Circuit device

Abstract

The invention relates to a circuit device (2) in which up to four regenerative energy sources, in particular PV modules (PV1,..., PV4), are connected on the input side and up to three electric loads (L1, L2, L3) are connected on the output side as consumers, wherein by opening and closing switches in a controlled manner, the energy sources can be switched to the outputs (O1, O2, O3) in a variable configuration in order to achieve a parallel circuit of the energy sources (PV1,.., PV4) during operation or in order to achieve a separate simultaneous supply to multiple loads (L1, L2, L3).

Description

[0001] CIRCUIT DEVICE

[0002] The invention relates to a circuit device.

[0003] Water heaters are well known in the art. These are used to heat drinking or domestic water to a desired temperature and to maintain a certain amount of hot water via an integrated storage tank. Water heaters can be installed centrally within a building's electrical system, either for the entire building or locally for individual draw-off points. Typically, water heaters are electrically operated, with a heating element powered by the electrical grid used to heat the hot water.

[0004] DE 10 2020 102 532 A1 describes a circuit device for supplying a hot water generator from a renewable energy source, in particular a solar cell or a wind turbine, in which output terminals of the energy source are connected to an adaptation circuit whose output current circuit is guided through a heating resistor of the hot water generator, wherein the adaptation circuit is controlled via a control circuit such that the current flow through the heating resistor corresponds to a predetermined power output to the heating resistor and that, alternatively or additionally, operation of the hot water generator can be carried out via a mains supply.

[0005] Based on this prior art, the inventors have now set themselves the task of creating a circuit device for supplying power from a renewable energy source, in which a parallel connection of energy sources during operation as well as a separate, simultaneous supply of multiple consumers can be achieved without having to change existing electrical connections. This task is solved by the features of patent claim 1. Further advantageous embodiments of the invention are the subject of the subclaims. These can be combined with one another in a technologically expedient manner. The description, particularly in conjunction with the drawings, further characterizes and specifies the invention.

[0006] According to the invention, a switching device is created in which up to four regenerative energy sources, in particular PV modules, are connected on the input side and up to three electrical loads are connected as consumers on the output side, wherein by means of targeted opening and closing of switches, the energy sources can be switched to the outputs in a variable configuration in order to achieve a parallel connection of the energy sources during operation or a separate, simultaneous supply of several loads.

[0007] The circuit device according to the invention can be used for energy management or surplus management, in that energy from a renewable energy source, in particular from a photovoltaic system, can be used to supply, for example, a hot water generator as the first electrical load. Energy not used by the hot water generator can be supplied to another consumer, for example in the form of an accumulator as a second electrical load, or to the power grid via an inverter as a third electrical load. Using switches, the PV modules can be connected to the system outputs in a variable configuration. This enables parallel connection of PV modules during operation as well as separate, simultaneous supply of multiple consumers.

[0008] According to one embodiment of the invention, on the input side

[0009] Switch up to four 60- or 72-cell PV modules as energy sources (connected), which supply up to three electrical loads as consumers, preferably in the form of a hot water generator, an accumulator or an inverter for feeding into the power grid, at the outputs.

[0010] Accordingly, the circuit device according to the invention is used as an energy management system for energy generation, energy distribution, and energy consumption. The dimensioning of the photovoltaic system corresponds to a so-called balcony power plant. Preferably, the energy generated by the photovoltaic system is stored in the hot water generator. If the hot water generator cannot consume electrical energy, the accumulator, for example, can be charged. If the accumulator is also unable to consume electrical energy, the energy is fed into the power grid.

[0011] According to a further embodiment of the invention, the targeted opening and closing of switches is based on a prioritization of the outputs and depending on the incoming power of the PV modules, whereby if more power is generated than an electrical load can absorb, a PV module is switched to the next priority output.

[0012] In this way, a specification is made as to how the power of the PV modules is distributed across the different outputs.

[0013] According to a further embodiment of the invention, a terminal of a first photovoltaic module as an energy source is connected to a first output via a first line, a terminal of a second photovoltaic module as an energy source is connected to a second output via a second line, and a terminal of a third photovoltaic module as an energy source is connected to a third output via a third line, wherein a terminal of a fourth photovoltaic module as an energy source is connected via a fourth line to a first switch, the other terminal of which is connected to the second line, and to a fourth switch, the other terminal of which is connected to the first line, the third line being connected to the second line via a second switch and the second line being connected to the first line via a third switch.

