Constant-current power supply unit for instantaneous high-power load

Abstract

The invention provides a constant-current power supply unit for an instantaneous high-power load, relates to a system composition and a principle of a novel constant-current power supply unit based on a super capacitor, belongs to the field of power supply system design, and aims to provide a general scheme for solving the problem of power supply of the instantaneous high-power load on a satellite platform. The power supply unit is mainly formed by connecting a constant-current charging module, a super capacitor module and a constant-current discharging module in series. Wherein the super capacitor module is used as an energy power container, the constant-current charging module is used for realizing isolation between a capacitor and a power bus and charging management, and the constant-current discharging module is used for realizing isolation between the capacitor and a load and discharging management. The three modules are integrated into a whole and are externally connected with a bus and a load power supply, and constant-current power supply for an instantaneous high-power load can be realized by utilizing four led-out control pins.

Description

Technical Field

[0001] The invention provides a constant current power supply unit for instantaneous high-power loads, relates to the system composition and principle of a novel constant current power supply unit based on a supercapacitor, and belongs to the field of power supply system design. Background Art

[0002] With the rapid development of aerospace technology, the requirements of satellite-borne equipment on power supply systems are increasing day by day, especially when performing complex scientific experiments, high-resolution imaging, high-speed communications and high-energy detection tasks. Instantaneous high-power load power supply has become a key challenge. At present, satellite-borne power supply systems mostly use traditional voltage-stabilized power supply designs, which connect the bus directly to the load after shunt regulation and filtering. Although this type of design can meet conventional low-power requirements, when facing instantaneous high-power loads, there are problems such as large output voltage fluctuations, slow system response speed, and low energy conversion efficiency.

[0003] Specifically, traditional onboard power systems often have difficulty providing sufficient high-power output in a very short period of time, causing the payload equipment to face the risk of insufficient power supply when starting or performing high-power tasks, which in turn affects the success rate of mission execution and the service life of the equipment. In addition, the traditional power system is large in size and weight, which is not conducive to increasing the satellite's payload and reducing operating costs.

[0004] In recent years, although some studies have attempted to improve the performance of satellite-borne power systems by optimizing power topology, adopting advanced power electronic devices, and introducing advanced control algorithms, these solutions still have limitations in terms of instantaneous high-power output and are unable to meet the growing demands of satellite-borne payloads.

[0005] In view of the above technical background, the present invention proposes a constant current power supply unit for instantaneous high-power loads, aiming to provide a universal and reliable constant current power supply solution for instantaneous high-power onboard payloads through innovative power supply design and efficient energy management strategies. Summary of the invention

[0006] (I) Purpose of the invention

[0007] The instantaneous high-power load places high demands on the power supply system of the satellite platform. The traditional load direct bus connection solution often leads to excessive instantaneous load on the platform power supply system. Many satellite platforms cannot meet the carrying requirements, which greatly limits the universality of the load. The purpose of the present invention is to design a new power supply unit to provide a universal solution for solving the power supply problem of instantaneous high-power loads on satellite platforms.

[0008] (II) Technical solution

[0009] The present invention provides a power supply unit for instantaneous high-power load based on supercapacitor, which is mainly composed of three parts connected in series: a constant current charging module, a supercapacitor module, and a constant current discharge module. The supercapacitor module is used as an energy power container, and the constant current charging module realizes the isolation of the capacitor from the power bus and the charging management, and the constant current discharge module realizes the isolation of the capacitor from the load and the discharge management.

[0010] The constant current charging module uses a bidirectional four-switch synchronous buck-boost controller chip to form a buck-boost circuit system with output voltage feedback and input and output current monitoring. The enable pin of the chip is controlled to control the overall enablement of the constant current charging module. The chip adds the input and output current measurements to the voltage feedback terminal through an external current error feedback circuit, thereby realizing constant current control of charging. By reasonably selecting the value of the feedback resistor on the current error feedback circuit, a reasonable charging current value is obtained to meet the average power demand of the load and the overall requirements of the on-board power supply. By reasonably selecting the value of the voltage divider resistor on the voltage feedback loop, the output voltage is matched with the operating voltage of the supercapacitor. In addition, the NMOS signal switch is used to control the conduction between the supercapacitor and the bus ground to achieve isolation between the supercapacitor module and the bus.

