Control circuit of a microcontroller for a battery-free photovoltaic system, associated devices and methods
The control circuit addresses the limited lifespan and start-up failures of battery-based photovoltaic systems by regulating voltage and current, ensuring reliable operation without a battery and enhancing system longevity.
Patent Information
- Application Number
- FR2022013992
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-12-20
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2042-12-20
AI Technical Summary
Photovoltaic systems with batteries have limited lifespan due to battery degradation, and they struggle with start-up failures during low irradiance conditions, leading to inefficient and potentially damaging start-up attempts.
A control circuit for a photovoltaic system that includes a dissipation circuit, a voltage regulation circuit, and a comparator to manage the connection of switches, allowing the system to operate without a battery by regulating voltage and current to ensure proper start-up of the controller.
Enables reliable start-up of the photovoltaic system controller at sufficient irradiance levels, preventing start-up failures and extending the system's lifespan by eliminating the need for a battery.
Smart Images
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Abstract
Description
Title of the invention: Control circuit of a microcontroller of a battery-free photovoltaic system, associated devices and method
[0001] The present invention relates to a control circuit for a microcontroller of a photovoltaic system comprising a photovoltaic module. The present invention also relates to an assembly comprising such a control circuit and a microcontroller and to a photovoltaic system comprising these elements. The present invention also relates to a method for controlling a microcontroller using such a control circuit.
[0002] Due to global warming, it is desirable to develop so-called "renewable" energies. Among these, solar energy is particularly interesting.
[0003] One way to benefit from this is to use a photovoltaic module that is adapted to convert energy from photons generated by the sun into electrical energy. To do this, the photovoltaic module comprises a set of photovoltaic cells electrically connected to each other. These cells carry out the photoelectric conversion. This allows the photovoltaic module to operate as a direct current electrical generator in the presence of solar radiation.
[0004] However, to exploit this generated current in a specific use, it is also necessary to take into account the fact that this use requires a voltage between a minimum voltage and a maximum voltage.
[0005] Also, it is known to also use a battery whose role is twofold: on the one hand to serve as a reservoir for the energy produced by the photovoltaic module and on the other hand to serve as a voltage source for the desired use.
[0006] The entire photovoltaic module and battery thus form an autonomous photovoltaic system in the sense that the system is not coupled to the electrical network.
[0007] However, the lifetime of such a photovoltaic system is, in practice, limited by the lifetime of the battery.
[0008] To do this, it would be enough to do without a battery, but at the start of the day, when the irradiance is very low, a start-stop phenomenon takes place.
[0009] Indeed, during the night, the power supplied by the photovoltaic module is zero, and at the very beginning of the day, there is a period during which there is still not enough energy to properly start up the system comprising the photovoltaic module.
[0010] In fact, as soon as a ray of light reaches the photovoltaic module, it quickly generates a voltage higher than the starting voltage.
[0011] However, this start attempt ends in failure because the current produced is still insufficient. This phenomenon is repeated until the current produced is sufficient.
[0012] There is therefore a need for a photovoltaic system that can operate without the use of a battery.
[0013] For this purpose, the description describes a control circuit of a controller of a photovoltaic system comprising a photovoltaic module, the control circuit comprising:
[0014] - an input suitable for being connected to the photovoltaic module,
[0015] - an output suitable for connection to the controller,
[0016] - a circuit for dissipating the power received at the input of the control circuit,
[0017] - a circuit for regulating the voltage received at the input of the control circuit,
[0018] - a comparator, the entire dissipation circuit, the regulation circuit and the comparator forming a starting unit,
[0019] - a first switch having a first position in which the unit of starting unit is connected to the input of the control circuit and a second position in which the starting unit is not connected to the input of the control circuit, the position of the first switch being controllable by a control voltage, and
[0020] - a second switch having a first position in which the input and the output of the control circuit are not connected and a second position in which the input and the output of the control circuit are connected, the position of the second switch being controllable by a control voltage,
[0021] the comparator being capable of comparing the voltage at a point of the dissipation circuit with the voltage at a point of the voltage regulation circuit, each of the points used by the comparator being called a comparison point, the comparator being capable of emitting at the output a control voltage of the two switches depending on the comparison between the value of the voltages of the two comparison points.
