CN109873560B - High-power high-stability boosting power supply system - Google Patents

Abstract

The invention relates to a high-power and high-stability booster power supply system, which is directly boosted to the satellite load voltage for the first time and then transmitted. After the booster power supply system is adopted, the requirement of simultaneously supplying power to multiple satellite loads can be met, and the load satellite can be saved. The battery consumption during the flight of the aircraft reduces the design difficulty of the payload satellite battery and improves the power supply efficiency of the payload satellite power supply system. The use of the boost power supply system also solves the problem of insufficient power supply capability of the aircraft for the long-distance high-power power supply of the payload satellite, which makes the design of the long-distance power supply cable simple and the loss on the cable is small, which improves the power supply efficiency. It can also stabilize the bus voltage, which makes the design of the load secondary power module easier. Replacing the booster power components in the booster circuit and changing the threshold of the comparator can meet various bus voltage requirements of the satellite, with good scalability, which opens up space for the booster power supply system of the aircraft.

Description

A high-power and high-stability boost power supply system

technical field

The invention relates to a high-power and high-stability boost power supply system, which belongs to the field of aircraft electrical system design.

Background technique

The electrical power supply system of the launch vehicle is the foundation of all electrical equipment in the system, and it is also the key to the reliability of the overall quality of the system. With the continuous development and progress of the design of the electrical system of the launch vehicle, the circuit is becoming more and more complex, and the requirements for the power output and busbar characteristics of the power supply are getting higher and higher. The electrical power supply system usually uses batteries and secondary power modules. The stored chemical energy is converted into electrical energy by the battery and supplied to the subsequent secondary power module. The secondary power module of each device converts the high-voltage busbar of the battery into the required low-voltage busbar through DC/DC, and the power consumption is generally about several watts to several tens of watts. The launch vehicle provides a power path for the payload satellite, and the payload satellite completes the power supply of the equipment on the rocket and the charging of the battery on the rocket. Before the launch, the ground power supply is disconnected, and the power supply of the payload satellite equipment during the flight of the launch vehicle is provided by the battery of the payload satellite itself.

The flight time of the aircraft is long, and the battery of the payload satellite itself needs to be designed to increase the capacity, increase the weight of the payload satellite, and reduce the effective utilization rate of the payload satellite. Because the aircraft instrument is far away from the payload satellite instrument, the voltage drop of the direct battery supply voltage is large. Under the high power operation of the payload satellite, the cable loss and heat generation are large, which is not conducive to the control of the thermal environment of the aircraft.

How to provide a power supply system suitable for the long-term flight of the aircraft is a technical problem to be solved urgently in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a high-power and high-stability boost power supply system, which improves the power supply efficiency of the load satellite power system after boosting the battery voltage to the satellite load voltage for transmission.

The object of the present invention is achieved through the following technical solutions:

A high-power and high-stability boost power supply system is provided, comprising: a battery, a command switch control circuit, a boost power circuit, a boost control PWM loop and a protection circuit;

After the command switch control circuit receives the power-on command, it controls the power-on switch to close, and the boost power circuit boosts the battery voltage to the required output voltage; after the command switch control circuit receives the power-on command, it controls the power-on switch. The electrical switch is closed, and the boost power circuit supplies power to the load;

The boost control PWM loop is used to reduce the PWM duty cycle and reduce the output voltage when the power supply voltage to the load exceeds the set first voltage threshold or the load current is less than the set first output current threshold; otherwise, the PWM duty cycle is increased. ratio, increase the output voltage;

The protection circuit stops power supply when the output voltage is over-voltage and the output current is over-current; when the output current exceeds the current limiting threshold, the boost control PWM loop is controlled to keep the current PWM duty cycle unchanged.

Preferably, it also includes an input filter network and an output filter network; the input filter network is used to filter out the interference on the battery power supply bus; the output filter network includes a high-frequency filter capacitor circuit and a low-frequency filter capacitor circuit to stabilize the output voltage of the boost power circuit .

Preferably, the boost power circuit adopts a Weinberg boost push-pull circuit.

