Hardware MPPT control device and method for space power supply

Abstract

The invention discloses a hardware MPPT (Maximum Power Point Tracking) control device and method for a space power supply, and belongs to the technical field of space power supplies. The hardware MPPT control device comprises a Buck circuit topology and an MTTP control circuit; the MTTP control circuit comprises a peak pickup circuit which picks up the maximum point of the power of the solar cell through charging and discharging of an RC circuit; the MPPT reference circuit is used for keeping the maximum power point of the solar cell and generating a reference signal Vmpp of MPPT; the MPPT modulation circuit is used for modulating Vsa to work on the maximum power of the solar cell by changing the duty ratio of Buck by taking a Vmpp signal representing the maximum power of the solar cell as a reference; the mirror current source sampling circuit is used for copying high-end current output by the solar cell array; and the pulse modulation multiplier realizes the product of the voltage and the current of the solar cell by using an MPPT modulation circuit and a mirror current source sampling circuit.

Description

Technical Field

[0001] This invention belongs to the field of space power technology, specifically relating to a hardware MPPT control device and method for space power. Background Technology

[0002] As is well known, space power systems, as core energy supply equipment for spacecraft, play an irreplaceable and crucial role in various space missions. A typical satellite power system architecture typically employs an energy solution consisting of three main modules: a solar cell array, an energy storage battery bank, and a power controller. The solar cell array, as the primary power generation unit, is responsible for converting solar energy into electrical energy; the energy storage battery bank, as the energy storage unit, provides power support during shadow periods or peak loads; and the power controller, as the system's intelligent central hub, coordinates and manages the entire power supply process, ensuring a continuous and stable power supply for the spacecraft throughout its mission cycle. With the continuous development of aerospace technology, space power systems are also constantly evolving, with development goals mainly reflected in four aspects: extending system lifespan, reducing overall weight, minimizing equipment size, and improving energy conversion efficiency. In the field of power control technology, the mainstream solar cell regulation schemes can currently be divided into two types: one is a direct energy transfer parallel power supply mode based on S3R (Sequential Switching Shunt Regulator), and the other is a series power supply mode using Maximum Power Point Tracking (MPPT) technology. These two technical approaches each have their own characteristics: the S3R scheme is known for its simple circuit structure, high operational reliability, and excellent energy conversion efficiency, but its utilization rate of solar cells is low in the early stages of the mission, requiring a large design redundancy. In contrast, the MPPT scheme, although more complex in circuitry and slightly less efficient overall than S3R, can maximize the utilization of solar cell output power throughout the entire mission cycle, especially in the early stages. In current space power engineering practice, the implementation of MPPT control circuits mainly falls into two categories: one is a digital control scheme based on a digital signal processor (DSP), and the other is a control system built using traditional analog circuits. Considering the special characteristics of the space environment, including harsh conditions such as radiation and temperature variations, the MPPT system implemented with analog circuits demonstrates unique value in space applications due to its simple structure and high reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a hardware MPPT control device and method for space power supply, which simplifies MPPT control circuit, improves solar cell utilization, and reduces power system complexity.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A hardware MPPT control device for space power supply includes a Buck step-down circuit topology and an MTTP control circuit; wherein the MTTP control circuit includes:

[0006] The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit;

[0007] The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp.

[0008] The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck.

[0009] A mirror current source sampling circuit is used to replicate the high-end current output by the solar cell array;

[0010] The pulse modulation multiplier uses an MPPT modulation circuit and a mirror current source sampling circuit to realize the product of solar cell voltage and current.

[0011] Preferably, the Buck step-down circuit topology includes a MOSFET, a first diode, an inductor, a second diode, an input filter capacitor, and an output filter capacitor; wherein: the drain (D) of the MOSFET is connected to the positive terminal of the solar cell array through a sampling resistor; the source (S) of the MOSFET is connected to the positive terminal of the battery pack through an inductor and a second diode; the negative terminal of the solar cell array is connected to the negative terminal of the battery pack; the negative terminal of the solar cell array is connected to the source (S) of the MOSFET through a first diode; the drain of the MOSFET is connected to the negative terminal of the solar cell array through the input filter capacitor; and the cathode of the second diode is grounded through the output filter capacitor.