[0022] According to particular embodiments, the control circuit has one or more of the following characteristics, taken in isolation or in all technically possible combinations:
[0023] - when the voltage at a point in the voltage regulation circuit is lower than the voltage at a point in the dissipation circuit, the comparator is capable of emitting a control voltage requiring the position of the second switch to be the second position.
[0024] - when the voltage at a point in the voltage regulation circuit is lower than the voltage at a point in the dissipation circuit, the comparator is capable of emitting a control voltage requiring that the position of the first switch is the second position.
[0025] - the dissipation circuit is a bridge having at least two components and a midpoint, the comparison point of the dissipation circuit being the midpoint.
[0026] - the components of the dissipation circuit are in series.
[0027] - the components of the dissipation circuit are two resistors of the same value.
[0028] - the regulation circuit is suitable for ensuring that the voltage at the comparison point of the regulation circuit is equal to the voltage received at the input up to a threshold voltage, the voltage at the comparison point of the regulation circuit being equal to the threshold voltage for a voltage received at the input greater than the threshold.
[0029] - the regulation circuit is a bridge having at least two components and one point middle, the comparison point of the control circuit being the midpoint of the control circuit.
[0030] - the regulation circuit comprises a voltage regulator component.
[0031] - the voltage regulator component is a Zener diode.
[0032] - the regulation circuit is formed by a resistor and a Zener diode in series, the Zener diode having a cathode connected to the midpoint of the regulation circuit.
[0033] - the Zener diode has a Zener voltage, the comparator being supplied by a supply voltage equal to twice the Zener voltage.
[0034] The description also relates to an assembly comprising:
[0035] - a controller of a photovoltaic system comprising a photovoltaic module, And
[0036] - a control circuit as previously described, the controller being connected to the output of the control circuit.
[0037] The description also describes a photovoltaic system comprising:
[0038] - a photovoltaic module,
[0039] - a controller, and
[0040] - a control circuit as previously described, the input of the control circuit being connected to the photovoltaic module and the output of the control circuit being connected to the controller.
[0041] In the present description, the expression “suitable for” means indifferently “adapted for”, “adapted to” or “configured for”.
[0042] Characteristics and advantages of the invention will appear on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings, in which:
[0043] - [Fig.l] [Fig.l] is a block diagram of an example of a photovoltaic system including in particular a controller and a control circuit for this controller, and
[0044] - [Fig.2] [Fig.2] is a schematic representation of the control circuit of the [Fig.l].
[0045] A photovoltaic system 10 is shown schematically in [Fig. 1].
[0046] The photovoltaic system 10 is here a system suitable for converting energy incident solar energy into usable electrical energy in a predefined use.
[0047] For this, as visible in [Fig.l], the photovoltaic system 10 comprises a set of elements including a photovoltaic module 12 and a controller 14.
[0048] The photovoltaic module 12 converts light energy into electrical energy. For this purpose, the photovoltaic module 12 brings together a set of photovoltaic cells.
[0049] The photovoltaic module 12 is capable of delivering an output current which is pro proportional to the irradiance of the light received by the photovoltaic module 12.
[0050] A voltage is also generated on the output of the photovoltaic module 12, this voltage varying as a function of the irradiance. This output voltage of the photovoltaic module 12 is denoted Vmod in the remainder of the description.
[0051] The controller 14 is used to control the various electronic elements of the photovoltaic system 10.
[0052] Among these electronic elements, there may be cited, by way of example, the supervision system, the system deciding from which moment one switches to electricity production mode by the photovoltaic module 12 or components allowing the injection into the network of the electricity produced by the photovoltaic module.
