# US 12,113,476 B2 · System and method for configuring an array of solar panels to be safe for human contact > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,113,476 B2 - Document ID: US12113476B2 - Status: Granted - Kind: B2 - Application number: 16/501,400 - Filed: 2017-10-10 - Published: 2022-05-12 - Granted: 2024-10-08 - Earliest claimed: 2016-10-07 - Applicants: Kent Kernahan - Inventors: Kent Kernahan - Web page: https://patentgrep.com/patent/US12113476B2 ## CPC - H02S 40/32: comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules - H02S 50/00: Monitoring or testing of PV systems, e.g. load balancing or fault identification - G01R 31/66: Testing of connections, e.g. of plugs or non-disconnectable joints (testing for incorrect line connections G01R31/55) - H02S 40/36: characterised by special electrical interconnection means between two or more PV modules, e.g. electrical module-to-module connection - H02S 50/10: Testing of PV devices, e.g. of PV modules or single PV cells (testing of semiconductor devices during manufacturing {H10P74/00}) - Y02E 10/50: Photovoltaic [PV] energy - H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A system comprising an array of solar panels, each panel including an electronic control module, wherein the panels are all connected in electrical series with each other and to a switch and to a string inverter, may be signaled to power down each panel to a safe output at its output terminals. The method includes sensing output wave forms of a module to be the result of its own DC-DC converter output or to be at variance with the expected output. Output wave forms at variance indicate that the control module is connected in electrical series with the input capacitance of the string inverter. If the output is as expected, the control module is deemed to not be connected to the capacitance of the string inverter as a result of the electrical series switch being open. The module then immediately drives its output to a safe level. ## Claims ### Claim 1 An apparatus comprising: a) a DC-DC converter having a DC-DC converter input terminal and a DC-DC converter output terminal; b) a processor having a processor input terminal and a processor output terminal, wherein the processor output terminal is operatively connected to the DC-DC converter input terminal, the processor further including program memory to perform the steps of: i) comparing a DC-DC converter output AC ripple voltage to an expected output AC ripple voltage for the DC-DC converter not electrically connected to a capacitive load from a string inverter; and ii) when the DC-DC converter output AC ripple voltage does not match the expected output AC ripple voltage, continuing a high power output from the DC-DC converter, otherwise driving the DC-DC converter to a safe output voltage; and c) an analog to digital converter having an analog to digital converter input terminal and an analog to digital converter output terminal, the analog to digital converter input terminal is connected to the DC-DC converter output terminal, the analog to digital converter output terminal is connected to the processor input terminal, and the analog to digital converter provides to the processor a digital representation of an output voltage from the DC-DC converter including the DC-DC converter output AC ripple voltage. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the analog to digital converter is integrated within the processor. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the safe output voltage is compliant with standard NEC 2014 690.12. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the safe output voltage is less than 30 volts. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the step of comparing the DC-DC converter output AC ripple voltage to the expected output AC ripple voltage includes comparing time periods between AC ripple peaks. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the step of comparing the DC-DC converter output AC ripple voltage to the expected output AC ripple voltage includes comparing time periods between synch pulses and AC ripple peaks. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the program memory further performs the step of optionally repeating step i) while the DC-DC converter has the safe output voltage. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the program memory further performs the step of optionally driving the DC-DC converter to output a voltage compliant with the standard NEC 2014 690.12. ### Claim 9 In a solar panel system comprising a plurality of solar panels each having an input terminal and an output terminal electrically connected in series with a string inverter, the improvement comprising at least one solar panel comprising: a) a DC-DC converter having a DC-DC converter input terminal electrically connected to the output terminal of the at least one solar panel and a DC-DC converter output terminal; b) a processor having a processor input terminal and a processor output terminal, wherein the processor output terminal is operatively connected to the DC-DC converter input terminal; the processor further including program memory to perform the steps of: i) comparing a DC-DC converter output AC ripple voltage to an expected output AC ripple voltage for the DC-DC converter not electrically connected to a capacitive load from the string inverter; and ii) when the DC-DC converter output AC ripple voltage does not match the expected output AC ripple voltage, continuing high power output from the DC-DC converter, otherwise driving the DC-DC converter to a safe output voltage; and c) an analog to digital converter having an analog to digital converter input terminal and an analog to digital converter output terminal, the analog to digital converter input terminal is connected to the DC-DC converter output terminal, the analog to digital converter output terminal is connected to the processor input terminal, and the analog to digital converter provides to the processor a digital representation of an output voltage from the DC-DC converter including the DC-DC converter output AC ripple voltage. ### Claim 10 (depends on 9) The solar panel system of claim 9, wherein the analog to digital converter is integrated within the processor. ### Claim 11 (depends on 9) The solar panel system of claim 9, wherein the safe output voltage is compliant with the standard NEC 2014 690.12. ### Claim 12 (depends on 9) The solar panel system of claim 9, wherein the safe output voltage is less than 30 volts. ### Claim 13 (depends on 9) The solar panel system of claim 9, wherein said at least one solar panel is all the solar panels in the solar panel system. ### Claim 14 (depends on 9) The solar panel system of claim 9, wherein the step of comparing the DC-DC converter output AC ripple voltage to the expected output AC ripple voltage includes comparing time periods between AC ripple peaks. ### Claim 15 (depends on 9) The solar panel system of claim 9, wherein the step of comparing the DC-DC converter output AC ripple voltage to the expected output AC ripple voltage includes comparing time periods between synch pulses and AC ripple peaks. ### Claim 16 (depends on 9) The solar panel system of claim 9, wherein the program memory further performs the step of optionally repeating step i) while the DC-DC converter has the safe output voltage. ### Claim 17 (depends on 16) The solar panel system of claim 16, wherein the program memory further performs the step of optionally driving the DC-DC converter to output voltage not greater than thirty volts per the standard NEC 2014 690.12. ### Claim 18 In a solar panel system comprising a plurality of solar panels each having an input terminal and an output terminal electrically connected in series with a string inverter, the improvement comprising at least one solar panel comprising: a) a DC-DC converter having an input terminal and an output terminal; b) a processor having an input terminal and an output terminal, wherein the processor output terminal is operatively connected to the DC-DC converter input terminal; the processor further including program memory to perform the steps of: i) comparing a DC-DC converter output AC ripple voltage to a predetermined output AC ripple voltage; and ii) optionally driving the DC-DC converter to a safe output voltage; c) an analog to digital converter having an input terminal and an output terminal, the analog to digital converter input terminal is connected to the output terminal of the DC-DC converter, the analog to digital converter output terminal is connected to the input terminal of the processor, and the analog to digital converter provides to the processor a digital representation of an output voltage from the DC-DC converter; and the safe output voltage is less than 30 volts and is attained within less than one second after opening a disconnect switch. ### Claim 19 An apparatus, comprising: a) a DC-DC converter having an input terminal and an output terminal; b) a processor having an input terminal and an output terminal, wherein the processor output terminal is operatively connected to the DC-DC converter input terminal, the processor further including program memory to perform the steps of: i) comparing a DC-DC converter output AC ripple voltage to an expected output AC ripple voltage; and ii) driving the DC-DC converter to a safe output voltage; c) an analog to digital converter having an input terminal and an output terminal, the analog to digital converter input terminal is connected to the output terminal of the DC-DC converter, the analog to digital converter output terminal is connected to the input terminal of the processor, and the analog to digital converter provides to the processor a digital representation of an output voltage from the DC-DC converter; and the safe output voltage is less than 30 volts and is attained within less than one second after a disconnect switch electrically in series with the DC-DC converter output terminal and a string inverter is opened.