[0012] Preferably, the peak pickup circuit includes an optional gain operational amplifier and a low-pass filter circuit composed of resistor No. 1 and resistor No. 2; wherein: the output terminal of the mirror current source sampling circuit is grounded in sequence through resistor No. 1 and resistor No. 2, the output terminal of the mirror current source sampling circuit is connected to the positive terminal of the optional gain operational amplifier No. 1 through resistor No. 1, and the negative terminal of the optional gain operational amplifier No. 1 is connected to the output terminal of the optional gain operational amplifier No. 1 through a fixed resistor.

[0013] Preferably, the pulse modulation multiplier includes two transistors.

[0014] Preferably, the MPPT reference circuit includes a comparator, a D flip-flop, and a transistor connected in sequence.

[0015] Preferably, the MPPT modulation circuit includes a second selectable gain operational amplifier.

[0016] Preferably, the mirror current source sampling circuit includes three transistors.

[0017] A second objective of this invention is to provide a hardware MPPT control method for space power supplies, comprising:

[0018] The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit;

[0019] The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp.

[0020] The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference, and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck.

[0021] The high-end current output of the solar cell array is replicated using the mirror current source sampling circuit (1);

[0022] The pulse modulation multiplier uses an MPPT modulation circuit and a mirror current source sampling circuit (1) to realize the product of solar cell voltage and current.

[0023] Preferably, the Buck step-down circuit topology includes a MOSFET, a first diode, an inductor, a second diode, an input filter capacitor, and an output filter capacitor; wherein: the drain (D) of the MOSFET is connected to the positive terminal of the solar cell array through a sampling resistor; the source (S) of the MOSFET is connected to the positive terminal of the battery pack through an inductor and a second diode; the negative terminal of the solar cell array is connected to the negative terminal of the battery pack; the negative terminal of the solar cell array is connected to the source (S) of the MOSFET through a first diode; the drain of the MOSFET is connected to the negative terminal of the solar cell array through the input filter capacitor; and the cathode of the second diode is grounded through the output filter capacitor.

[0024] Preferably, the peak pickup circuit includes an optional gain operational amplifier and a low-pass filter circuit composed of resistor No. 1 and resistor No. 2; wherein: the output terminal of the mirror current source sampling circuit is grounded in sequence through resistor No. 1 and resistor No. 2, the output terminal of the mirror current source sampling circuit is connected to the positive terminal of the optional gain operational amplifier No. 1 through resistor No. 1, and the negative terminal of the optional gain operational amplifier No. 1 is connected to the output terminal of the optional gain operational amplifier No. 1 through a fixed resistor.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention discloses a hardware MPPT control device for space power supplies. This device innovatively utilizes a pulse width modulator and a mirror current source sampling circuit in a power converter to accurately measure the output voltage and current of a solar cell array. By using the pulse width modulation and mirror current source sampling circuit, it achieves the sampling of the product of the solar cell voltage and current, i.e., the power. This design not only maintains the core functions of traditional MPPT control, but also greatly simplifies the complexity of traditional MPPT control circuits through ingenious circuit structure optimization, thereby improving the reliability and stability of the system.

[0027] This invention, based on a basic circuit architecture, requires only the addition of two high-precision operational amplifiers, one high-speed comparator, one D-type flip-flop, a few transistors, and some external resistors and capacitors to fully implement the MPPT control algorithm. This modular design approach simplifies the entire control circuit structure, clearly defining the functions of each module, ensuring both control accuracy and improved system anti-interference capabilities. Furthermore, the use of conventional electronic components reduces manufacturing costs and significantly enhances circuit reliability and maintainability, making it highly suitable for widespread application in photovoltaic power generation systems. Attached Figure Description

[0028] Figure 1 Circuit diagram provided for a preferred embodiment of the present invention;

[0029] Figure 2 The following simulation waveform diagrams are provided for the preferred embodiments of the present invention.