[0053] The controller 14 is here a microcontroller 14.
[0054] As such, the controller 14 requires relatively low operating power to function properly.
[0055] According to a typical non-limiting example, the controller 14 consumes a voltage of 5 V for a current of 20 mA.
[0056] The photovoltaic system 10 also comprises a control circuit 16 of the controller 14.
[0057] The control circuit 16 is interposed between the photovoltaic module 12 and the controller 14.
[0058] This means that the control circuit 16 has an input 16E and an output 16S, the input 16E of the control circuit 16 being connected to the photovoltaic module 12 (more precisely to its output 12S) and the output 16S of the control circuit 16 being connected to the controller 14.
[0059] As its name indicates, the control circuit 16 is used to control the controller 14 and more precisely to control the times when it must operate.
[0060] The control circuit 16 serves, in particular, as a starting circuit for the controller 14.
[0061] In the context described, the control circuit 16 is thus capable of detecting a very low irradiance, of determining whether this irradiance complies with a predefined condition and to trigger the start of the controller 14 when the predefined condition is met.
[0062] The control circuit 16 is shown more precisely in [Fig.2].
[0063] The control circuit 16 comprises a first switch 18, a second com mutator 20, a first bridge 22, a second bridge 24 and a comparator 26.
[0064] Each switch 18 (respectively 20) has two terminals 18B1 and 18B2 (respectively 20B1 and 20B2), one terminal 18B1 (respectively 20B1) being connected to the input 16E of the control circuit 16 and therefore having a potential equal to the output voltage Vmod of the photovoltaic module 12.
[0065] The other terminal 18B2 of the first switch 18 is connected to the two bridges 22 and 24 while that of the second switch 20 is connected to the output 16S of the control circuit 16 and thus to the input 14E of the controller 14.
[0066] According to the example described, each switch 18 and 20 is a controllable switch.
[0067] Each switch 18 and 20 has two positions, an open position in which its two terminals 18B1 and 18B2 (respectively 20B1 and 20B2) are not connected and a closed position in which its two terminals 18B1 and 18B2 (respectively 20B1 and 20B2) are connected.
[0068] The position of each switch 18 or 20 depends on the voltage applied to the switch 18 or 20.
[0069] In this case, it will appear later that the voltage applied to switches 18 and 20 is the same, since it comes from comparator 26. Comparator 26 is thus able to simultaneously control the position of the two switches 18 and 20.
[0070] The first switch 18 is, furthermore, inverse in the sense that the default position is the position in which the input 16E of the control circuit 16 is connected to the dissipation circuit 22.
[0071] The first bridge 22 comprises two components 28 and 30 in series, two ends 22E1 and 22E2 and a midpoint PMI.
[0072] The second bridge 24 comprises two components 32 and 34 in series, two ends 24E1 and 24E2 and a midpoint PM2.
[0073] The first end 22E1 or 24E1 of each bridge 22 or 24 is connected to the first switch 18 and thus connected to the input 16E of the control circuit 16. The first end 22E1 or 24E1 of each bridge 22 or 24 is, therefore, at a potential equal to the output voltage Vmod of the photovoltaic module 12.
[0074] The second end 22E2 or 24E2 of each bridge 22 or 24 is connected to ground.
[0075] The voltage between the ends 22E1 and 22E2 (respectively 24E1 and 24E2) of each bridge 22 or 24 is the output voltage Vmod of the photovoltaic module 12.
