Maximum power tracking device for solar cell of miniature satellite power system and control method thereof

Abstract

The invention discloses a maximum power tracking device for a solar cell of a miniature satellite power system and a control method thereof. The maximum power tracking device comprises a control unit and a plurality of power output units. The control unit adjusts the working mode of a corresponding DC-DC conversion module according to input voltage and output voltage collected by an information collection module in one power output unit, if the work is in a boosting mode or a step-down mode, the control unit carries out MPPT control according to the output power of the present moment and the last moment, and if the DC-DC conversion modules have failures, and corresponding failure mode modules are opened. According to the maximum power tracking device, based on one control unit, a plurality of the DC-DC conversion modules can be controlled in a centralized mode, the step-down mode, the boosting mode and the shoot-through mode of the DC-DC conversion modules can be achieved, the modes of the failure mode modules can be switched by the control unit when the DC-DC conversion modules have failures, and therefore connection from the input end to the output end can be guaranteed.

Description

Technical field [0001] The invention relates to the field of switching power supplies for aerospace devices and the field of program control, in particular to a solar battery maximum power tracking device and a control method thereof suitable for a micro-satellite power supply system. Background technique [0002] Micro-satellites refer to satellites with a mass below 100Kg, and their power supply is generally composed of solar cells and storage batteries. Since the load output curve of a solar cell is related to external conditions (light, temperature), its operating point on the same solar cell output curve is also related to the load resistance, and there is a maximum power output point on the curve. In order to make the solar cell work at the maximum power point, a device that can monitor and adjust the output state of the solar cell in real time is needed to provide more energy supply for the satellite. [0003] Such as figure 1 As shown, the prior art MPPT (Maximum Power Poi...

AI Technical Summary

Problems solved by technology

However, the existing MPPT device has three disadvantages: the first, the operating frequency of the control unit MCU of the prior art is low, so that the duty cycle resolution of the output control signal PWM wave is low, which cannot meet the requirements of high-precision control; If the DSP is used as the control unit, generally the DSP has an internal integrated PWM module, which can be used by directly configuring the registers.

However, the general output interface of the PWM module is very limited, which is not enough to meet the control needs of multiple sub-boards of the satellite power supply.

In addition, the power consumption of DSP is high, which will reduce the overall efficiency.

Second, in the current MPPT device, the discrete DCDC topology is generally BUCK step-down type or BOOST step-up type. Can work in step-up or step-down state, but cannot meet the working conditions of both step-down and step-up

[0004] In addition, there are currently integrated chips or circuit boards capable of maximum power tracking on the market, but these devices have the following disadvantages: First, such devices are generally suitable for occasions with KW-level power requirements, and have low accuracy in a small range of power. Suitable for micro-satellite applications with power consumption of tens of watts

Secondly, such devices generally have fixed interfaces and a definite topology, and cannot be switched flexibly

Finally, the algorithm has been solidified inside such devices and cannot be optimized according to the actual situation

To sum up, the MPPT devices in the prior art have deficiencies in both hardware and software, and cannot meet the needs of micro-satellite power system applications

Images