, for example as described in the above-mentioned article by Hoejeong Jeong et al., and is therefore not described further.
[0034] Connecting the output terminals of the converter to respective poles of respective batteries may comprise a direct connection or an indirect connection via a low voltage or high voltage power supply system of the vehicle.
[0035] This arrangement of solar panels and converters may also be referred to as a PV-bus direct connection architecture with a differential power handling converter. The converter may be implemented and / or operated with an architecture similar to that described in FIG. 3 of the article by Hoejeong Jeong et al. However, the difference from FIG. 3 of the article by Hoejeong Jeong et al. is that in the present case, the positive pole of the high-voltage battery is only connected to the string converter and thus the high-voltage battery is only charged by the string converter, while at the same time the positive pole of the low-voltage battery is only connected to the differential power handling converter and thus the low-voltage battery is only charged by the differential power handling converter. This gives the above-mentioned advantages of the present invention.
[0036] In one embodiment, the electric vehicle further comprises a battery charger connected to the high voltage battery. This enables the high voltage battery to be charged at a charging point by the battery charger. The charging station may be, for example, a charging station or a wall box.
[0037] In one embodiment, the battery charger is an AC charger, i.e., a charger that converts the AC supply current from the charging station into a DC current applied to the high-voltage battery. An advantage of this embodiment is that it can be widely implemented, since many electric vehicles to date use an on-board AC charger. Such an AC charger usually also has a DC-DC converter function to convert the rectified AC supply voltage to the voltage level of the high-voltage battery. The AC charger can also be a charger for converting the AC induction voltage generated by wireless induction charging.
[0038] In one embodiment, the battery charger is a DC charger, ie a charger that converts a DC supply voltage from a charging station into a DC voltage that is applied to the high voltage battery. This embodiment is particularly useful for electric vehicles adapted for DC fast charging.
[0039] In one embodiment, the string converter is a battery charger. This has the advantage that no additional components need to be provided as string converters, which in turn reduces costs. The battery charger therefore also acts as a DC-DC converter between the string converter and the positive electrode of the high voltage battery. In one embodiment, the charger may be adapted to switch back and forth between converting the voltage from an external charging source to a high voltage battery voltage (e.g., from 110V or 230V to 400V) and converting the voltage from the solar panel string to a high voltage battery voltage as required.
[0040] In one embodiment, the string converter is a boost converter. This is particularly advantageous for increasing the voltage level of the solar panel string to the voltage level required for charging the high voltage battery. In particular, the voltage / current conversion is usually regulated by PWM (pulse width modulation). Therefore, by adjusting the PWM characteristics, switching between converting the voltage / current from the external charging source to the high voltage battery voltage / current and converting the voltage / current from the solar panel string to the high voltage battery voltage / current can be easily achieved.
[0041] In one embodiment, the differential power processing converter is a flyback converter.
[0042] In one embodiment, the battery voltage of the low voltage battery is between 12V and 48V, in particular 12V. However, the low voltage battery is generally not limited to this voltage range. In one embodiment, the battery voltage of the high voltage battery is between 60V and 1000V, in particular 400V, 800V, 900V or even higher. However, in general, the high voltage battery is not limited to this voltage range.
[0043] In one embodiment, the controller is adapted (e.g. programmed) to operate the differential power processing converters (i.e. one, some or all differential power processing converters) in at least one other mode (also referred to as "charging mode" without loss of generality) in which the amount of energy flowing through the differential power processing converters is increased above the DPP level, in particular maximized. This is particularly useful in certain specific use cases, for example when the state of charge SoC of the low voltage battery is low and needs to be charged. The low voltage battery powers ECUs and sensors that are highly safety-related and require a high level of reliability.
[0044] The object is also achieved by a method for charging a low voltage battery and a high voltage battery of an electric vehicle according to any of the preceding claims, wherein when the solar panels generate electrical energy, the low voltage battery is charged by a differential power processing converter and the high voltage battery is charged by a string converter. BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The above-mentioned features and advantages of the present invention and their implementation will now be described in more detail, illustratively, by way of at least one embodiment in the context of one or more of the accompanying drawings.
[0046] Figure 1 An electric vehicle EV is shown, including a low-voltage battery LV and a high-voltage battery HV. DETAILED DESCRIPTION
[0047] The electric vehicle EV comprises a low-voltage battery LV and a high-voltage battery HV. In particular, the high-voltage battery HV can be used to power one or more electric drive motors. The high-voltage battery HV can, for example, have a battery voltage of 400V or 800V. The high-voltage battery HV can, for example, be a lithium-ion battery. The low-voltage battery LV can, for example, be used to power low-voltage electrical loads such as sensors and lights. The low-voltage battery LV can, for example, have a battery voltage of 12V. The low-voltage battery LV can, for example, be a lead-acid battery.