Preferably, the boosting power circuit boosts the battery voltage through the transformer M2; when the power tubes Q1 and Q2 are turned on, the diodes D2 and D1 are respectively caused to be turned on under the action of the coupling transformer M1, and the boosted voltage is output. voltage, at this time the freewheeling diode D3 of the transformer M2 is turned off; when the power tubes Q1 and Q2 are turned off, the freewheeling diode D3 is turned on to maintain the voltage output.

Preferably, the boost control PWM loop includes a first comparator, a second comparator and a PWM controller;

The first comparator compares the output voltage of the boost power circuit with the first voltage threshold, if it is higher than the first voltage threshold, it outputs a high level, otherwise it outputs a low level; the negative input end of the second comparator is connected to the same time. Input the output level of the comparator 1 and the voltage converted by the inversely proportionally adjusted load current. If the first comparator outputs a high level, or the load current is less than the first output current threshold, the second comparator outputs a low level to PWM controller, the PWM controller reduces the PWM duty cycle and reduces the output voltage; on the contrary, increases the PWM duty cycle and increases the output voltage.

Preferably, the first voltage threshold is the standard value of the required output voltage, and the first output current threshold is the current required when the load is in an average power state.

Preferably, the protection circuit includes a third comparator, a fourth comparator, a fifth comparator and an AND gate;

The third comparator compares the output voltage of the boost power circuit with the overvoltage threshold, and outputs a high level to the first input end of the AND gate when the overvoltage threshold is exceeded;

The fourth comparator compares the voltage converted by the output current of the boost power circuit with the voltage value converted by the overcurrent threshold, and outputs a high level to the second input terminal of the AND gate when it exceeds;

The fifth comparator compares the voltage converted by the output current of the boost power circuit with the voltage value converted by the current limiting threshold, and outputs a high level to the protection circuit when it exceeds; the protection circuit sends an overcurrent signal to the control PWM controller to maintain the current PWM The duty cycle does not change until the output current is lower than the current limit threshold;

The output end of the AND gate is connected to a protection circuit. When the AND gate outputs a high level, the output power tube of the boost power circuit is turned off and power supply is stopped.

Preferably, the current limit threshold is the current required when the load is in the maximum set power state; the overcurrent threshold is 1.2 times the current required when the load is in the maximum actual power state; the overvoltage threshold is the standard value of the required output voltage 1.2 times.

Preferably, one set of switch contacts of the power-on switch is used to control power-on, and the other set of switch contacts is connected to the ground status indicator light to feed back the power-on status to the ground; a set of switch contacts of the power-on switch is used to control the power-on status. The other group of switch contacts is connected to the ground status indicator, and the power transfer is successful to the ground.

Preferably, it also includes monitoring the output voltage and current to the satellite through the output current telemetry terminal and the output voltage telemetry terminal on the ground; if both are within the set range, it is determined that the power supply output of the equipment is in a normal state, and the current equipment is calculated based on the current telemetry value. End load power supply; if the voltage is not within the set range, stop outputting voltage to the satellite; if the current is not within the set range, check the power consumption of the satellite load, the satellite has a short circuit and excessive power consumption, or some equipment does not start to work, cause the current to be too small.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention is directly boosted to the satellite load voltage for the first time and then transmitted. After adopting the boosted power supply system, it can meet the requirements of simultaneously supplying power to multiple payload satellite loads, and can save the battery consumption of the payload satellites during the flight of the aircraft, reducing the The design difficulty of the battery of the payload satellite is improved, and the power supply efficiency of the power supply system of the payload satellite is improved.

(2) The present invention also solves the problem of insufficient long-distance high-power power supply capability of the aircraft for the payload satellite by adopting the boosted power supply system, making the design of the long-distance power supply cable simple and the loss on the cable small, improving the power supply efficiency, and at the same time high-power power supply It can also stabilize the bus voltage when the load is suddenly changed, which makes the design of the load secondary power module easier.

(3) Replacing the booster power components in the booster circuit, changing the threshold of the comparator can meet various bus voltage requirements of the satellite, and has good scalability, which opens up space for the booster power supply system of the aircraft.

(4) Compared with the traditional method of cutting off the power supply output once overvoltage or overcurrent occurs, the present invention maximizes the supply of electric energy to the satellite through the combined control of overvoltage and overcurrent, and reduces the loss of the electric energy carried by the satellite itself.