[0014] This allows for flexible rerouting of the photovoltaic modules as inputs of the switching device to the various outputs. In addition to the variable parallel connection of PV modules, this connection also serves to specifically rerouting the inputs to the outputs.

[0015] According to a further embodiment of the invention, the further terminals of the photovoltaic modules are connected to ground directly or via reverse polarity protection.

[0016] According to a further embodiment of the invention, the further terminals of the outputs for connection to the electrical loads are each connected to ground via further switches.

[0017] According to a further embodiment of the invention, the positive supply voltages of the PV modules are connected together via two N-channel power MOSFETs each.

[0018] According to a further embodiment of the invention, a control circuit is provided for the gate terminals of the power MOSFETs, which increases an incoming PV voltage via a charge pump with a PWM signal. According to a further embodiment of the invention, the increased voltage is limited by a Zener diode to prevent an overvoltage between the gate and source terminals and a resulting breakdown.

[0019] According to a further embodiment of the invention, the gate of the power MOSFETs is controlled via a push-pull output stage, wherein the push-pull output stage is switched via a logic MOSFET.

[0020] Below, some examples are explained in more detail using the drawings. They show:

[0021] Figure 1 is a first schematic view of a circuit device according to the invention or of a part thereof,

[0022] Figure 2 shows a second schematic view of a circuit device according to the invention or of a part thereof,

[0023] Figure 3 shows a third schematic view of a circuit device according to the invention or a part thereof,

[0024] Figure 4 shows a fourth schematic view of a circuit device according to the invention or a part thereof, and

[0025] Figure 5 is a fifth schematic view of a circuit device according to the invention or a part thereof,

[0026] Figure 6 is a sixth schematic view of a circuit device according to the invention or a part thereof, and

[0027] Figure 7 shows a diagram from a simulation program. In the figures, identical or functionally equivalent components are provided with the same reference numerals.

[0028] The circuit device according to the invention is explained in more detail below with reference to Figure 1. The circuit device 2 serves for energy management or surplus management of electrical energy and is described below in connection with a photovoltaic system. However, the circuit device according to the invention can also be used in connection with other renewable energy sources, such as a wind turbine.

[0029] Up to four 60- or 72-cell PV modules PV1 to PV4 can be connected on the input side via switching device 2. Up to three electrical loads L1 to L3 are connected on the output side as energy consumers. These can be a hot water tank L1, an accumulator switching device L2, or an inverter L3.

[0030] By using switches, as explained in detail below, the PV modules PV1 to PV4 can be switched to the system outputs in a variable configuration. This enables parallel connection of the PV modules PV1 to PV4 during operation as well as separate, simultaneous supply to several consumers or electrical loads L1 to L3. If the PV modules PV1 to PV4 generate more power than, for example, the electrical load L1 can handle, one PV module is switched to the next load L2. The switching behavior can be based on the prioritization of the outputs of the electrical loads L1 to L3. According to the invention, the PV modules PV1 to PV4 can be switched in a variable configuration, so that separate, simultaneous supply to several consumers is possible during operation.

[0031] An exemplary structure of the circuit device 2 according to the invention is shown in Figure 2.

[0032] It can be seen that a connection of the first photovoltaic module PV1 is connected to a first output O1 via a line 6. Furthermore, a connection of the second photovoltaic module PV2 is connected to a second output O2 via a line 8 and a connection of the third photovoltaic module PV3 is connected to a third output O3 via a line 10. A connection of the fourth photovoltaic module PV4 is connected via a line 12 to a switch SWI1, the other connection of which is connected to line 10, and to a switch SWI4, the other connection of which is connected to line 6. Furthermore, line 10 is connected to line 8 via switch SWI2 and line 8 is connected to line 6 via switch SWI3.

[0033] The other terminals of the photovoltaic modules PV1 to PV4 can be connected to ground directly or, as shown in Figure 2, via a reverse polarity protection 4.

[0034] Outputs 01 to 03 can be connected to electrical loads L1 to L3, as shown above with reference to Figure 1. For this purpose, the other terminals of outputs 01 to 03 are each connected to ground via switches SW01, SW02, and SW03.

[0035] With reference to Figures 3A to 3F, an exemplary configuration for selecting switch positions is shown below, which can be implemented in operation with two photovoltaic modules and two loads. In this example, outputs O2 and O3 are each supplied with a PV module, which can be connected in various ways. The assignment of the reference symbols of the switches used follows the illustration in Figure 2, but has been omitted from Figures 3A to 3F for reasons of clarity.

