Solar panel disconnect and reactivation system

Abstract

A solar panel disconnect and reactivation system is disclosed. A photovoltaic system (10) is disclosed having an inverter (12), at least one solar panel (SP1) for providing power, and an electrical line for coupling power from the at least one solar panel to the inverter. The photovoltaic system further includes a transmitter (12 T ) for sending a message protocol along the electrical line, where the protocol includes a multi-bit wired signal. The photovoltaic system further includes circuitry for selectively connecting power from the at least one solar panel to the inverter along the electrical line in response to the message protocol.

Description

[0001] This application is a divisional application of Chinese patent application 201710200638.3 entitled “Solar Panel Disconnection and Reactivation System”, filed on March 30, 2017. Technical Field

[0002] Preferred embodiments relate to solar panel systems, and more specifically to the disconnection or reactivation of panel-to-grid connectivity, for example, in relation to security considerations. Background Technology

[0003] Solar panel electrical technology traces back to the discovery of photovoltaic (PV) cells decades ago, but economic and ecological factors currently drive the advantages of its widespread adoption. As a result, solar panel systems have become more efficient, cost-effective, and productive. Along with this progress, aspects of solar panel systems are constantly being considered and improved as regulatory requirements or standards evolve. In this regard, the National Electrical Code (NEC) is a regionally applicable standard for the safe installation of various electrical equipment, typically adopted within states or cities in the United States. The NTC has issued requirements for safety considerations in the environments where PV systems are installed, thereby reducing the risk of electric shock and energy hazards to emergency personnel (such as first responders and others) who may need to work near PV systems. For example, NEC requirements are provided for PVRSEs (PV Quick Shutdown Equipment) and PVRSSs (PV Quick Shutdown Systems), where PVRSSs are used to reduce or shut off energy (i.e., voltage / current) at a specific location within a PVRSE for safety purposes in certain situations. As another example, uninsulated live parts containing the risk of electric shock or high current levels of electrical energy should be located, protected, or enclosed to protect personnel who may be required to activate the actuator from unintentional contact when the PV equipment is energized. As yet another example, it is required that for 30 seconds after the actuator signal, the PVRSS should keep the controlled conductor within limits of no more than 30VDC or 15VAC, 8A, and not exceeding 240 volt-amperes.

[0004] Considering the foregoing, this creates a need to address certain security issues arising from the proliferation of PV systems, and preferred embodiments, explored further below, are oriented toward this need. Summary of the Invention

[0005] In a preferred embodiment, a photovoltaic system is provided. The system includes an inverter, at least one solar panel for providing power, and wires for coupling power from the at least one solar panel to the inverter. The system also includes a transmitter for transmitting a message protocol along the wires, wherein the protocol includes a multibit wireline signal. The system further includes circuitry for selectively connecting power from the at least one solar panel to the inverter along the wires in response to the message protocol.

[0006] Many other innovative aspects and preferred embodiments have also been disclosed and are claimed. Attached Figure Description

[0007] Figure 1 An electrical block diagram of a PV system is described according to a preferred embodiment.

[0008] Figure 2 This describes a message protocol with a single message used to control the connectivity of all solar panels.

[0009] Figure 3 Explanation from Figure 2 A single keep-alive signal (KAS) x An example view.

[0010] Figure 4 Explain the RC of each receiver x The flowchart of a preferred embodiment of method 20 is as follows: the operation of sampling signals on the power grid GR to detect the presence or absence of keep-alive signal flow and respond appropriately.

[0011] Figure 5 This describes the method used to detect the presence of optimal, continuous keep-alive signals and reactivate solar panels (SPs). x A flowchart of a preferred embodiment of a method for an appropriate response to the connection with the power grid GR.

[0012] Figure 6 This instruction is used to detect keep-alive signals and to enable or disable solar panel SPs according to most decoding methods. x An alternative method for connectivity to the power grid GR.

[0013] Figure 7 This describes an alternative message protocol for a persistent keep-alive signal stream, which has a group of S 15-bit keep-alive signals, and the binary value of each signal is different from the other signals in the group. Detailed Implementation