Description of drawings

Fig. 1 is the schematic diagram of the load satellite boost power supply system of the present invention;

Figure 2 is a schematic diagram of a boost power circuit;

Fig. 3 is a schematic diagram of boost PWM control;

Figure 4 is a schematic diagram of the protection principle.

Detailed ways

Figure 1 shows the system scheme of the aircraft of the present invention to supply power to loads such as satellites. The aircraft adopts the solution of battery and boost controller to provide power energy for the payload satellite. The output voltage of the battery is 28V, and the arrow boost controller turns on the relay switch to make the booster work to output 45V voltage, and then output it to the satellite load. Due to the large working power of the satellite load, the boost controller also needs to maintain stable and reliable operation at high power output.

1. Boost technology

The battery converts the stored chemical energy into electrical energy and outputs the voltage. The bus voltage required by the satellite load is 45V higher than the battery bus voltage 28V. The busbar needs to be adjusted and controlled to increase the busbar voltage while maintaining the performance of the busbar. It meets the requirements of normal power supply for payloads such as payload satellites. Although the safety factor of the input and output isolation boost circuit is relatively high, the isolation transformer has disadvantages such as magnetic leakage and loss, so it is particularly important to be able to stably output high-power non-isolated boost DC/DC modules.

The battery voltage is boosted to a voltage slightly higher than the power supply voltage required by the satellite load. Considering the cable voltage drop of long-term transmission, the higher voltage is in the range of 1 to 3V.

The main considerations in designing a boost circuit are: circuit reliability, circuit conversion efficiency, output bus performance, structure and quality requirements, equipment power density and thermal environment requirements. The reliability of the boost circuit is the primary consideration factor for the aircraft to supply power to loads such as satellites. The design and use of components must meet the first-level derating, and there is no long-term work damage to ensure the reliability of the boost circuit. The high conversion efficiency of the boost circuit is a necessary factor in the design of high-power power supply. Improving the conversion efficiency can effectively reduce the capacity of the battery and improve the effective power of the system; at the same time, improving the conversion efficiency can also reduce the size and quality of the equipment structure and improve the effectiveness of the aircraft. load weight.

Compare the existing boost circuit valley-filling phase-shift full bridge, Super boost and Weinberg converters, see Table 1 for details.

Table 1 Performance comparison of three boost topologies

It can be seen from the comparison that the above three topologies are compared. In order to reduce the volume and weight of the converter, improve the efficiency of the converter, and make it easier to realize circuit control, and to meet the principle of maximum high reliability, the Weinberg boost circuit is selected. Way. The Weinberg boost circuit can achieve a high-efficiency output of more than 95%. The low-voltage drive of the power tube simplifies the switching loss of the gate drive circuit and the power tube, and the output current is continuous. The stress of the power tube is small, which can meet the reliability requirements of the system boost circuit.

The Weinberg boost circuit adopts a push-pull improved circuit structure. When the two MOSFETs are turned on alternately, the energy storage inductor is charged, and the push-pull transformer outputs energy to the secondary side. When both MOSFETs are turned off, the energy storage inductor outputs energy to the secondary side. After this improved method, compared with the traditional boost circuit structure, in the process of energy storage of the main inductor, there is still current output through the coupling effect of the transformer, so that in a cycle, the output current is continuous, so The output capacitance can be very small, which has obvious advantages for making the push-pull circuit of the boost circuit as a current source.

2. Protection circuit design

The boost power supply system is equipped with a system protection circuit to prevent the back-end load failure from expanding to the aircraft battery, threatening the successful launch of the aircraft. The boost power supply system has two failure modes. One is input overcurrent protection to prevent the back-end load from being short-circuited, the output current is too large, and the battery rapidly discharges with high current; the other is output overvoltage protection, and the internal boost control loop fails When adjusting the bus voltage, cut off the device output. At the same time, when working normally, the output power of the load is limited, and the non-faulty over-limit high power of the load is limited, so as to protect the battery equipment of the boost power supply system and the thermal environment of the aircraft equipment.

The input overcurrent protection circuit consists of two parts: current sampling and power switch. The input overcurrent protection circuit is located at the input port of the boost control loop. When the internal circuits or components of the boost control loop cause the aircraft battery to output overcurrent, the overcurrent protection circuit automatically cuts off the power switch. The aircraft battery discharge current signal is amplified by the operational amplifier and sent to the non-inverting terminal of the hysteresis comparator. When the aircraft battery discharge current exceeds the set value, the output voltage of the hysteresis comparator will be reversed, and a signal to turn off the power switch will be generated. The control loop is disconnected from the aircraft battery.

