Abstract: A method for evaluating performance of a natural gas analysis system includes obtaining components of a natural gas analysis system as well as the maximum allowable error and the maximum allowable deviation of a calorific value of each of the components. The method includes determining components and uncertainties of a standard gas mixture; obtaining a final peak area of each of the components in each group of standard gas mixture. The method includes obtaining calibration functions of the natural gas analysis system and analytical functions of respective components. The method includes obtaining an uncertainty and a calorific value uncertainty of each of the components. The method includes judging whether the evaluation result from the natural gas analysis system to be evaluated is qualified, and providing a performance evaluation conclusion for the natural gas analysis system.

Abstract: A method for monitoring impedance of an electrolyzer, a controller and a power supply system are provided. In the method, according to a basic electric energy command, a power supply connected with the electrolyzer is controlled to output a DC component signal used for normal operation of the electrolyzer, and according to an impedance scanning electric energy command, the power supply is controlled to output AC component signals used to monitor the impedance of the electrolyzer. Further, a voltage vector and a current vector outputted by the power supply are acquired, and an impedance value of the electrolyzer is calculated according to the voltage vector and the current vector.