[0076] Due to the aforementioned connections, the two bridges 22 and 24 are in a confi-
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[0091] parallel configuration. In the case of the first bridge 22, the two components 28 and 30 are each a resistor. The resistor 28 of the first bridge 22, the terminals of which are connected on the one hand to the first end 22E1 of the first bridge 22 and on the other hand to the midpoint PMI, is called in the remainder of the description “first resistor 28”. The value of the first resistor 28 is noted RL The other resistor 30 whose terminals are connected on the one hand to the second end and on the other hand to the midpoint is called in the remainder of the description “second resistor 30”. The value of the second resistor 30 is noted R2. Due to this configuration, the first bridge 22 forms a voltage divider. This implies that the midpoint voltage PMI of the first bridge 22 is equal to the product of the voltage between the ends 22E1 and 22E2 of the first bridge 22 with the ratio between the value R2 of the second resistor 30 and the sum of the value RI of the first resistor 28 and the value R2 of the second resistor 30. As the voltage across the terminals of the first bridge 22 is the output voltage Vmod of the photovoltaic module 12, it comes: V ----------- V “ RI+R2 Vmod Where VPMi is the midpoint voltage PMI of the first bridge 22. In the case of the second bridge 24, the two components 32 and 34 are a resistor and a Zener diode. The resistor 32 of the second bridge 24, the terminals of which are connected on the one hand to the first end 24E1 and on the other hand to the midpoint PM2, is called in the remainder of the description “third resistor 32”. The value of the third resistor 32 is noted R3. Zener diode 34 has an anode 34A and a cathode 34C. A Zener diode is a semiconductor component which, unlike conventional diodes, has the particularity of being able to allow current to pass in both directions under certain conditions. In the anode-cathode direction of flow, a Zener diode 34 behaves like a conventional diode. The associated threshold voltage is usually of the order of 0.6 V. In the reverse direction (cathode to anode), the current only flows when the voltage value across the Zener diode 34 (in this case, the reverse voltage) has reached a threshold. This effect is often called the avalanche effect. The reverse voltage corresponding to the limit threshold is called breakdown voltage or Zener voltage VZener- Current technology provides access to Zener voltages VZener which vary greatly depending on the Zener diode considered, values between 1.2 V and several hundred Volts can be obtained.
[0092] The anode 34A is connected to the second end 24E2 of the second bridge 14 while the cathode 34C is connected to the midpoint PM2 of the second bridge 24.
[0093] The Zener diode 34 is therefore connected in reverse here, which gives the Zener diode the role of a voltage regulator.
[0094] This implies that the Zener diode 34 becomes conductive when the voltage across its terminals 34C and 34A reaches the Zener voltage VZener- When the voltage applied across its terminals 34C and 34A exceeds the Zener voltage VZener, the Zener diode 34 maintains the voltage across its terminals 34C and 34A at the value of the Zener voltage VZener-
[0095] The comparator 26 comprises supply terminals 26A1 and 26A2, two inputs and one output 28S.
[0096] The comparator 26 is an active component powered by the voltage applied to its supply terminals 26Al and 26A2.
[0097] The first power supply terminal 26A1 is connected to the output of the photovoltaic module 12 via the first switch 18 and the second power supply terminal 26A2 is connected to ground.
[0098] The supply voltage across the terminals of comparator 26 is therefore the output voltage Vmod of the photovoltaic module 12,
[0099] The role of comparator 26 is to compare the potential difference between its two inputs 26E1 and 26E2.
[0100] The first input 26E1 of the comparator 26 is denoted by a “-” sign in [Fig.2] while the second input 26E2 of the comparator 26 is denoted by a “+” sign in [Fig.2]. As a result, the value of the voltage on the first input 26E1 of the comparator 26, respectively on the second input 26E2 of the comparator 26, is denoted V-, respectively V+.
[0101] The comparator 26 is capable of carrying out a comparison between the value V- of the voltage on the first input 26E1 and the value V+ of the voltage on the second input 26E2 and of emitting at the output a signal depending on the sign of the difference between the value V- of the voltage on the first input 26E1 and the value V+ of the voltage on the second input 26E2.
[0102] The output of comparator 26 thus takes two voltage values, a first value corresponding to a negative difference and a second value corresponding to a positive difference.
[0103] More precisely, when the value V- of the voltage on the first input 26E1 is greater than the value V+ of the voltage on the second input 26E2, the output of the comparator 26 is at the first value, this first value being a zero voltage, which corresponds to 'sunrise'.