[0014] Figure 1An electrical block diagram of a photovoltaic (PV) system 10 is illustrated according to a preferred embodiment. System 10 includes various aspects known in the art, which are first described herein, followed by additional preferred embodiment aspects described in the remainder of this document. First, considering the former, system 10 includes N solar panels, in... Figure 1 The examples shown are solar panels SP1, SP2, ... up to panel SP. N Each solar panel is typically connected in parallel electrical connections to its respective maximum power point tracker (MPPT) MP1, MP2...MP1. N As is well known, each solar panel SP x Operable to convert incident solar energy (i.e., from the sun) into DC voltage, and each of these MPPT MP x It is a DC-to-DC converter that optimizes each solar panel SP x Matching the remaining portion of the grid GR, which connects energy from multiple panels together and connects to other devices, the other devices are connected to the grid GR. Furthermore, the grid GR connects multiple MPPTs via wired connections, such as... Figure 1 As shown in the series connection diagram, the total potential provided by the overall series path is connected to inverter 12. Inverter 12 converts the DC voltage supplied from the solar panel / MPPT into an AC signal V. AC The latter typically outputs at a certain level (e.g., 110 volts AC) to accommodate the voltage requirements of equipment or devices that will use the power generated by system 10. Finally, note that various other items are known in the art and can be connected to... Figure 1 The power grid includes batteries; however, this type of project is not in... Figure 1 The following is shown in order to focus on the discussion of the remaining preferred embodiments described below.

[0015] In an additional preferred embodiment of the viewing system 10, its wired connection is further enhanced to include means for wired network communication in order to enable access to solar panels SP1 to SP2. N The inverter 12 provides for the rapid disconnection and controlled reactivation of the electrical connections of each component. In this regard, the inverter 12 includes a safety actuator 12. SA The safety actuator 12 SA It could be that when actuated, it will begin to interrupt the flow of energy from the solar panel SP. x The process of supplying power from one or more solar panels to the grid (GR) via electrical, mechanical, or graphical operation buttons or interfaces. Further in this regard, safety actuator 12... SAThis can be a user-operated control, and controlled by, for example, an administrator or other personnel, referring to those who wish to remove the solar panel SP for security purposes (such as when responding to an emergency involving system 10 or a similar situation). x The manager or other personnel supplying electricity to the power grid GR. As another example, safety actuator 12. SA This can be software and / or hardware that detects conditions and operates the safety actuator 12 in response to the absence of user intervention. SA This is to initiate an electrical disconnection process for the solar panel; for example, this could be due to a detected electric arc or electric spike. Additionally, safety actuator 12... SA It can also be operated to control the reconnection or reactivation of the power supply from one or more solar panels to the grid GR. Therefore, the safety actuator 12, as described in detail below... SA Together with other circuits, it provides selective connectivity between solar panel energy and the power grid (GR), where in some instances the connection between the two is enabled and electricity is coupled between the two, while in other instances the connection between the two is interrupted so that electricity is not coupled between the two.

[0016] Furthermore, in a preferred embodiment, the transmitter 12 T Associated with inverter 12, such as being incorporated into the housing of inverter 12 or being connected to inverter 12 via the same wired connection, wherein in Figure 1 For example, transmitter 12 T It is shown connected in parallel with the conductor connected to inverter 12. As described in further detail below, transmitter 12 T Operable to send signals along the power grid GR to facilitate the safety actuator 12 SA The function, that is, when the safety actuator 12 SA When the solar panel connection to the grid GR is disconnected or reactivated, transmitter 12... T Transmitting appropriate signals to achieve this result. Furthermore, in this regard, solar panels SP1, SP2, ..., SP... N Each of them is incorporated into or connected to its respective receiver RC1, RC2, ..., RC N Therefore, the receiver RC x It can also be integrated into their respective solar panels SP x The same wired connection is either inside the housing or connected to the panel, wherein... Figure 1 For example, each of these receivers RC x Shown as being connected to their respective solar panels SP xThe conductors are connected in parallel. Typically, as can be determined by those skilled in the art, transmitter 12... T and receivers RC1, RC2, ..., RC N Each of these can be constructed from various hardware and software to implement the functions of the communication and protocols described in this document.

[0017] Each receiver RC x It was also shown to have its own MPPT MP x The control connections are shown (by arrows); for example, receiver RC1 has control connections to MPPTs MP1, MP2, etc. Through this control, each receiver can send signals to its respective MPPT to electrically isolate its respective solar panel SP. x To prevent power from being supplied to the grid; for example, receiver RC1 can control MPPT MP1 so that solar panel SP1 cannot supply current to inverter 12. Therefore, in this respect, a switching circuit is thus included in each MPPT MP1. x In this way, from the solar panel SP x After MPPT MP x Furthermore, the connection to inverter 12 can be interrupted, such as through an open circuit (e.g., a relay, switch, or other element used to block current flow). Similarly, this circuit can be controlled to reconnect or reactivate the open circuit to restore the connection to the solar panel SP. x Power supply to the power grid GR.

[0018] Safety actuator 12 of inverter 12 used to control the connectivity of solar panels SA In a preferred embodiment, operation is accomplished via a message protocol between the inverter 12 and the solar panels or some other circuitry, wherein, in a preferred embodiment, such circuitry is an MPPT (Multi-Phase Power Transmission Platform) that can disconnect / close the connection between the solar panels (or panel groups) and the power grid GR. In one preferred embodiment, the message protocol uses a single message to control all solar panels, while in alternative preferred embodiments, different messages correspond to respective groups of one or more panels, depending on the protocol, with each group responding to its respective signal. Each of these alternatives is described below.

