A Segmented Cell Measuring Technique for Current Distribution Measurements in Batteries, Exemplified by the Operando Investigation of a Zn-Air Battery

A transimpedance amplifier circuit as well as an instrumental amplifier circuit were used to measure current densities of a zinc-air battery with an integrated segmented current collector foil. Error calculation showed that the transimpedance amplifier is superior to the used instrumental amplifier, but both methods provide valuable and consistent results. They both showed comparable results with operando insight into the current distribution of the battery. The knowledge about those distributions is essential to avoid fast degradation of battery materials and irreversible capacity loss due to heterogeneous dissolution of the anode during discharge. In this work we showed that oxygen starvation as well as gas flow rate leads to large current gradients. It was also demonstrated that heterogeneous current distributions on cathode side induces also a heterogenous dissolution behavior on the anode, resulting in irreversible capacity loss.

A bridgeless CUK PFC converter with positive output voltage

The output voltage of the traditional CUK PFC converter is negative, and an additional inverting amplifier circuit is needed, which increases the volume and cost of the converter. A new type of bridgeless CUK PFC converter topology is proposed in this paper, which makes the converter have a positive output voltage without the need of an additional inverting amplifier circuit, and has the advantages of simple control, high efficiency, and low cost. Through topology optimization, one input capacitor is reduced, and the two diodes are converted from the high-current working state of high frequency to low-current working state of power frequency, ordinary rectifier diodes can be selected instead of fast recovery diodes, thereby reducing the volume and cost of the converter. The converter works in DCM, so no current control loop is required, which simplifies the control circuit. In addition, the main switch is turned on under ZVS condition, and the output diode is turned off under ZCS condition, which reduces the switching loss and improves the efficiency of the converter. A simulation model was built in PSIM, and a prototype with a rated power of 150 W was fabricated to verify the effectiveness and superiority of the proposed converter. Experimental results show that the PF of the proposed converter is 0.995 7, and the input current THD is 3.78% under rated input conditions.

Performance Improvement of Spaceborne Carbon Dioxide Detection IPDA LIDAR Using Optimization of Optical Detector and Amplifier Linearity

The spaceborne double-pulse integrated-path differential absorption (IPDA) light detection and ranging (LIDAR) system was found to be helpful in observing atmospheric CO2 and understanding the carbon cycle. The airborne experiments of a scale prototype of China’s planned spaceborne IPDA LIDAR was implemented in 2019. A problem with data inversion caused by the detector module nonlinearity was found. Through many experiments, the amplifier circuit board (ACB) of the detector module was proved to be the main factor causing the nonlinearity. Through amplifier circuit optimization, the original bandwidth of the ACB was changed to 1 MHz by using a fifth-order active filter. Compared with the original version, the linearity of optimized ACB is improved from 42.6% to 0.0747%. The optimized ACB was produced and its linearity was verified by experiments. In addition, the output waveform of the optimized ACB changes significantly, which will affect the random error (RE) of the optimized IPDA LIDAR system. Through the performance simulation, the RE of more than 90% of the global area is less than 0.728 ppm. Finally, the transfer model of the detector module was given, which will be helpful for the further optimization of the CO2 column-averaged dry-air mixing ratio (XCO2) inversion algorithm.

Uncertainty and sensitivity analysis applied to a voltage series operational amplifier

This paper investigates the applied uncertainty and sensitivity analysis to resistors used in voltage series operational amplifier circuit. Two resistors bands are considered which are the gold band (5% uncertainty) and the silver band (10% uncertainty). To generate resistors uncertainty sample points, the SIMLAB uncertainty and sensitivity tool is used. A total of sample points based on Sobol’ technique has been created for each resistor band. The voltage series amplifier is modelled in MATLAB/Simulink. A MATLAB script has been written to execute Monte-Carlo simulations for reading the resistor sample points, updating and executing the voltage series model and finally calculating the voltage gain. The result of uncertainty analysis shows that the produced voltage gain is uncertain within the range of for the gold band and for the silver band with respect to a reference voltage gain. The result of sensitivity analysis shows that each resistor, although their values are different, contributes equally contribution to the uncertainty of voltage gain.