How to avoid the magnetic saturation transient effect of distribution transformer
Note that the flux should be checked for saturation near the minimum input voltage and maximum pulse width. Since the pulse width is narrowed when the input voltage is high, the core is far from saturation. At transient loads, when the input voltage is high and the load current is small, if the load current suddenly increases, the control circuit immediately increases the pulse width to provide supplemental power. In this way, both the input voltage and the pulse width become maximum at the same time, and even for a short period of time, the distribution transformer will be saturated and cause loss of control and malfunction. Here are a few ways to avoid getting out of control.
(1) The transformer is designed with high input, voltage and wide pulse to make the core work at low magnetic flux density and wind more primary windings. The disadvantage of this method is to reduce the efficiency of the transformer and increase the volumetric weight of the transformer.
(2) The control circuit should work in a highly sensitive state. When the high input voltage occurs, the pulse width can be quickly limited so that it is still at a safe value.
(3) Improve performance on the control circuit so that the switch tube can quickly react to control during the current duty cycle. The UC1846/UC1847 current mode control chip automatically implements this limiting action.
ZTELEC, China professional distribution transformer manufacturer
(1) The transformer is designed with high input, voltage and wide pulse to make the core work at low magnetic flux density and wind more primary windings. The disadvantage of this method is to reduce the efficiency of the transformer and increase the volumetric weight of the transformer.
(2) The control circuit should work in a highly sensitive state. When the high input voltage occurs, the pulse width can be quickly limited so that it is still at a safe value.
(3) Improve performance on the control circuit so that the switch tube can quickly react to control during the current duty cycle. The UC1846/UC1847 current mode control chip automatically implements this limiting action.
ZTELEC, China professional distribution transformer manufacturer