[0019] Figure 2 This describes a message protocol with a single message used to control the connectivity of all solar panels. For example... Figure 2 As shown, transmitter 12 T Preferably along Figure 1The wired connection transmits a continuous stream of messages, referred to herein as the keep-alive signal. As wired communication, it avoids the various complexities and costs associated with alternatives to wireless communication. In any case, the continuous stream of the keep-alive signal... Figure 2 The signals are shown in the diagram, following each other sequentially in time, wherein each such signal is similar, that is, each such signal contains the same information as the others. As described in further detail later, each receiver RC... x The signal connected to the receiver is evaluated to detect this keep-alive signal, and as long as the detection occurs sufficiently over time, the respective MPPT is reached. x RC receiver x Control enables the corresponding solar panel SP x Continue supplying current to the grid GR. However, if the receiver RC... x If a sufficient number of such keep-alive signals are not detected within a given time period, then the receiver RC... x Each controller has its own MPPT x In order to disconnect their respective solar panels SP x This avoids supplying current to the grid GR. Therefore, in the latter case, safety considerations (such as those from NEC) can be addressed by quickly, effectively, and reliably disconnecting the grid GR from the solar panel SP. x This is achieved through the reception of electricity.

[0020] Figure 3 Explanation from Figure 2 A single keep-alive signal KAS x The unfolded diagram. In a preferred embodiment, each keep-alive signal KAS x It is a 15-bit signal (represented as bits b0 to b1). 14 Each bit is transmitted over a duration of 5 milliseconds (ms), making the entire keep-alive signal KAS... x The transmission period is 75ms. Furthermore, each bit is preferably transmitted by transmitter 12. T Frequency Shift Keying (FSK) modulation is used for transmission. As is known in the field of FSK, each of the binary values ​​is transmitted at a different frequency, where 1 is called the marker frequency f. M And 0 is called the space frequency f S If one of the frequencies is more susceptible to poor channel quality, this frequency differentiation improves appropriate signal detection. Furthermore, when the channel is limited by randomly added noise, encoding the keep-alive signal into a format such as... Figure 3 The 15-bit sequence shown yields 10log 10(15) = 11.8 dB SNR improvement, wherein preferably the sequence is pseudo-orthogonal to any random sequence. Furthermore, note that each keep-alive signal contains only data bits, where no overhead is required to restrict different parts of a data packet or frame, such as separate headers, payloads, and possible accuracy checks (e.g., CRC) or other frame termination fields. Therefore, and as described in detail below, each RC in the receiver... x Evaluation of the power grid GR at frequency f M and f S The signal of any of the signals is used to detect the keep-alive signal. Furthermore, in a preferred embodiment where the keep-alive signal is transmitted without pauses or time intervals between consecutive signals and in the case of continuous phase transitions, a correlator can be implemented in each receiver RC. x Therefore, based on the knowledge of the bit pattern of the keep-alive signal, the keep-alive signal should arrive within a 75ms time window. When the autocorrelation is high, the peak value will be detected by the correlator, thus determining the presence of the keep-alive signal. As described in further detail below, this signal detection will keep the solar panel SP x Or the connectivity of a group of solar panels to the grid GR. Furthermore, through continuous phase change, this detection can be observed at emitter 12. T and receiver RC1 to RC N This occurs without any additional synchronization or message overhead.

[0021] Figure 4 Explain the RC of each receiver x The flowchart describes a preferred embodiment of method 20, which involves sampling signals on the power grid GR to detect the presence or absence of a keep-alive signal flow and responding appropriately. Method 20 begins with system initiation step 22, which illustrates the startup of system 10 according to principles known in the art. Thus, assuming appropriate operation, then in step 22, each solar panel SP... x Provide electrical energy to its corresponding MMPT MP x And provide any power conversion required to supply energy via solar panels also known in the art, each corresponding MPPT MP x The corresponding electrical signal is supplied to the power grid GR. Meanwhile, it is assumed that safety actuator 12... SA If not activated, inverter 12 supplies power to the grid GR as follows: Figure 2 The diagram shows a recurring, ongoing sequence of keep-alive signals. Next, method 20 continues from step 22 to step 24.

[0022] In step 24, each receiver RC xThe parameter to be displayed as FAIL COUNT starts at zero. As its name suggests, the FAIL COUNT parameter represents the RC value per receiver. x The counter indicates the receiver RC x The count of the number of times the keep-alive signal was not detected. After step 24, method 20 continues to step 26.

