Unsa ang praktikal nga paggamit sa mga transformers sa power electronics?

1. Prinsip Pagsulob sa Spark Gap

Ang spark gap nagoperahan batas sa prinsipyo sa gas discharge. Kapag ang sapat na mataas nga voltaje gitugotan tali sa duha ka elektrodo, ang gas sa pagitan sa mga elektrodo gipasabog, ug naghimo og conductive channel, ug kini resulta sa spark discharge. Kini parehas sa discharge phenomenon nga mahitabo tali sa mga ulan ug yuta panahon sa lightning. Ang pasabog sa gas kay tungod kay ang kalakipan sa electric field kay sapat sa pagsala sa elektron sa gas molecules para makakuha og sapat nga enerhiya aron mawala sa bondage sa atom o molekula, ug naghimo og free electrons ug ions. Kini nga mga free electrons ug ions mag-accelerate sa pagtumong sa electric field, mogapit sa uban pang gas molecules, umani og mas daghan pa nga ionization processes, ug hukom nahimong breakdown sa gas ug formation sa spark discharge.

Batason sa Paschen's law, ang breakdown voltage sa gas usa ka function sa gas pressure, electrode spacing, ug tipo sa gas. Ug tubagon ang isyu nga espesipiko nga tipo sa gas ug pressure, adunay sigurado nga relasyon tali sa electrode spacing ug breakdown voltage. Sa general, ang mas dako nga electrode spacing, mas taas ang breakdown voltage.

2. Basic Methods of Using the Spark Gap to Determine the Voltage

Calibrating the Spark Gap Device

Unsa man, kinahanglan nga calibrate ang spark gap gamiton ang nailhan nga voltaje. Usa ka standard voltage source, sama sa high-precision DC o AC voltage generator, mahimong gamiton ug ikonekta sa electrodes sa spark gap. Gradually increase the voltage until spark generation is observed, and record the voltage value and the corresponding electrode spacing at this time. For example, for a spark gap with air as the medium, when the electrode spacing is 1 mm, the breakdown voltage measured using the standard voltage source is 3 kV, thus obtaining a calibration data point.

By changing the electrode spacing and repeating the above process, a series of breakdown voltage data corresponding to different electrode spacings can be obtained, and the relationship curve between electrode spacing and breakdown voltage can be plotted. This provides a calibration basis for the subsequent measurement of an unknown voltage.

Measuring the Unknown Voltage

When determining an unknown voltage, connect the unknown voltage source to the calibrated spark gap device. Gradually increase the voltage until spark discharge is observed. Measure the electrode spacing at this time, and then according to the previously plotted calibration curve, look up the corresponding voltage value. This voltage value is approximately the unknown voltage. For example, when measuring the voltage of a high-voltage pulse, if spark generation is observed when the electrode spacing is 2 mm, and the corresponding voltage obtained from the calibration curve is 6 kV, then the voltage of the high-voltage pulse is determined to be approximately 6 kV.

3. Precautions and Sources of Error

Influence of Gas Conditions: The type, pressure, and humidity of the gas can have a significant impact on the breakdown voltage. For example, in a high-humidity environment, the increase in water vapor content in the air will lower the breakdown voltage of the gas. Therefore, during the measurement process, it is necessary to keep the gas conditions as stable as possible. If possible, it is best to conduct the measurement under standard atmospheric pressure and in a dry environment, or make corrections for changes in gas conditions.

Influence of Electrode Shape and Surface Condition: The shape (such as spherical, needle-shaped, flat-plate-shaped, etc.) and surface condition (such as roughness, presence of oxide layers, etc.) of the electrodes will also affect the breakdown voltage of the spark gap. Different shapes of electrodes will result in an uneven electric field distribution, thereby changing the breakdown voltage. For example, the needle-plate electrode structure has an electric field concentrated at the tip of the needle electrode, making it more prone to breakdown, and its breakdown voltage is relatively low. The roughness and oxide layers on the electrode surface may adsorb gas molecules or change the electric field distribution. Therefore, during the measurement process, it is necessary to ensure the consistency of electrode shape and surface condition, or take these factors into account and make corrections.

 Limitations of Measurement Precision: Measuring voltage using a spark gap is a relatively rough method, and its precision is limited by multiple factors. Besides the above-mentioned gas conditions and electrode factors, spark discharge itself is an instantaneous and somewhat random process that is difficult to precisely control and measure. Moreover, in high-voltage situations, multiple discharges or continuous arcs may occur, which will also affect the accuracy of the measurement results. Therefore, this method is usually used for a rough estimate of the voltage rather than for high-precision voltage measurement.