The output overvoltage protection circuit cuts off the booster regulator when the busbar is overvoltage, which causes the overvoltage. The reason for the busbar overvoltage is that the output of the booster control circuit is not controlled by the error amplifier circuit. After the busbar overvoltage protection occurs, firstly determine the booster unit that caused the overvoltage fault and turn it off.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Figure 1 is a schematic diagram of the design principle of the boost power supply system. The boost power supply system includes a battery part, a command switch control part, an input filter network, a boost circuit (including a boost power circuit, a boost control PWM loop and a protection circuit), an output filter network and a telemetry part. Drive the device to power on and transfer power through control commands. After receiving the power-on command, the power-on switch is closed, the other group of switch contacts of the power-on switch is connected to the ground status indicator, and the power-on status is fed back to the ground. The telemetry terminal can monitor whether the output voltage of the battery is normal in real time, and then can judge whether the power-on status of the equipment is normal; after receiving the power transfer command, the power transfer switch is closed, and the other group of switch contacts of the power transfer switch is connected to the ground status indicator, and the ground status indicator is connected to the ground. Feedback transfer is successful, and output 45V voltage to the satellite load at the same time; the ground monitors the output voltage and current to the satellite through the output current telemetry terminal and the output voltage telemetry terminal, and if they are within the set range, determine the power supply output of the equipment and the status of the power transfer of the equipment Normal, the current power supply power for the back-end load can be calculated through the current telemetry value. If the voltage is not within the set range, it will stop outputting voltage to the satellite. If the current is not within the set range, check the power consumption of the satellite load. There may be a short circuit in the satellite. When the power consumption is too large, or some equipment does not start to work, the current is too small.

The main function of the input filter network is to filter out the spatial interference on the cable and avoid large fluctuations in the signal entering the boost circuit. The inductor-capacitor filter circuit is used to ensure continuous input current and limit battery discharge ripple current.

The output filter network adopts high-frequency filter capacitor and low-frequency filter capacitor circuit. The main function is to stabilize the output voltage, filter the peak signal of the switching power supply, and at the same time improve the characteristic index of the load bus after long-distance power supply, so that the back-end load bus has less ripple , the peak is smaller.

The main components of the boost circuit include:

1) Boost power circuit

The boost power circuit adopts the Weinberg boost push-pull circuit, which is mainly composed of core components such as power tubes, transformers, inductors, and surrounding auxiliary isolation diodes, capacitors and resistors, as shown in Figure 2. The voltage is boosted by 45V through the transformer M2. The power tubes Q1 and Q2 are turned on, and the diodes D2 and D1 are turned on respectively under the action of the coupling transformer M1. At this time, the freewheeling diode D3 is turned off; the power tube is turned off, and the freewheeling diode D3 is turned on at this time to stabilize the voltage. output. The boost power circuit works in an asynchronous 100kHz state to boost the battery output voltage and control the output current.

2) Boost control PWM loop

The boost control PWM loop takes the output voltage and output current of the boost power circuit as the sampling voltage and sampling current, see Figure 3. The load load change causes the fluctuation of the sampling voltage, which is compared with the reference voltage 1 through the error amplifier comparator, and the output voltage is compared with the control reference voltage 2, and then the PWM duty cycle is controlled. The sampling current is compared with the control reference voltage 2 through a two-stage operational amplifier, and a control signal is output. The addition of current control can adjust the small changes of the load current and stabilize the bus output voltage. When the power supply voltage to the load increases and is higher than the reference voltage 1, the comparator 1 outputs a high level, which is greater than the reference voltage 2, so the comparator 2 outputs a low level, and the PWM controller reduces the PWM duty ratio, reducing the output voltage; using the reverse proportional adjustment circuit to sample the load current, when the current provided to the load decreases, the reverse proportional amplification and the converted voltage increase the comparison voltage, which is higher than the reference voltage After 2, the comparator 2 outputs a low level, and the PWM controller reduces the PWM duty cycle and reduces the output voltage. That is, when the power supply voltage to the load exceeds the set threshold (45V) or the load current is less than the set threshold (3A), the PWM duty cycle is reduced and the output voltage is reduced; otherwise, when the power supply voltage to the load is lower than the set threshold ( 45V) or when the load current is greater than the set threshold (3A), increase the PWM duty cycle and increase the output voltage.