[0023] In step 26, each receiver RC x An attempt is made to sample the power grid GR to detect the presence of a keep-alive signal. In a preferred embodiment, the sampling period in step 26 is equal to the transmission period of the keep-alive signal, which is within... Figure 3 The example is 75ms. Therefore, step 26 determines whether a keep-alive signal is detected within 75ms, and as previously described, one method of such detection is by using a known 15-bit sequence of the keep-alive signal and comparing it with f M or f S The FSK bit detected at the frequency is correlated in the receiver. Next, method 20 continues from step 26 to step 28.

[0024] In step 28, each receiver RC x It is determined whether the previous decoding operation in step 26 detected a valid keep-alive signal during the monitoring transmission period. If the relevant parameters locate a sufficient peak within the sampling transmission period, thereby indicating such detection, the method flow returns from step 28 to step 24. Therefore, when the receiver detects a single valid keep-alive signal, FAIL COUNT is reset to zero again, and the subsequent decoding steps are repeated. However, if step 28 determines that the decoding step in step 26 failed to detect a valid keep-alive signal during the monitoring transmission period, method 20 continues from step 28 to step 30.

[0025] In step 30, each receiver RC xThe FAIL COUNT parameter is incremented by one. For example, if FAIL COUNT was previously zero, such as in the first instance for steps 26 and 28, then in step 30 below, FAIL COUNT will be equal to one. Thus, as previously described, in the absence of a valid keep-alive signal, the FAIL COUNT parameter continues to hold a count for several consecutive transmission cycles. However, as shown above, when FAIL COUNT is non-zero and a valid keep-alive signal is detected, this event generates the positive lookup in step 28 and causes FAIL COUNT to reset to zero. Instead, each time FAIL COUNT is incremented, step 32 is then performed to determine whether FAIL COUNT exceeds a certain integer threshold THR1, where the value of THR1 can be chosen by those skilled in the art, for example, after empirical testing of system 10. If step 32 determines that FAIL COUNT does not exceed THR1, then method 20 returns from step 32 to step 26, where FAIL COUNT is therefore greater than zero. Conversely, if step 32 determines that FAIL COUNT equals (or exceeds) THR1, then method 20 continues from step 32 to step 34.

[0026] Based on the foregoing, a person skilled in the art should recognize that the receiver RC is only affected by a consecutive number of transmission cycles equal to THR1 (e.g., 75ms intervals). x If no valid keep-alive signal is detected for each such cycle, step 34 is reached. In this case, in step 34, the receiver RC sends a signal to its respective MPPT MP. x Send a signal to disable their respective solar panels SP x The connectivity between the receiver RC and the power grid GR. Therefore, in summary, method 20 represents, in a preferred embodiment, each receiver RC... x The signal is sampled on the grid GR, and if a successive transmission cycle equal to THR1 occurs and the receiver fails to detect a valid keep-alive signal, then the solar panel SP corresponding to that receiver... x Therefore, it is prevented from supplying energy to the grid GR. This understanding leads us back to... Figure 1 Therefore, note that when the expected system 10 is generating power normally and completely, the transmitter 12... T Continuous transmission such as Figure 2 The keep-alive signal is shown, but when safety actuator 12... SA When activated to disconnect power to the grid GR, transmitter 12 T Terminate keep-alive signal transmission; in response, once a number of transmission cycles equal to THR1 have elapsed without a keep-alive signal being transmitted during that entire duration, each MPPT MP xThe signal was sent to block its corresponding solar panel SP x Energy is supplied to the power grid GR. Therefore, the safety actuator 12 is activated in this manner. SA This will promptly and effectively cause a power outage from one or more solar panels to the grid GR for the entire duration of THR1, which is detected for several times the keep-alive signal transmission cycle.

[0027] Another aspect of the preferred embodiment includes a structure and function to reactivate the connection between the solar panel and the power grid GR after the disconnection that occurs from step 34. In this regard, this is achieved through the inverter 12 and its associated transmitter 12. T Control reactivation, such as safety actuator 12 SA These can include additional controls, buttons, interfaces, or events, therefore these property emitters 12 T Activation of any transmitter will restart the transmission of keep-alive signals along the grid GR, and after a sufficient number of these signals are received within a predetermined time period, the energy of the solar panels previously disconnected from the grid GR is rebuilt. In this respect, Figure 5 A preferred embodiment of method 40, consistent with the above description, will now be discussed.

[0028] Figure 5 Explain the RC of each receiver x The flowchart of the preferred embodiment of the operation, method 40, is as follows: Figure 4 Method 20 can be compared in many respects, since it is assumed that the reader is familiar with the previous discussion. Figure 5 This will not be discussed in such detail. In method 40, each receiver RC x Similarly, signals on the grid GR are sampled to detect the presence or absence of keep-alive signal flow. However, in method 40, the presence of an optimally continuous keep-alive signal is detected, and the reactivation of the solar panels SP is achieved. x Appropriate response to the connection between the power grid GR and the grid.