[0048] The electric vehicle EV also includes a plurality of solar panels PV i , where n>2 solar panels PV1, PV2, ..., PV n Solar panels PV1, PV2, ..., PV n-1 The corresponding negative output terminal O neg Connect to solar panels PV2, PV, ..., PV n The positive output terminal O pos . Solar panels PV1, PV2, ..., PV n-1 The corresponding negative output terminal O neg Connect to solar panels PV2, PV, ..., PV n The positive output terminal O pos The positive output terminal O of the solar panel PV1 pos (PV1) (It is not connected to the negative output terminal O neg (PV2) to O neg (PV n ) are used as a series string of solar panels PV1, PV2, ..., PV n The positive output terminal of the nth solar panel PV n The negative output terminal O neg (PV n ) (It is not connected to the positive output terminal O pos (PV1) to O pos (PV n-1 ) as solar panels PV1, PV2, …, PV n The negative output terminal of the series string.
[0049] The positive output terminal O of the solar panel PV1 pos (PV1) is connected to the positive input terminal I of the supply side of the DC-DC converter ("string converter") SC. pos , the converter can be implemented as a boost converter, for example, similar to FIG. 3 of the article by Hoejeong Jeong et al. The negative input terminal I neg Connected to a first reference potential, such as the ground terminal GND1. The load-side positive output terminal O of the string converter SCpos Connected to the positive terminal of the high voltage battery HV, and the load side negative output terminal O of the string converter SC neg Connected to a second reference potential, for example ground GND2. The operation of the string converter SC, in particular at least the operation of its electronic switches, can be controlled by a controller CTL.
[0050] The negative electrode of the high voltage battery HV is connected to a third reference potential, such as the ground terminal GND3. The second reference potential GND2 may be equal to the third reference potential GND3. This may also be expressed as making the load-side negative output terminal O of the string converter SC neg Connected to the negative electrode of the high voltage battery HV. The first reference potential GND1 may be equal to the second reference potential GND2.
[0051] The electric vehicle EV further includes n differential power processing converters DPP1, ..., DPP n , which can be implemented as a flyback converter, for example, similar to FIG. 3 of the article by Hoejeong Jeong et al. Each differential power processing converter DPP i The load side input terminal I pos (DPP i ) and I neg (DPP i ) connected to the corresponding solar panel PV i The corresponding output terminal O pos (PV i ) and O neg (PV i ), where i=1,…,n, i.e., the positive input terminal I pos (DPP i ) connected to the positive output terminal O pos (PV i ) and the negative input terminal I neg (DPPi) connected to the negative output terminal O neg (PV i ).
[0052] All differential power processing converters DPP i The load side positive output terminal O pos (DPP i ) is connected to the positive terminal of the low voltage battery LV. All differential power processing converters DPP i The negative output terminal O on the load side neg (DPP i ) is connected to the negative pole of the low voltage battery LV and to the negative pole of the high voltage battery HV, which in turn is connected to a fourth reference potential, for example GND4. The fourth reference potential GND4 may be different from the third reference potential GND3, in particular if the string converter SC comprises a galvanic isolation.
[0053] Differential Power Processing Converter DPP i The operation of the differential power processing converter DPP, in particular at least the operation of its electronic switches, can be controlled by the controller CTL. i Can be controlled individually by controller CTL. Solar panel PV i , Differential Power Processing Converter DPP i Together with the string converter SC, it forms a PV-bus direct connection architecture with a differential power handling converter.
[0054] In particular, if the electric vehicle EV is a plug-in hybrid vehicle or a full battery electric vehicle, the high voltage battery HV can be charged by connecting the on-board battery charger to the charging station by wireless or wired charging. Typically, the battery charger includes the function of a DC-DC converter to convert the lower voltage level of the supply voltage applied by the charging station to the higher battery voltage level of the high voltage battery HV.
[0055] Alternatively, the battery charger can be used as a string converter SC, in particular during periods when the electric vehicle EV is not connected to a charging station. In particular, the DC-DC converter of the battery charger is implemented as a boost converter controlled by a PWM signal. By varying the PWM signal, the boost converter can be adapted to increase the voltage level of the charging station or the output terminal O as required. pos The voltage level of (PV1) is converted to the voltage level of the high voltage battery HV.