[0104] Conversely, when the value V- of the voltage on the first input 26E1 is less than or equal to the voltage on the value V+ of the voltage on the second input 26E2, the output is at the second value, this second value being the supply voltage, i.e. the output voltage Vmod of the photovoltaic module 12.
[0105] As indicated schematically by arrow 36 in [Fig.2], the output voltage of comparator 26 makes it possible to control the position of the second switch 20.
[0106] Thus, when the output of the comparator 26 is at the first value (zero voltage), the second switch 20 is set or is in the open position whereas, when the output of the comparator 26 is at the second value (Vmod), the second switch 20 is set or is in the closed position.
[0107] The position of the second switch 20 thus depends on the comparison between the value V- of the voltage on the first input 26E1 and the value V+ of the voltage on the second input 26E2.
[0108] In the assembly of [Fig.2], the second input 26E2 is connected to the midpoint of the first bridge 22 and the first input 26E1 is connected to the midpoint of the second bridge 24.
[0109] The comparator 26 thus performs a comparison between the value y and the voltage across the terminals of the Zener diode.
[0110] The operation of the control circuit 16 is now described with reference to a start-up of the controller 14 at sunrise in the morning.
[0111] The purpose is to ensure that the controller 14 starts when enough sunlight illuminates the photovoltaic module 12 to avoid a start-stop phenomenon.
[0112] Indeed, since at night, the power supplied by the photovoltaic module 12 is zero, at the very beginning of the day, there is a period during which there is not yet enough energy to properly start the controller 14.
[0113] This is due in particular to the fact that at the first light of day, a photovoltaic cell quickly generates a voltage higher than the starting voltage of the controller 14, so that it tries to start. But, the current produced is then negligible, so that the controller 14 cannot start and so on until the current produced is sufficient.
[0114] Such a start may damage the controller 14.
[0115] Also, it may be chosen that the controller 14 will only be started when a certain power is available.
[0116] In the example described, the power threshold is broken down into a current limit value to be delivered and a voltage limit value.
[0117] In other words, a voltage start threshold and a current start threshold are used.
[0118] To obtain these values, taking into account the typical values mentioned above,
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[0132] previously (voltage of 5 V for a current of 20 mA), it is useful to take a margin, this margin depending on the case. For example, a voltage value of 10 V and a current of 50 mA are chosen here. This means that the control circuit 16 here seeks to start the controller 14 only when the voltage and current supplied by the photovoltaic module 12 are respectively at the voltage start threshold (10 V) and the current start threshold (50 mA). To explain how the control circuit 16 performs this function, it should be recalled that the comparison voltage with the voltage V- on the first input 26E1 of the comparator 26 is permanently yrr R l+«2 v mod The voltage applied to the terminals of the Zener diode is here the output voltage of the photovoltaic module 12 Vmm} but the value V- of the voltage on the first input 26E1 of the comparator 26 will depend on the operating regime of the Zener diode. When the voltage across the Zener diode is lower than the Zener voltage V zener, the Zener diode blocks the current and the voltage across the Zener diode follows the output voltage of the photovoltaic module 12 Vmod. This means that V - = V)wd in this regime. Therefore, in this regime, the voltage across the Zener diode is permanently higher than the comparison voltage ..Æ..... y Æ1+Æ2 mod Thus, the comparator 26 outputs the first value (zero voltage) and the second switch 20 is in the open position. When the voltage across the Zener diode is higher than the Zener voltage V Zener, the Zener diode lets the current flow and the voltage across the Zener diode no longer follows the module voltage but remains at the Zener voltage VZener- This implies that the value V- of the voltage on the first input 26E1 remains fixed at the Zener voltage VZener- In parallel, the comparison voltage is always -yy—y So, when the module voltage exceeds the Zener voltage VZener, the comparator 26 compares the value of the Zener voltage VZener to the value V When the value V} is less than VZener, the comparator 26 outputs the first value (zero voltage) and the second switch 20 is (or is put) in the open position whereas, when the value V ^ is greater than VZener, the comparator 26 outputs the second value (Vmod) and the second switch 20 is (or is put) in the closed position. There are thus three operating regimes which are briefly reviewed here. When the module voltage Vmod is between 0 and the Zener voltage VZener, the