[0029] Method 40 begins with system startup step 42, which is shown in accordance with Figure 4 Method 20: Disconnect the solar panel SP x This is to avoid the startup of system 10 after energy is supplied to the grid GR. Subsequently, in step 44, the corresponding disconnected solar panels SP... x RC receiver x The parameter SUCCESS COUNT will be set to zero. As its name suggests, the parameter SUCCESS COUNT represents the RC value per receiver. x The counter indicates the receiver RC xThe count of the number of times the keep-alive signal was successfully detected. After step 44, method 40 continues to step 46.

[0030] Step 46 and subsequent step 48 are performed and Figure 4 Steps 26 and 28 have the same function. Therefore, in step 46, the receiver RC... x The power grid GR is sampled to detect the presence of a keep-alive signal during the transmission period of the signal, and in step 48, the receiver RC... x It is determined whether a valid keep-alive signal was detected during the monitoring transmission period in the previous decoding step 46. However, in step 48, based on the negative or positive determination of the condition in step 48, the direction of the flow is reversed relative to step 28. In other words, if in step 48 no keep-alive signal was detected in the previous step 46, method 40 returns to step 44 and SUCCESS COUNT is reset to (or maintained at) 0, and decoding step 46 is repeated. However, if step 48 determines that a valid keep-alive signal was indeed detected during the monitoring transmission period in the decoding step 46, method 40 continues from step 48 to step 50.

[0031] In step 50, the receiver RC x Increase its SUCCESS COUNT parameter by 1. Therefore, the SUCCESS COUNT parameter remains within the range corresponding to the receiver RC. x Solar panels SP x The count of several consecutive transmission cycles of the effective keep-alive signal detected after the time of disconnection from the power grid GR. Each time SUCCESS COUNT is incremented in step 50, the next step 52 is executed to determine whether SUCCESS COUNT exceeds a certain integer threshold THR2, wherein the value of THR2 can be selected by a person skilled in the art, for example, after empirical testing of system 10, but preferably, the THR2 in step 52 is greater than that from the time of disconnection from the power grid GR. Figure 4 Step 32 is THR1. If step 52 determines that SUCCESS COUNT does not exceed THR2, then method 40 returns from step 52 to step 46, where SUCCESS COUNT is subsequently greater than 0. Conversely, if step 52 determines that SUCCESS COUNT is equal to (or exceeds) THR2, then method 40 continues from step 52 to step 54.

[0032] Based on the foregoing, a person skilled in the art should recognize that step 54 is only performed by the receiver RC during a consecutive number of transmission cycles equal to THR2 (e.g., 75ms intervals). xSamples are taken and a valid keep-alive signal is detected for each such cycle. In this case, in step 54, the receiver RC... x To their respective MPPT MP x Send signals to enable or reactivate their respective solar panels SP x The connectivity between the solar panel SP and the power grid GR. Therefore, in summary, method 40 illustrates, in a preferred embodiment, the connection between the solar panel SP and the power grid GR. x After being disconnected from the power grid GR, then its corresponding receiver RC x The signal on the power grid GR is sampled, and if a consecutive number of keep-alive signals equal to THR2 are detected, then the corresponding receiver RC... x Solar panels SP x This allows it to be reconnected to supply energy to the grid GR. Therefore, refer back to safety actuator 12. SA Operable to restart sending keep-alive signals along the grid GR after the panel has been disconnected from the grid, so that method 40 will reconnect the solar panel to supply energy to the grid GR after receiving a sufficient number of these signals within a predetermined time period, where the connection was previously disconnected.

[0033] Figure 6 This instruction is used to detect keep-alive signals and enable or disable solar panel SPs. x Alternative preferred embodiments of the method for connectivity to the power grid GR, namely respectively as Figure 4 and Figure 5 Alternatives to methods 20 and 40. However, as a brief overview, methods 20 and 40 operate in response to each consecutive keep-alive signal transmission cycle, and control can be altered based on a single keep-alive signal (e.g., received in step 26 or not received in step 46), while method 60 performs most of the decoding process over an odd number of Z keep-alive signal transmission cycles, wherein during the Z time period, most of the detection signals or their absence causes the solar panel SP to be de-energized relative to the grid GR. x Synthesis control for connection or disconnection. The following describes an example of the specific steps to implement this functionality.