[0030] Among them: 1. Mirror current source sampling circuit; 2. Buck step-down circuit topology. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1:

[0033] Please see Figures 1 to 2 As shown, a hardware MPPT control device for space power supply mainly includes a Buck step-down circuit topology 2 and an MTTP control circuit; wherein:

[0034] Buck step-down circuit topology 2 converts the electrical energy parameters generated by the solar cell array into the charging parameters of the battery pack.

[0035] The MTTP control circuit includes:

[0036] The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit;

[0037] The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp.

[0038] The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck.

[0039] The mirror current source sampling circuit 1 is used to replicate the high-end current output by the solar cell array;

[0040] The pulse modulation multiplier utilizes an MPPT modulation circuit and a mirror current source sampling circuit 1 to realize the product of solar cell voltage and current.

[0041] Please see Figure 1 The Buck step-down circuit topology 2 includes a MOSFET, diode D1, inductor Lzw, diode D2, input filter capacitor, and output filter capacitor. Specifically: the drain (D) of the MOSFET is connected to the positive terminal of the solar array via a sampling resistor; the source (S) of the MOSFET is connected to the positive terminal of the battery pack via the inductor and diode D2; the negative terminal of the solar array is connected to the negative terminal of the battery pack; the negative terminal of the solar array is connected to the source (S) of the MOSFET via diode D1; the drain of the MOSFET is connected to the negative terminal of the solar array via the input filter capacitor; and the cathode of diode D2 is grounded via the output filter capacitor.

[0042] The peak pickup circuit includes a selectable gain operational amplifier and a low-pass filter circuit composed of resistor No. 1 and resistor No. 2; wherein: the output terminal of the mirror current source sampling circuit 1 is grounded in sequence through resistor No. 1 and resistor No. 2, the output terminal of the mirror current source sampling circuit 1 is connected to the positive terminal of the selectable gain operational amplifier No. 1 through resistor No. 1, and the negative terminal of the selectable gain operational amplifier No. 1 is connected to the output terminal of the selectable gain operational amplifier No. 1 through a fixed resistor.

[0043] The pulse modulation multiplier includes two transistors.

[0044] The MPPT reference circuit includes a comparator, a D flip-flop, and a transistor connected in sequence.

[0045] The MPPT modulation circuit includes a second selectable gain operational amplifier.

[0046] The mirror current source sampling circuit 1 includes three transistors.

[0047] The above embodiment includes a Buck buck circuit topology, which is essentially a DC-DC converter. The non-isolated Buck buck DC-DC converter in the space power supply is selected as the main power conversion topology.

[0048] The MPPT control signal changes the duty cycle of MOS1, causing the solar array to operate at its maximum power point. This converts the maximum solar energy to the battery terminal via a DC-DC converter, charging the battery or supplying power to the load. The MPPT control circuit mainly consists of a pulse-width modulation (PWM) multiplier, a peak pickup circuit, an MPPT reference circuit, and an MPPT modulation circuit. The PWM multiplier utilizes the duty cycle of the PWM modulator in the DC-DC converter to achieve the product of voltage and duty cycle. It samples the solar cell current by sampling the high-side current input of the DC-DC converter. The circuit uses PWM and a mirrored current source to sample the product of the solar cell voltage and current, i.e., the power. Changes in solar cell power are reflected in the low-pass filter circuit composed of RP and CP in the peak pickup circuit. The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of an RC circuit. The MPPT reference circuit maintains the maximum power point of the solar cell and generates the MPPT reference signal Vmpp. The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference. By changing the duty cycle of Buck, it modulates Vsa to operate at the maximum power of the solar cell. Ultimately, it achieves maximum power point tracking of the solar cell, maximizing the utilization of the solar cell's power.

