A Wide Input Auxiliary Power Supply with Adaptive Switching Winding

Abstract

The invention provides a wide-input auxiliary power supply with self-adaptive switching windings, which is equipped with a high-frequency transformer, a switch control circuit, an input winding selection circuit, a voltage detection circuit and a hysteresis comparison circuit, and the input terminal of the high-frequency transformer is a double winding , the output end is a single winding, and the same-name end of the input end winding is respectively connected to the positive pole of the output end of the photovoltaic array and the positive pole of the DC bus side; the switch control circuit includes a corresponding switch tube, pulse modulator and drive circuit of the winding; the winding of the input end The selection circuit includes a relay, an error amplifier, and the winding switching signal is input to the control terminal of the relay to realize switching and selection of the winding. The voltage detection circuit obtains the DC bus voltage by means of resistor division, and inputs it to the hysteresis comparison circuit through a photocoupler; The hysteresis comparison circuit generates a winding switching signal for the input winding by comparing the output signal of the voltage detection circuit with the hysteresis reference signal.

Description

technical field [0001] The invention belongs to the technical field of auxiliary power supplies for photovoltaic inverters, and in particular relates to a wide-input auxiliary power supply for adaptively switching windings. Background technique [0002] In the two-stage photovoltaic grid-connected inverter, due to the need to consider the island effect, the auxiliary power supply must be separated from the grid, so its energy must come directly or indirectly from the photovoltaic array. However, the output voltage range of the photovoltaic array is wide and does not Stable, so the design of the auxiliary power supply is more difficult. If the power is taken directly from the photovoltaic array, it is difficult to meet the requirements of the general power supply due to the wide range of output voltage of the photovoltaic array; Low, the auxiliary power supply cannot work normally or the output voltage of the auxiliary power supply is unstable, which affects the safety of th...

AI Technical Summary

Problems solved by technology

[0002] In the two-stage photovoltaic grid-connected inverter, due to the need to consider the island effect, the auxiliary power supply must be separated from the grid, so its energy must come directly or indirectly from the photovoltaic array. However, the output voltage range of the photovoltaic array is wide and does not Stable, so the design of the auxiliary power supply is more difficult

If the power is taken directly from the photovoltaic array, it is difficult to meet the requirements of the general power supply due to the wide range of output voltage of the photovoltaic array; Low, the auxiliary power supply cannot work normally or the output voltage of the auxiliary power supply is unstable, which affects the safety of the system, and the auxiliary power supply needs to have a high starting voltage to take power from the bus side, which makes, when the output voltage of the photovoltaic array is low, The system does not work, wasting the electricity generated by the photovoltaic array at low power

When the system is about to shut down, the entire system will be powered off at the same time, which cannot guarantee that the system will exit work safely and reliably

Images