[0034] Method 60 begins at system initiation step 62, illustrating the initial default state of system 10, which can be set up such that all solar panels are connected (via their respective MPPTs) to the grid GR, or alternatively, for a safety mode, it can be such that all solar panels are disconnected from the grid GR. Next, in step 64, the enable parameter Z for each receiver is reset to 0, and method 60 continues to step 66. In step 66, in the same manner described previously for step 26 (or step 46), each receiver RCx attempts to sample the grid GR to detect the presence of a keep-alive signal. Subsequently, in step 68, the enable parameter Z is incremented, after which method 60 continues to step 70.

[0035] Step 70 is a conditional step so that overall method 60 will analyze the total number of sampling periods (i.e., transmission periods) equal to an odd value denoted as THR3. Therefore, step 70 determines whether step 66 has been repeated a total of THR3 times, wherein if the total number has not been reached, method 60 loops backward to decode another transmission period and increments the index Z again, and once the total number THR3 is reached, method 60 continues to step 72.

[0036] In step 72, each receiver RC x Perform majority decoding on the 3 THR sampling periods that have already been decoded in step 66 to determine whether a valid keep-alive signal has been detected in a majority of these periods. In other words, since THR3 is odd, step 72 determines whether a majority of the 3 THR transmission periods are occupied by a valid keep-alive signal. For example, if THR3 is 9 periods, step 72 determines whether a valid keep-alive signal exists in at least 5 of these periods (i.e., ROUNDUP(THR3 / 2) = ROUNDUP(9 / 2) = 5). If a valid keep-alive signal is detected in a majority of the 3 THR periods, method 60 proceeds to step 74, which is similar to... Figure 5 Step 54 in the process controls MPPT MP x To enable the corresponding solar panel SP x Connectivity to the power grid GR. Conversely, if a valid keep-alive signal is not detected for most of the three THR cycles, method 60 proceeds to step 76, which is similar to... Figure 4 Step 44 in the process controls MPPT MP x To disable the corresponding solar panel SP xFrom the grid GR connectivity. After step 74 or step 76, method 60 continues to step 78, which provides an additional fail-safe assessment. Specifically, step 78 determines whether the multiple alternating on / off transitions from steps 74 and 76 have occurred within a certain time period threshold; if this has occurred, such transitions may be of concern, and as a result, method 60 continues from step 78 to step 80, which is similar to step 76 disabling the corresponding solar panel SP due to fairly frequent on / off transitions (one of which a person skilled in the art can choose an appropriate number and time period threshold for step 78). x From the connectivity of the power grid GR. Conversely, if this repeated transition is not detected in step 78, method 60 returns to step 64, so that the next set of THR3 transmission cycles can be analyzed in a manner comparable to that described above.

[0037] For method 60, a person skilled in the art may choose to give a trade-off value for Z, because the larger the value of Z, the longer the amount of time required before reaching step 72; that is, the larger the value of Z, the longer the time required for the safety actuator 12. SA The greater the amount of time elapsed between the actuation and the response action of step 74 or 76, the better. Specifically, this amount of time is at least equal to Z times the keep-alive signal transmission period (e.g., 75 ms). According to a preferred embodiment, therefore, Z equals seven or nine, because tests have shown that the error generated for these numbers should be sufficient. Specifically, this test takes into account potential errors in operation, such as those occurring after the solar panel SP stops transmitting the keep-alive signal. x The first error that unexpectedly keeps the connection connected, or such as when not a sufficient number of keep-alive signals are transmitted to the solar panel SP. x The second error was also reconnected to the grid GR. However, it should be considered that the probability of predicting such an error for Z=9 was only one percent over the centuries of operation (if not longer).

[0038] The above describes the RC of each receiver. x How to respond to the same single 15-bit code (e.g., Figure 3 To encourage their respective solar panels SP x The connection or disconnection to the power grid GR, however, recalls the previously mentioned alternative preferred embodiments that provide control over the group of solar panels. In this regard, Figure 7 Explain alternative messaging protocols to maintain connectivity between the solar panels and the grid GR, transmitter 12 T again along Figure 1 The wired connection transmits a continuous stream of keep-alive signals, but in Figure 7In this context, the stream comprises a group of S 15-bit keep-alive signals, wherein each of the S signals in the group preferably has the same transmission duration (e.g., 75 ms, again), but its binary value differs from the other signals in the group, preferably selected from a set of pseudo-orthogonal signals, and wherein each of these signals is used to control a separate set of one or more MPPTs (and their corresponding solar panel grid connectivity). For example, assuming S = 4, then... Figure 7 This aims to illustrate the first keep-alive signal KAS in the first transmission cycle of S transmission cycles. 1.1 Transmitted, second keep-alive signal KAS 1.2 The sequence of S keep-alive signals is followed by a continuous phase change, with the third to the Sth (i.e., the fourth) keep-alive signal being followed by a total duration of S multiplied by the transmission time period of each individual keep-alive signal (i.e., 4 * 75 ms = 300 ms). Thereafter, the entire sequence of S keep-alive signals is retransmitted whenever connectivity between the solar panel cluster and the grid GR is desired.