[0049] This invention achieves the maximum power utilization of solar cells in a space power system. The MPPT control circuit is simple and reliable, and the components used have good versatility, a small number of components, and excellent adaptability to the space environment, which can efficiently reduce the weight and volume of the power system.

[0050] Compared to traditional MPPT hardware circuit implementations, this invention is simpler. It does not use complex multiplier chips or complex control circuits composed of chips such as sample-and-hold circuits. Instead, it uses the pulse width modulator required by the DC-DC converter itself and the mirror current source circuit for sampling the input current to achieve MPPT control based on the pulse width modulation multiplier. The control circuit is simple and reliable.

[0051] A hardware MPPT control method for space power supplies, utilizing the hardware MPPT control device for space power supplies described in the above embodiments, completes the following steps:

[0052] The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit;

[0053] The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp.

[0054] The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference, and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck.

[0055] The high-end current output by the solar cell array is replicated using the mirror current source sampling circuit 1;

[0056] The pulse modulation multiplier utilizes an MPPT modulation circuit and a mirror current source sampling circuit 1 to realize the product of solar cell voltage and current.

[0057] The Buck step-down circuit topology 2 consists of several key electronic components, mainly including a power MOSFET, a freewheeling diode (number 1), an energy storage inductor, a rectifier diode (number 2), an input filter capacitor, and an output filter capacitor. The specific connections are as follows: the drain (D) of the power MOSFET is first connected in series with a precision sampling resistor, and then connected to the positive output terminal of the solar cell array; the source (S) of the power MOSFET is sequentially connected to the input terminal of the energy storage inductor and the anode of the rectifier diode (number 2), and finally connected to the positive terminal of the battery pack to form the main power circuit. In terms of circuit layout, the negative output terminal of the solar cell array is directly connected to the negative terminal of the battery pack to form a common ground circuit. Simultaneously, the negative terminal of the solar cell array is also connected in reverse parallel to the source (S) of the power MOSFET through the freewheeling diode (number 1), forming a freewheeling protection circuit. To improve system stability, an input filter capacitor is connected in parallel between the drain (D) of the power MOSFET and the negative terminal of the solar cell array to suppress high-frequency noise on the input side; while the cathode of the second rectifier diode is grounded through the output filter capacitor to achieve filtering and smoothing of the output voltage.

[0058] The peak pickup circuit uses a high-precision selectable gain operational amplifier as its core processing unit, coupled with a first-order low-pass filter network composed of precision resistors No. 1 and No. 2. The specific circuit connection is as follows: the output signal terminal of the mirror current source sampling circuit 1 is first connected in series with precision resistor No. 1, and then grounded through precision resistor No. 2 to form a voltage divider network; simultaneously, the output signal of the mirror current source sampling circuit 1 is directly connected to the non-inverting input terminal (positive terminal) of the selectable gain operational amplifier No. 1 through precision resistor No. 1. In the feedback loop of the selectable gain operational amplifier No. 1, its inverting input terminal (negative terminal) is connected to the output terminal of the operational amplifier through a feedback resistor of fixed value, forming a standard non-inverting proportional amplifier circuit structure to achieve precise amplification and processing of the sampled signal.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hardware MPPT control device for space power supply, characterized in that, This includes a Buck step-down circuit topology (2) and an MTTP control circuit; wherein the MTTP control circuit includes: The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit; The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp. The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck. The mirror current source sampling circuit (1) is used to replicate the high-end current output by the solar cell array; The pulse modulation multiplier utilizes the MPPT modulation circuit and the mirror current source sampling circuit (1) to realize the product of the solar cell voltage and current.