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[0143] Zener diode is in a blocked state and comparator 26 outputs the first value (zero voltage). When the module voltage Vmod is between the Zener voltage VZener and ^Zm >r an avalanche C"Ct occurs in the Zener diode but comparator 26 always outputs the first value. When the module voltage Vmod is greater than or equal to :r, an effect avalanche still occurs in the Zener diode but comparator 26 outputs the second value Vmod). To take a numerical example, it is assumed that the Zener voltage VZener is equal to 5V and that the resistance values of the first resistor 28 and the second resistor 30 are equal (RI = R2). For optimal operation of comparator 26, it will also be used for the supply voltage of comparator 26 equal to twice the Zener voltage VZener, i.e. 10 V here. The three previous regimes then become the following ones. When the module voltage is between 0 and 5 V, the Zener diode is in a blocked state and comparator 26 outputs the first value (zero voltage). When the module voltage is between 5 V and 10 V, an avalanche effect occurs in the Zener diode but comparator 26 always outputs the first value. When the module voltage is greater than or equal to 10 V, in the presence of an avalanche effect, comparator 26 outputs the second value (Vmod). From the point of view of the second switch 20 or the output of the comparator 26, there are only two regimes: a first regime in which the module voltage is less than 10 V with the second switch 20 in the open position and a second regime in which the module voltage is greater than or equal to 10 V with the second switch 20 in the closed position. More generally, if we abstract from the particular numerical values mentioned above, the control circuit 16 operates according to a first regime in which the module voltage is lower than ÆliSZ y with |c second switch 20 in the R2 r Zener open position and a second regime in which the module voltage is greater than or equal to y with |c second switch 20 in the position closed. It is therefore only the values of the Zener voltage VZener, the value RI of the first resistor 28 and the value R2 of the second resistor 30 which set the threshold from which the second switch 20 switches from the open position to the closed position.
[0144] Therefore, to obtain a starting threshold at fixed voltage Vseua, this implies that the values RI and R2 of the first resistor 28 RI and of the second resistor 30 R2 and of the Zener voltage VZener are chosen so that there is an equality relationship KJigZv =V ... r Z.ener ' threshold
[0145] With the value of RI = R2 and VZener = 5V, a starting voltage threshold of 10 V is obtained.
[0146] As for the intensity supplied when the voltage exceeds the voltage start threshold Vseuil, it is given by the value of the current flowing in the first bridge 22.
[0147] More precisely, this intensity is, according to Ohm's law, the ratio between the voltage applied to the terminals of the first bridge 22 with the total resistance of the first bridge 22. This is written mathematically as follows:
[0148] j = lmod RI+R2
[0149] This implies that it is desired at the threshold that the following relationship is verified by the current start threshold Iseun:
[0150] j „ 1 threshold ~ fd+7?2
[0151] In the numerical example described, this means that the value of the first resistor 28 and the second resistor 30 is equal to 100 Q to ensure that the current has a value of 50 mA.
[0152] This means that the control circuit 16 ensures that the photovoltaic module 12 delivers both a voltage corresponding to the voltage start threshold Vseuil and a current corresponding to the current start threshold ISeuil-
[0153] Formulated from the point of view of light radiation, this means that the control circuit 16 is capable of determining the minimum irradiance that the photovoltaic module 12 must receive to meet the voltage and current criteria, i.e. the minimum power to supply the controller 14.
[0154] The control circuit 16 thus serves as a power detector to start the controller 14.
[0155] Power below the desired power threshold is dissipated in the first resistor 28 and the second resistor 30.