[0039] Considering Figure 7 The sequence, alternative preferred embodiments modified. Figure 4 , Figure 5 and Figure 6 Any one of them, so that each receiver performs its decoding step only with respect to the 15-bit sequence assigned to that particular receiver. For example, suppose system 10 includes a total of eight solar panels SP1 to SP8, wherein the solar panels are paired with respect to a control keep-alive signal, so, as an example, panels SP1 and SP2 and their respective receivers RC1 and RC2 respond to the first keep-alive signal KAS 1.1 Meanwhile, panels SP3 and SP4 and their respective receivers RC3 and RC4 respond to the second keep-alive signal KAS. 1.2 And so on, as shown in Table 1 below:

[0040]

[0041]

[0042] Table 1

[0043] Considering the control signals shown in Table 1, each receiver RC within a duration equal to S multiplied by the duration of a single signal transmission period (e.g., 300 ms) xPerform its decoding steps (i.e., steps 26, 46, or 66) to determine whether its individual 75ms signal is detected during the same time period. Because the preferred embodiment implements a pseudo-orthogonal bit sequence in a set of S keep-alive signals, satisfactory correlation detection should be provided for each of the different signals. In addition to this variation, any of methods 20, 40, or 60 can be followed to apply the remaining steps regarding the receiver and its corresponding keep-alive signal. For example, in the example in Table 1, if method 60 is performed, the receiver RC1 will attempt to locate the keep-alive message KAS during the first 300ms interval. 1.1 After that, the Z index increases and the process is repeated until three such 300ms intervals of THR are sampled; then, if most of the decoded keep-alive messages KAS are valid during the Z sampling periods... 1.1 Then receiver RC1 will control MPPT MP1 to connect solar panel SP1 to the grid GR, or if most of the samples in the Z sampling period fail to locate a valid keep-alive signal KAS during that interval. 1.1 Then, receiver RC1 will control MPPT MP1 to disconnect solar panel SP1 from the grid GR. Simultaneously, during the same time interval, other receivers will operate similarly regarding their respective keep-alive signals. For example, when executing method 60 in the same way, receiver RC8 will attempt to locate the keep-alive message KAS during the same first 300ms interval. 1.4 During the first 300ms interval, receiver RC1 responds to the keep-alive message KAS 1.1 Sampling is performed, followed by incrementing the Z index and repeating this process until three such 300ms intervals (THR3) are sampled; subsequently, if the majority of the decoded keep-alive messages (KAS) are valid for the majority of the Z sampling periods within that interval, then... 1.4 Then the receiver RC8 will control MPPT MP8 to connect the solar panel SP8 to the grid GR, or if a valid keep-alive signal KAS is not located for most of the Z sampling periods in that period. 1.4 Then, receiver RC8 will control MPPT MP8 to disconnect solar panel SP8 from the grid GR. When implementing any of methods 20, 40, or 60, a person skilled in the art should readily recognize the comparable operation of the remaining receivers and their respective MMPTs / panels.

[0044] Considering the foregoing, preferred embodiments provide an improved PV (solar panel) system operable to disconnect or reactivate such panel connectivity to the power grid, for example, in conjunction with safety considerations. While various aspects have been described, substitutions, modifications, or alterations can be made to the above description without departing from the scope of the invention. For example, although each solar panel / MPPT pair in system 10 includes a receiver, in an alternative preferred embodiment, a single receiver may be used to control multiple MPPTs and the connectivity of the solar panel to these MPPTs. As another example, although the messaging protocol is shown as providing bits for enabling solar panel connectivity to the grid, such bits, or an alternative set of bits, may also be used to provide additional commands. As yet another example, although method 60 is described in conjunction with a sampling continuum of Z multiplied by the keep-alive signal transmission period, in an alternative preferred embodiment, a sliding time window may be used so that most recent THR3 sampling periods are analyzed in conjunction with most decoding decisions. As yet another example, the various flowchart steps can be reordered or further modified (including adding additional steps), and the magnitudes of the parameters can be adjusted, such as changing the signal bit size, transmission period, THR1, THR2, THR3, N, Z, etc. A person skilled in the art will recognize that there are other examples, and these examples are not intended to limit the scope of the invention; rather, the scope of the invention is defined by the appended claims.