[0036] In Figure 3A, module PV2 is assigned to output 02. Module PV1 is assigned to output 03 via the closed switches SWI4 and SWI1. Switches SWI2 and SWI3 are open. The other switches SW02 and SW03 are also closed, creating a closed circuit. The other switch SW01 is open because there is no load connected to the corresponding output 01.

[0037] In Figure 3B, the PV3 module is assigned to output 03. The PV1 module is assigned to output 02 via the closed switch SWI3. The switches SWI1, SWI2, and SWI4 are open. The switches SW02 and SW03 are closed, and the switch SW01 is open.

[0038] In Figure 3C, module PV1 is assigned to output O2 via the closed switch SWI3. Module PV4 is assigned to output O3 via the closed switch SWI1. Switches SWI2 and SWI4 are open. Switches SW02 and SW03 are closed, and switch SW01 is open.

[0039] In Figure 3D, module PV3 is assigned to output 03. Module PV3 is assigned to output 03. Module PV2 is assigned to output 02. Switches SWI1, SWI2, SWI3, and SWI4 are open. Switches SW02 and SW03 are closed, and switch SW01 is open. In Figure 3E, module PV2 is assigned to output 02. Module PV4 is assigned to output 03 via the closed switch SWI1. Switches SWI2, SWI3, and SWI4 are open. Switches SW02 and SW03 are closed, and switch SW01 is open.

[0040] In Figure 3F, module PV3 is assigned to output 03. Module PV1 is assigned to output 02 via the closed switches SWI4 and SWI3. Switches SWI1 and SWI2 are open. Switches SW02 and SW03 are closed, and switch SW01 is open.

[0041] In addition to the targeted redirection of the PV modules to specified outputs shown in Figures 3A to 3F, the switches can also be used for variable parallel connection of PV modules.

[0042] The parallel connection of the input-side PV modules is achieved using the setup shown in Figure 4. The positive supply voltages of the PV modules are connected together via N-channel MOSFETs. Taking the body diode into account, two N-channel MOSFETs are connected in series. This is necessary to prevent interference currents from flowing through the body diode when the switch is closed, for example, if one of the neighboring PV modules is not connected or has a lower voltage.

[0043] For the gate of the power MOSFETs of the switches SWI1 to SWI4, corresponding control circuits are provided, which are briefly explained below in various embodiments.

[0044] An embodiment of the control circuit 14 for generating the gate control voltage is shown in Figure 5. For this purpose, the capacitor C1 is cyclically charged to the PV voltage V+, whereby in the next step the voltage at C1 is increased to twice the PV voltage by closing the switch M11 with a PWM signal. The diode D2 charges the capacitor C2 to this double PV module voltage, although this charging process requires a certain charging time. The increased voltage is applied to the gate GATE of the PV input to be switched, whereby a Zener diode D3 limits the control voltage (to 12 volts here) and thus prevents gate-source breakdown. By controlling the logic MOSFET M13, the gate voltage of the power MOSFETs can be pulled to ground potential, which opens them and removes the parallel connection of the PV modules.

[0045] Another embodiment of the control circuit 14 for generating the gate control voltage is shown in Figure 6. The positive supply voltages of the PV modules are interconnected via anti-serial N-channel MOSFETs via discretely constructed gate drivers with charge pumps.

[0046] In this principle, the first step is to charge capacitor C15 to the supply voltage V+ via diode D4 while switch Q12 is closed. Subsequently, switch Q12 is opened, causing the supply voltage V+ to be applied to the negative potential of capacitor C15. Since the capacitor was previously charged to the supply voltage, twice the operating voltage is now applied to its positive potential. This is used to charge a second capacitor C19 via diode D8. The diodes ensure the one-sided charging of the capacitors and prevent reverse current.

[0047] When capacitor C19 is charged, capacitor C15 is discharged, which is why it must be periodically recharged. For this purpose, a PWM signal is used to control switch Q12, cyclically charging capacitor C15 and generating twice the operating voltage across capacitor C19. The doubled operating voltage is used to supply the gates G1 to G4 (see Figure 4) of the power MOSFETs, which are controlled by the push-pull output stage consisting of N-channel MOSFET Q19 and P-channel MOSFET Q20. Using a push-pull output stage allows for higher drive currents, allowing the power MOSFETs to switch faster.