[0156] At the same time as the controller 14 starts up, this power dissipation must cease.
[0157] Also, when the controller 14 starts, the comparator 26 also controls the first switch 18 to go into the open position (the position which is not the normal position for this first switch 18) and while the second switch 20 is in the closed position.
[0158] This makes it possible to ensure that the assembly of the two bridges and the comparator 26 are disconnected from the input of control circuit 16.
[0159] In other words, the assembly of the two bridges and the comparator 26 is no longer connected to the output of the photovoltaic module 12.
[0160] This assembly therefore serves as a starting unit and the first switch 18 serves to connect / disconnect the starting unit.
[0161] The starter unit remains disconnected all day since the sunshine allows the controller 14 to operate.
[0162] Before the transition to night, the controller 14 ensures that it closes properly and returns the first switch 18 to the closed position to activate the starting unit.
[0163] A time delay for this closure after switching off the controller 14 can be put in place to avoid the risk of unexpected restarting before the night has completely passed.
[0164] It can also be noted here that after switching off the controller 14, the second switch 20 is in the position corresponding to the open state.
[0165] To detect the transition to night, the controller 14 monitors the voltage emitted by the photovoltaic module 12, for example by means of a unit for detecting the voltage of the photovoltaic module 12.
[0166] The controller 14 is thus able to control the position of the first switch 18 as a function of the detected voltage.
[0167] The control circuit 16 therefore has the advantage of making it possible to control the controller 14 and in particular to ensure that it starts up correctly.
[0168] The control circuit 16 is, moreover, a very simple electronic circuit since it comprises only three resistors, a Zener diode and a comparator 26.
[0169] The resulting photovoltaic system 10 is thus adapted to operate without a battery.
[0170] This makes it possible to obtain a better lifespan for the photovoltaic system 10.
[0171] It is of course possible to imagine variants of the control circuit 16 of the [Fig.2] performing the same function.
[0172] For example, the two resistors of the first bridge 22 could have different resistance values.
[0173] According to a variant, the first bridge 22 could comprise several resistors in series, the point called the midpoint then being an intermediate point of the first bridge 22 different from the two ends (here one of the terminals of the middle resistor).
[0174] It could even be envisaged a first bridge 22 comprising resistors in parallel.
[0175] In each case, the first bridge 22 serves as a dissipation circuit for the power received at the input of the control circuit 16 during the first part of the morning.
[0176] As regards the second bridge 24, it could also be considered to use assemblies with more resistances.
[0177] Instead of the Zener diode, a more complex circuit with an assembly of several conventional diodes could be envisaged, in particular to have an adjustable threshold.
[0178] More broadly, any component or circuit allowing the voltage to be regulated at a point of the bridge can be considered here.
[0179] In each case, the first bridge 22 serves as a circuit for regulating the voltage received at the input of the control circuit 16, that is to say a circuit ensuring that the voltage at a point is equal to the voltage received at the input up to a threshold voltage, the voltage at this point being equal to the threshold voltage for a voltage received at the input greater than the threshold.
[0180] It will be understood from the aforementioned variants that the comparator 26 does not necessarily carry out the comparison at the midpoint but rather at a comparison point forming part of the circuit considered.
[0181] Thus, in all the embodiments described, the control circuit 16 comprises a starting unit formed of a dissipation circuit, a voltage regulation circuit and a comparator 26.
[0182] The comparator 26 is capable of comparing the voltage at a comparison point of the dissipation circuit 22 with the voltage at a comparison point of the regulation circuit 24, the comparator 26 being capable of outputting a control voltage for the two switches 18 and 20 depending on the comparison between the value of the voltages of the two comparison points.
