Method and apparatus for in-situ health monitoring of solar cells in space

An apparatus for in-situ monitoring of solar cells, comprising:

• an oscillator operatively connected to a first set of switches and a second set of switches, and to that outputs a waveform with a low time and a high time;
• an inverter operatively connected to the oscillator, and that inverts the waveform received from the oscillator;
• a ramp generator operatively connected to the oscillator, and that increases a gate control voltage of a first transistor and then rapidly decreases the gate control voltage of the first transistor;
• and
• a solar cell string comprising a first node operatively connected to a drain of the first transistor, and a second node operatively connected to a source of the first transistor via a first resistor,
• wherein, when the ramp generator increases the gate control voltage of the first transistor, the solar cell string is subjected to a decreasing resistance of the first transistor to monitor a voltage and a current of the solar cell string.

A method for in-situ monitoring of solar cells, comprising:

• generating a waveform comprising a low time and a high time;
• receiving the waveform from an oscillator, and inverting the waveform;
• increasing a gate control voltage of a transistor connected to a solar cell, and then rapidly decreasing the gate control voltage of the transistor;
• measuring, during the low time of the waveform, a current and a voltage of the solar cell as the current and voltage of the solar cell are transmitted through a first channel and to a second channel;
• and
• measuring, during the high time of the waveform, a current of a shorted cell and a voltage reference as the current of the shorted cell and the voltage reference are transmitted through the first channel and the second channel.

A method for in-situ monitoring of solar cells, comprising:

• outputting a waveform with a low time and a high time;
• inverting the waveform received from an oscillator;
• increasing a gate control voltage of a first transistor, and then decreasing the gate control voltage of the first transistor;
• and
• subjecting a solar cell string to a decreasing resistance and monitoring a voltage and a current of the solar cell string by increasing the gate control voltage of the first transistor, which is connected to the solar cell string.

An apparatus for in-situ monitoring of solar cells configured to measure a plurality of measurement variables on two channels, the apparatus comprising:

• a clock generator that generates a waveform operating at a frequency of one cycle per second;
• a ramp generator that increases a gate control voltage on a transistor connected to a solar cell and decrease the gate control voltage connected to the transistor;
• and
• a switch that allows the ramp generator to increase the gate control voltage of the transistor, and to that allows current and voltage measurements on the two channels, during a long period of the cycle,
• wherein the switch is further configured to allow the ramp generator to decrease the gate control voltage, and to allow a current of a shorted cell and a voltage reference to be measured on the two channels, during a short period of the cycle.