Claims

1. A system for a solar panel, the system comprising: power supply; A switching circuit, comprising: A set of inputs coupled to the power supply; A set of outputs operable to be coupled to a DC power grid, such that the power supply is coupled to the DC power grid via the switching circuit; and Control input; and A receiver operable to be coupled in parallel with the switching circuit to the DC power grid, wherein: The receiver includes a counter and a control output coupled to the control input of the switching circuit; and The receiver is operable to: Monitor the signals on the DC power grid; In response to the signal, the counter is incremented; In response to the absence of the signal, the counter is reset; and The switching circuit responds to the count of the counter to couple and decouple the power supply from the DC power grid.

2. The system according to claim 1, wherein the signal is included in the message protocol of frequency shift keying modulation, i.e., the message protocol of FSK modulation.

3. The system of claim 1, wherein the signal is encoded into a bit sequence.

4. The system according to claim 3, wherein: The signal is the first signal; The bit sequence is the first bit sequence; The receiver is operable to increment the counter in response to the first signal encoded as the first bit sequence; and The receiver is operable to ignore a second signal on the DC power grid, the second signal being encoded as a second bit sequence different from the first bit sequence.

5. The system according to claim 4, wherein the first bit sequence and the second bit sequence are pseudo-orthogonal.

6. The system of claim 4, wherein the first signal and the second signal are transmitted without a time interval between the first signal and the second signal.

7. The system of claim 1, further comprising a transmitter operable to couple to the DC power grid and provide the signal through the DC power grid.

8. The system of claim 7, further comprising an inverter, the inverter comprising: A set of inputs operable to be coupled in parallel with the transmitter to the DC power grid; A set of outputs operable to be coupled to an AC power grid; and An inverter circuit that is operable to use power from the DC power grid to provide power on the AC power grid.

9. The system of claim 1, further comprising a DC-DC converter operable to convert a first DC voltage of the power source into a second DC voltage of the DC power grid.

10. The system of claim 1, wherein the receiver is further operable to: Detect the number of times the switching circuit performs coupling and decoupling between the power supply and the DC power grid within a time period; and The switching circuit decouples the power supply from the DC power grid in response to the number of switching cycles.

11. An apparatus for a solar panel, the apparatus comprising: A switching circuit operable to couple a power source to a DC power grid, wherein the switching circuit includes a control input; and A receiver operable to be coupled in parallel with the switching circuit to the DC power grid, wherein: The receiver includes a counter and a control output coupled to the control input of the switching circuit; and The receiver is operable to: Monitor the signals on the DC power grid; In response to failure to receive the signal, the counter is incremented; In response to receiving the signal, the counter is reset; and In response to the counter exceeding a threshold, the switching circuit decouples the power supply from the DC power grid.

12. The device of claim 11, further comprising the power supply.

13. The device according to claim 11, further comprising: A transmitter operable to couple to and provide the signal through the DC power grid; and Inverter, which can be operated as: It is coupled in parallel to the DC power grid with the transmitter; Coupled to the AC power grid; and Power is supplied from the AC power grid using power from the DC power grid.

14. The apparatus of claim 11, wherein the signal is contained in a frequency shift keying modulation message protocol, i.e., an FSK modulation message protocol, and is encoded as a bit sequence.

15. The device according to claim 14, wherein: The signal is the first signal; The bit sequence is the first bit sequence; The receiver is operable to increment the counter in response to failure to receive the first signal encoded as the first bit sequence; and The receiver is operable to ignore a second signal on the DC power grid, the second signal being encoded as a second bit sequence different from the first bit sequence.

16. An apparatus for a solar panel, the apparatus comprising: A switching circuit operable to couple a power source to a DC power grid, wherein the switching circuit includes a control input; and A receiver operable to be coupled in parallel with the switching circuit to the DC power grid, wherein: The receiver includes a counter and a control output coupled to the control input of the switching circuit; and The receiver is operable to: Monitor the signals on the DC power grid; In response to receiving the signal, the counter is incremented; In response to failure to receive the signal, the counter is reset; and In response to the counter exceeding a threshold, the switching circuit couples the power supply to the DC power grid.

17. The device of claim 16, further comprising the power supply.

18. The apparatus of claim 16, further comprising: A transmitter operable to couple to and provide the signal through the DC power grid; and Inverter, which can be operated as: It is coupled in parallel to the DC power grid with the transmitter; Coupled to the AC power grid; and Power is supplied from the AC power grid using power from the DC power grid.

19. The apparatus of claim 16, wherein the signal is contained in a frequency shift keying modulation message protocol, i.e., an FSK modulation message protocol, and is encoded as a bit sequence.

20. The apparatus according to claim 19, wherein: The signal is the first signal; The bit sequence is the first bit sequence; The receiver is operable to increment the counter in response to receiving the first signal encoded as the first bit sequence; and The receiver is operable to ignore a second signal on the DC power grid, the second signal being encoded as a second bit sequence different from the first bit sequence.

Images