[0011] The supercapacitor module is composed of several capacitors and their charging protection circuits connected in series. It usually receives charging from the constant current charging module and stores energy in itself. When the load needs electricity, it can instantly release a large amount of electric energy. The charging protection circuit uses a supercapacitor charging protection chip to control the CMOS discharge current. Under normal circumstances, the voltage between the positive and negative electrodes of the capacitor will not exceed the nominal voltage. During charging and discharging, when the voltage at both ends of a capacitor is over-voltage, the corresponding CMOS switch will be turned on to release the excess charge through the discharge resistor, thus ensuring that the voltage between the capacitors is basically balanced during the charging process. The positive electrode of the supercapacitor module is directly connected to the positive output of the constant current charging module and the positive input of the constant current discharge module; the negative electrode is isolated from the bus ground by an NMOS switch and is directly connected to the negative input of the constant current discharge module. The supercapacitor module is glue-filled as a whole and can withstand a thermal vacuum environment.

[0012] The constant current discharge module and the constant current charging module use the same buck-boost circuit system. By reasonably selecting the value of the feedback resistor on the current error feedback circuit, the output current is the rated current of the load. By reasonably selecting the value of the voltage divider resistor on the voltage feedback loop, the output voltage matches the rated voltage of the load. The printed circuit board is designed with high current routing to withstand large instantaneous current input and output. When the load is working, the enable end is always turned on, and the NMOS on the control end is pulled high for a short time to provide instantaneous power supply to the load.

[0013] (III) Advantages

[0014] The advantages of the constant current power supply unit for instantaneous high-power loads of the present invention are:

[0015] ① The constant current power supply unit proposed in the present invention can significantly reduce the maximum power demand of the instantaneous power load on the onboard power supply system, so that the instantaneous high-power load can be flexibly carried on different satellite platforms and is no longer limited by the instantaneous load capacity of the platform power supply system.

[0016] ② The constant current power supply unit proposed in the present invention has a supercapacitor group with fast response capability and high power output characteristics, which can ensure that the load can obtain stable and reliable power support under instantaneous high power demand.

[0017] ③ The constant current power supply unit proposed in the present invention can adjust the voltage and current input from the bus and the voltage and current output to the load conveniently according to the specific application situation, and has certain stability and accuracy.

[0018] ④ The constant current power supply unit proposed in the present invention has modular characteristics and is easy to integrate between the payload module and the power supply bus. ⑤ The constant current power supply unit proposed in the present invention can simplify the complexity of the satellite power supply system and improve the operating efficiency and reliability of the overall system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a diagram of the overall structure of a constant current power supply unit for instantaneous high-power loads.

[0020] Figure 2 It is a schematic diagram of the buck-boost circuit system of the constant current charging module and the constant current discharging module described in the present invention.

[0021] Figure 3 It is a schematic diagram of the changes in the voltage of the supercapacitor module and the control signal of the constant current discharge module when the constant current power supply unit described in the present invention works under an exemplary load. DETAILED DESCRIPTION

[0022] The following describes exemplary embodiments of the present invention in conjunction with the accompanying drawings so that those skilled in the art can better understand and implement the present invention. The following examples are only for example, and should not be understood as limiting the present invention to the exemplary examples described herein.

[0023] The working characteristics of a certain satellite-borne high-power laser are that it emits laser signals with a period of 200ms and a duty cycle of 5%. Its operating voltage is 48V and its current is 36A, so its instantaneous power is 1728W and its average power during operation is 86.4W. If the on-board power bus is used for direct power supply, the power of the laser when it is turned on will exceed 1.7kW. For general small and medium-sized satellite platforms, such instantaneous power is difficult to bear, and a targeted power supply design must be carried out. Installing the power supply unit described in the present invention in front of the laser can solve this problem well. The specific implementation method of the present invention is described below.

[0024] like Figure 1 As shown, the constant current power supply unit used consists of three parts: a constant current charging module, a super capacitor module and a constant current discharge module. The first two constitute a charging circuit, and the latter two constitute a power supply circuit. The satellite bus voltage serves as the input of the constant current charging module, and the laser is connected to the output end of the constant current discharge module as an instantaneous high-power load.

[0025] The supercapacitor module of the constant current power supply unit uses 20 25F capacitors with a withstand voltage of 2.7V connected in series. The capacitor balancing circuit ensures that each capacitor is evenly charged, with an average single capacitor voltage distribution of 2.65V. The operating voltage of the entire module is 53V, and the equivalent capacitance is 1.25F. It can be calculated from E=1 / 2*CU^2 that the stored electrical energy is approximately 1756J. The minimum voltage allowed by the constant current drive module is calculated as 18V, and the effective electrical energy is approximately 1553J, which meets the normal working requirements of the load.