2. The hardware MPPT control device for space power supply according to claim 1, characterized in that: The Buck step-down circuit topology (2) includes a MOSFET, a first diode, an inductor, a second diode, an input filter capacitor, and an output filter capacitor; wherein: the drain (D) of the MOSFET is connected to the positive terminal of the solar cell array through a sampling resistor, and the source (S) of the MOSFET is connected to the positive terminal of the battery pack through an inductor and a second diode; the negative terminal of the solar cell array is connected to the negative terminal of the battery pack, and the negative terminal of the solar cell array is connected to the source (S) of the MOSFET through a first diode; the drain (D) of the MOSFET is connected to the negative terminal of the solar cell array through an input filter capacitor, and the cathode of the second diode is grounded through an output filter capacitor.

3. The hardware MPPT control device for space power supply according to claim 2, characterized in that: The peak pickup circuit includes a selectable gain operational amplifier and a low-pass filter circuit composed of resistor No. 1 and resistor No. 2; wherein: the output terminal of the mirror current source sampling circuit (1) is grounded in sequence through resistor No. 1 and resistor No. 2, the output terminal of the mirror current source sampling circuit (1) is connected to the positive terminal of the selectable gain operational amplifier No. 1 through resistor No. 1, and the negative terminal of the selectable gain operational amplifier No. 1 is connected to the output terminal of the selectable gain operational amplifier No. 1 through a fixed resistor.

4. The hardware MPPT control device for space power supply according to claim 3, characterized in that: The pulse modulation multiplier includes two transistors.

5. The hardware MPPT control device for space power supply according to claim 3, characterized in that: The MPPT reference circuit includes a comparator, a D flip-flop, and a transistor connected in sequence.

6. The hardware MPPT control device for space power supply according to claim 3, characterized in that, The MPPT modulation circuit includes a second selectable gain operational amplifier.

7. The hardware MPPT control device for space power supply according to any one of claims 1-6, characterized in that: The mirror current source sampling circuit (1) includes three transistors.

8. A hardware MPPT control method for a space power supply, characterized in that, include: The peak pickup circuit picks up the maximum power of the solar cell through the charging and discharging of the RC circuit; The MPPT reference circuit holds the maximum power point of the solar cell and generates the MPPT reference signal Vmpp. The MPPT modulation circuit uses the Vmpp signal, which characterizes the maximum power of the solar cell, as a reference, and modulates Vsa to operate at the maximum power of the solar cell by changing the duty cycle of Buck. The high-end current output of the solar cell array is replicated using the mirror current source sampling circuit (1); The pulse modulation multiplier uses an MPPT modulation circuit and a mirror current source sampling circuit (1) to realize the product of solar cell voltage and current.

9. The hardware MPPT control method for space power supply according to claim 8, characterized in that, The Buck step-down circuit topology (2) includes a MOSFET, a first diode, an inductor, a second diode, an input filter capacitor, and an output filter capacitor; wherein: the drain (D) of the MOSFET is connected to the positive terminal of the solar cell array through a sampling resistor, and the source (S) of the MOSFET is connected to the positive terminal of the battery pack through an inductor and a second diode; the negative terminal of the solar cell array is connected to the negative terminal of the battery pack, and the negative terminal of the solar cell array is connected to the source (S) of the MOSFET through a first diode; the drain (D) of the MOSFET is connected to the negative terminal of the solar cell array through an input filter capacitor, and the cathode of the second diode is grounded through an output filter capacitor.

10. The hardware MPPT control method for space power supply according to claim 9, characterized in that, The peak pickup circuit includes a selectable gain operational amplifier and a low-pass filter circuit composed of resistor No. 1 and resistor No. 2; wherein: the output terminal of the mirror current source sampling circuit (1) is grounded in sequence through resistor No. 1 and resistor No. 2, the output terminal of the mirror current source sampling circuit (1) is connected to the positive terminal of the selectable gain operational amplifier No. 1 through resistor No. 1, and the negative terminal of the selectable gain operational amplifier No. 1 is connected to the output terminal of the selectable gain operational amplifier No. 1 through a fixed resistor.

Images