Claims
Claims
1. Control circuit (16) of a controller (14) of a photovoltaic system (10) comprising a photovoltaic module (12), the control circuit (16) comprising: - an input (16E) suitable for being connected to the photovoltaic module (12), - an output (16S) suitable for being connected to the controller (14), - a dissipation circuit (22) for the power received at the input (16E) of the control circuit (16), - a regulation circuit (24) of the voltage received on the input (16E) of the control circuit (16), - a comparator (26), the entire dissipation circuit (22), the regulation circuit (24) and the comparator (26) forming a starting unit, - a first switch (18) having a first position in which the starter unit is connected to the input (16E) of the control circuit (16) and a second position in which the starter unit is not connected to the input (16E) of the control circuit (16), the position of the first switch (18) being controllable by a control voltage, and - a second switch (20) having a first position in which the input (16E) and the output (16S) of the control circuit (16) are not connected and a second position in which the input (16E) and the output (16S) of the control circuit (16) are connected, the position of the second switch (20) being controllable by a control voltage, the comparator (26) being able to compare the voltage at a point (PMI) of the dissipation circuit (22) with the voltage at a point (PM2) of the regulation circuit (24), each of the points (PMI, PM2) used by the comparator (26) being called a comparison point (PMI, PM2), the comparator (26) being able to output a control voltage of the two switches (18, 20) depending on the comparison between the value of the voltages of the two comparison points (PMI, PM2).
2. A control circuit according to claim 1, wherein, when the voltage at a point (PM2) of the voltage regulation circuit (24) is lower than the voltage at a point (PMI) of the dissipation circuit (22), the comparator (26) is capable of emitting a control voltage requiring the position of the second switch (20) to be the second position.
3. Control circuit according to claim 1 or 2, in which, when the voltage at a point (PM2) of the voltage regulation circuit (24) is lower than the voltage at a point (PMI) of the dissipation circuit (22), the comparator (26) is capable of emitting a control voltage imposing that the position of the first switch (18) is the second position.
4. Control circuit according to any one of claims 1 to 3, wherein the dissipation circuit (22) is a bridge having at least two components (28, 30) and a midpoint (PMI), the comparison point of the dissipation circuit (22) being the midpoint (PMI).
5. Control circuit according to claim 4, in which the components (28, 30) of the dissipation circuit (22) are in series.
6. Control circuit according to claim 4 or 5, in which the components (28, 30) of the dissipation circuit (22) are two resistors of the same value.
7. Control circuit according to any one of claims 1 to 6, in which the regulation circuit (24) is capable of ensuring that the voltage at the comparison point (PM2) of the regulation circuit (24) is equal to the voltage received at the input up to a threshold voltage, the voltage at the comparison point (PM2) of the regulation circuit (24) being equal to the threshold voltage for a voltage received at the input greater than the threshold.
8. Control circuit according to claim 7, wherein the regulation circuit (24) is a bridge having at least two components (32, 34) and a midpoint (PM2), the comparison point of the regulation circuit (24) being the midpoint (PM2) of the regulation circuit (24).
9. A control circuit according to any one of claims 1 to 8, wherein the regulating circuit (24) comprises a voltage regulating component (34).
10. A control circuit according to claim 9, wherein the voltage regulator component (34) is a Zener diode.
11. A control circuit according to any one of claims 1 to 10, wherein the regulating circuit (24) is formed by a resistor (32) and a Zener diode (34) in series, the Zener diode (34) having a cathode (34C) connected to the midpoint (PM2) of the regulating circuit (24).
12. A control circuit according to any one of claims 10 or 11, wherein the Zener diode (34) has a Zener voltage, the comparator (26) being supplied by a supply voltage equal to twice the Zener voltage.
13. Assembly comprising: - a controller (14) of a photovoltaic system (10) comprising a photovoltaic module (12), and - a control circuit (16) according to any one of claims 1 to 12, the controller (14) being connected to the output (16S) of the control circuit (16).
14. Photovoltaic system (10) comprising: - a photovoltaic module (12), - a controller (14), and - a control circuit (16) according to any one of claims 1 to 12, the input (16E) of the control circuit (16) being connected to the photovoltaic module (12) and the output of the control circuit (16) being connected to the controller (14).