[0056] Therefore, when the solar panel PV i When generating electrical energy, the low voltage battery LV is converted by the differential power processing converter DPP i The high voltage battery HV is charged by the string converter SC.
[0057] The controller CTL is suitable for controlling the differential power processing converter DPP in a (nominal) DPP mode i In this mode, only the solar panel PV i The charging current to the low voltage battery LV is generated only when the voltage provided is unbalanced. Optionally, the controller CTL can also be adapted to control the differential power processing converter DPP in the charging mode. i In this mode, the charging current to the low voltage battery LV is increased above the DPP mode level and is applied not only when the solar panel voltage is unbalanced, but also, for example, continuously.
[0058] Of course, the invention is not limited to the described embodiments.
[0059] Reference numerals list
[0060] CTL Controller
[0061] DPP i The i-th flyback converter
[0062] EV Electric Vehicle
[0063] GND1 first reference potential
[0064] GND2 second reference potential
[0065] GND3 third reference potential
[0066] GND4 fourth reference potential
[0067] HV High Voltage Battery
[0068] I neg Negative input terminal
[0069] I pos Positive input
[0070] LV low voltage battery
[0071] O neg Negative output terminal
[0072] O pos Positive output terminal
[0073] PV i The i-th solar panel
[0074] SC string converter
Claims
1. An electric vehicle (EV), comprising: - Low voltage battery (LV) and high voltage battery (HV), -n>1 solar panel (PV i ) of the series string (PV i -PV n ), -n Differential Power Processing Converters (DPP i ),as well as - String Converter (SC), in - Each differential power processing converter (DPP i ) on the supply side positive input terminal (I pos ) connected to the corresponding solar panel (PV i ) of the positive output terminal (O pos ), and the negative input terminal of the supply side (I neg ) is connected to the corresponding solar panel (PV i ) of the negative output terminal (O neg ), -Differential Power Processing Converter (DPP i ) of the load side positive output terminal (O pos ) is connected to the positive terminal of the low voltage battery (LV), -Differential Power Processing Converter (DPP i ) of the load side negative output terminal (O neg ) is connected to the negative terminal of the low voltage battery (LV), - Supply side positive input terminal of the string converter (SC) (I pos ) connected to the solar panel (PV i ) of the series string (PV i -PV n ) of the positive output terminal (O pos ), and the negative input terminal of the supply side (I neg ) is connected to the reference potential (GND1), - The load side positive output terminal (O pos ) is connected to the positive terminal of the high voltage battery (HV), - The negative output terminal (O neg ) is connected to the reference potential (GND2), and - Controller (CTL) suitable for controlling string converters (SC) and differential power processing converters (DPP i ) operation.
2. An electric vehicle (EV) according to any one of the preceding claims, further comprising a battery charger connected to the high voltage battery (HV).
3. The electric vehicle (EV) according to claim 2, wherein: This battery charger is an AC charger.
4. An electric vehicle (EV) according to any one of claims 2 to 3, wherein: The string converter (SC) is the battery charger.
5. The electric vehicle (EV) according to claim 4, wherein: The battery charger is adapted to convert the voltage from the external charging source into a high voltage battery (HV) voltage and to convert the voltage from the solar panel string (PV i -PV n ) voltage into the high voltage battery (HV) voltage and back.
6. An electric vehicle (EV) according to any one of the preceding claims, wherein A string converter (SC) is a boost converter.
7. An electric vehicle (EV) according to any one of the preceding claims, wherein Differential Power Processing Converter (DPP i ) is a flyback converter.
8. An electric vehicle (EV) according to any one of the preceding claims, wherein The battery voltage of a low voltage battery (LV) is between 12V and 48V, specifically 12V.
9. An electric vehicle (EV) according to any one of the preceding claims, wherein: The battery voltage of a high voltage battery (HV) is between 60V and 1000V, in particular between 400V and 800V.
10. An electric vehicle (EV) according to any one of the preceding claims, wherein The controller (CTL) is adapted to operate the differential power processing converter (DPP) in at least one additional mode i ), in this other mode, flows through the differential power processing converter (DPP i ) to above the differential power handling level.
11. A method for charging a low voltage battery (LV) and a high voltage battery (HV) of an electric vehicle (EV) according to any one of the preceding claims, wherein: When the solar panel (PVi) generates electricity, the low voltage battery (LV) is powered by a differential power processing converter (DPP i ) is charged, and the high voltage battery (HV) is charged by the string converter (SC).