[0048] The push-pull output stage is switched via the logic MOSFET Q16. When this is in the open state, the increased operating voltage is applied to the gate of the push-pull output stage, which is limited to 15 V above the supply voltage V+ by a Zener diode Z. If a positive voltage is applied to the gate of the push-pull output stage, the associated N-channel MOSFET Q19 switches, whereby the increased operating voltage, reduced by the specific threshold voltage of the logic MOSFET, is applied to the gate of the power MOSFETs, and the power MOSFETs switch. If switch Q16 is in the closed state, however, the ground potential is applied to the gate of the push-pull circuit, which discharges the gate of the power MOSFETs via the P-channel MOSFET Q20 and opens the power MOSFETs.

[0049] As in the previous implementation of Figure 5, according to Figure 6, the incoming PV voltage V+ is doubled via a bootstrapping circuit with a PWM signal. The increased voltage is limited using a Zener diode to prevent an overvoltage between the gate and source terminals and resulting breakdown.

[0050] This extension uses a discrete driver circuit with a push-pull stage consisting of an N-channel and a P-channel MOSFET to accelerate the switching of the MOSFET power switches. The driver stage is controlled by an N-channel MOSFET. The current flow is limited by a series resistor, with a faster charging or discharging option available via a diode configuration.

[0051] The process of increasing the voltage is shown in Figure 7. The PV module voltage, here designated by reference numeral 18, is increased by using the

[0052] PWM signals, designated here by reference numeral 16, are boosted to a voltage higher than 12 or 15 volts, for example, to drive the gate of the MOSFETs, shown here by reference numeral 20. The features stated above and in the claims, as well as those shown in the figures, can be advantageously implemented both individually and in various combinations. The invention is not limited to the described embodiments, but can be modified in many ways within the scope of expert knowledge.

Claims

Claims: Circuit device (2) in which up to four renewable energy sources, in particular PV modules (PV1, ..., PV4), and up to three electrical loads (L1, L2, L3) are connected as inputs, wherein the energy sources can be switched to the outputs (01, 02, 03) in a variable configuration by selectively opening and closing switches in order to achieve a parallel connection of the energy sources (PV1, ..., PV4) during operation or a separate, simultaneous supply of several loads (L1, L2, L3). Circuit device (2) according to claim 1, in which up to four 60- or 72-cell PV modules are connected as energy sources (PV1, ...) via switches on the input side., PV4) are connected, which supply up to three electrical loads (L1, L2, L3) as consumers, preferably in the form of a water heater, a battery, or an inverter for feeding into the power grid, at the outputs (01, 02, 03). Circuit device (2) according to claim 2, in which the targeted opening and closing of switches is based on a prioritization of the outputs (01, 02, 03) and depending on the incoming power of the PV modules (PV1, ..., PV4), wherein if more power is generated than an electrical load (L1, L2, L3) can absorb, a PV module is switched to the next-priority output. Circuit device (2) according to one of claims 1 to 3, in which a connection of a first photovoltaic module (PV1 ) as an energy source is connected via a first line (6) to a first output (01 ), a connection of a second photovoltaic module (PV2) as an energy source. a second line (8) is connected to a second output (02), and a connection of a third photovoltaic module (PV3) as an energy source is connected via a third line (10) to a third output (03), wherein a connection of a fourth photovoltaic module (PV4) as an energy source is connected via a fourth line (12) to a first switch (SWI1), the other terminal of which is connected to the second line (10), and to a fourth switch (SWI4), the other terminal of which is connected to the first line (6), wherein the third line (10) is connected to the second line (8) via a second switch (SWI2) and the second line (8) is connected to the first line (6) via a third switch (SWI3). Circuit device (2) according to claim 4, wherein the further terminals of the photovoltaic modules (PV1, PV4) are connected directly or via a reverse polarity protection device (4) to ground.Circuit device (2) according to claim 4 or 5, wherein the further terminals of the outputs (01, 02, 03) are connected to ground via further switches (SW01, SW02, SW03) for connection to the electrical loads (L1, L2, L3). Circuit device (2) according to any one of claims 4 to 6, wherein the positive supply voltages of the PV modules (PV1, ..., PV4) are interconnected via two N-channel power MOSFETs each. Circuit device (2) according to claim 7, wherein a control circuit (14) is provided for the gate terminals of the power MOSFETs, which increases the incoming PV voltage (V+) via a charge pump with a PWM signal. Circuit device (2) according to claim 8, wherein the increased voltage is limited by means of a Zener diode to prevent an overvoltage between the gate and source terminals and a resulting breakdown. Circuit device (2) according to claim 8 or 9, wherein the gate of the power MOSFETs is driven via a push-pull output stage (Q19, Q20), the push-pull output stage being switched via a logic MOSFET (Q16).

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