[0026] The busbar starts to supply power when the satellite enters orbit normally. The busbar voltage is 46V. At this time, the voltage across the supercapacitor module is close to 0V. The input end of the constant current charging module is the on-board busbar, and the output end is the supercapacitor module. The constant current charging module is turned on by pulling up the level of the enable end and the control end, and the constant current discharge module remains turned off. The bidirectional four-switch buck-boost circuit structure is as follows: Figure 2 As shown, the controller connects the gates of four CMOS tubes Q1, Q2, Q3, and Q4. Initially, the chip of the constant current charging module controls Q1 to turn on, Q2 to turn off, and Q3 and Q4 to switch alternately in PWM mode, that is, the supercapacitor module is charged in Buck mode with the set maximum current of 5A; when the capacitor voltage is close to the bus voltage, it switches to Buck-Boost mode, and the four switches are controlled by the chip to switch alternately in PWM; when the capacitor voltage exceeds the bus voltage, it switches to Boost mode, Q1 and Q2 are switched alternately in PWM mode, Q3 is turned on, Q4 is turned off, and charging continues at the maximum current. Finally, after about 13s, the supercapacitor module reaches the working voltage and meets the load operation conditions.

[0027] During the load working period, the enable terminal level of the constant current discharge module is pulled high to turn on the module, and the constant current charging module also remains on. The input end of the constant current discharge module is the supercapacitor module, and the output end is the laser. The supercapacitor module provides instantaneous discharge current, and at the same time draws power from the bus to replenish the power to meet the long-term use requirements of the load. The constant current discharge module is mainly based on the Buck mode described in the previous paragraph. The control end inputs a CMOS level signal with a duty cycle of 5% and a period of 200ms, which can control the laser to emit lasers in the same pattern. In this working mode, the voltage of the supercapacitor module will be as follows Figure 3 As shown in the change, when the control terminal is pulled high in each cycle, the output power is greater than the input power, and the voltage changes from V h Drop to V l When the control terminal is pulled low, the output current is turned off, and the constant current charging gradually increases the voltage to V h The voltage is always kept near the operating voltage during the whole process, and the maximum current of the satellite bus to the load is 5A. The power subsystem no longer needs to design a power supply module for the laser.

[0028] The constant current power supply unit described in the present invention integrates three modules into a whole, is externally connected to a satellite bus and a load power supply, and leads to four GPIOs. Through the above steps, a controlled constant current power supply can be provided for the laser.

Claims

1. A constant current power supply unit for instantaneous high power load, characterized in that: It is composed of three parts connected in series: a constant current charging module, a supercapacitor module, and a constant current discharge module. The supercapacitor module serves as an energy power container. The constant current charging module realizes the isolation of the capacitor from the power bus and the charging management, and the constant current discharge module realizes the isolation of the capacitor from the load and the discharge management.

2. A constant current power supply unit for instantaneous high power load according to claim 1, characterized in that: The constant current charging module uses a bidirectional four-switch synchronous buck-boost control chip, has a wide input and output voltage range, and has an output voltage feedback and a current error feedback loop. The output voltage can be adjusted by replacing the voltage divider resistor, and the output constant current value can be changed by replacing the resistor at the current error feedback loop.

3. A constant current power supply unit for instantaneous high power load according to claim 1, characterized in that: The supercapacitor module is composed of multiple supercapacitors and their charging protection circuits connected in series, and has a large capacity. The charging protection circuit adopts a supercapacitor charging protection chip to control the CMOS switch discharge current. The voltage of each capacitor is basically balanced during charging and discharging, and the module voltage value will not change significantly during load operation. The module is glue-filled and can withstand a thermal vacuum environment.

4. A constant current power supply unit for instantaneous high power load according to claim 1, characterized in that: The constant current discharge module uses a bidirectional four-switch synchronous buck-boost control chip, has a wide input and output voltage range, and has an output voltage feedback and a current error feedback loop. The output voltage can be adjusted by replacing the voltage divider resistor, and the output constant current value can be changed by replacing the resistor at the current error feedback loop. The load is discharged instantaneously by quickly switching the NMOS level at the output end. It can withstand large current input and output and has small standby power consumption.

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