3) Protection circuit

Figure 4 is a schematic diagram of the design principle of the protection circuit. The input overcurrent and output overvoltage protection circuits are composed of three comparators and a protection locking circuit. The input overcurrent signal comes from current sampling and is amplified by an operational amplifier.

The overvoltage signal is derived from the transformed value of the output voltage of the booster. When the output voltage is normal, the output of the comparator 3 is a low level, and when the overvoltage is present, the output of the comparator 3 is a high level. The current limit signal corresponds to the booster output current of 22.5A, and the overcurrent signal threshold corresponds to the booster output current of 30A.

When the current is greater than 22.5A, the output of the comparator 5 is turned to a high level, and the protection circuit controls the PWM controller to keep the current PWM duty cycle unchanged until the current returns to normal.

When the internal circuits or components of the booster cause the battery output overcurrent to exceed 30A, the overcurrent signal is greater than the overcurrent signal threshold, the comparator 4 outputs a high level, and the overcurrent signal and the overvoltage signal are combined and then output to the protection circuit. If the overcurrent signal and the overvoltage signal are both high, the cut-off protection is activated through the protection circuit, the power tubes Q1 and Q2 are turned off, and the fault booster stops working. The circuit unlocking at this time requires the battery input relay to be de-energized and then re-energized.

If only overvoltage or overcurrent occurs, the output can be recovered by itself through the PWM control in Figure 2, and the protection will not be activated.

The power supply of the aircraft to the payload satellite is limited by the distance between the installation position of the instrument and the electrical equipment of the payload satellite and the power supply to two satellites at the same time. The power of the entire payload satellite can reach more than 600 watts during the flight of the vehicle. If the battery is used for direct power supply, the line The cable design is very large, and the loss on the cable is large, which is not conducive to the optimization of the aircraft electrical system. The aircraft satellite power supply system adopts the invention to increase the power supply voltage not only to reduce the loss and improve the efficiency, but also to directly supply power to the payload of the satellite, reduce the working time of the payload and prolong the on-orbit life of the payload.

The above is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention.

Contents that are not described in detail in the specification of the present invention belong to the well-known technology of those skilled in the art.

Claims (7)

1. a high-power and high-stability boost power supply system is characterized in that comprising: a battery, a command switch control circuit, a boost power circuit, a boost control PWM circuit and a protection circuit; After the command switch control circuit receives the power-on command, it controls the power-on switch to close, and the boost power circuit boosts the battery voltage to the required output voltage; after the command switch control circuit receives the power-on command, it controls the power-on switch. The electrical switch is closed, and the boost power circuit supplies power to the load; The boost control PWM loop is used to reduce the PWM duty cycle and reduce the output voltage when the power supply voltage to the load exceeds the set first voltage threshold or the load current is less than the set first output current threshold; otherwise, the PWM duty cycle is increased. ratio, increase the output voltage; The protection circuit stops power supply when the output voltage is over-voltage and the output current is over-current; when the output current exceeds the current limiting threshold, the boost control PWM loop is controlled to keep the current PWM duty cycle unchanged; The boost power circuit adopts a Weinberg boost push-pull circuit; The boosting power circuit boosts the battery voltage through the transformer M2; when the power tubes Q1 and Q2 are turned on, the diodes D2 and D1 are caused to conduct respectively under the action of the coupling transformer M1, and the boosted voltage is output. When the freewheeling diode D3 of the transformer M2 is turned off; when the power tubes Q1 and Q2 are turned off, the freewheeling diode D3 is turned on to maintain the voltage output; The boost control PWM loop includes a first comparator, a second comparator and a PWM controller; The first comparator compares the output voltage of the boost power circuit with the first voltage threshold, if it is higher than the first voltage threshold, it outputs a high level, otherwise it outputs a low level; the negative input end of the second comparator is connected to the same time. Input the output level of the first comparator and the voltage converted by the inversely proportionally adjusted load current, if the first comparator outputs a high level, or the load current is less than the first output current threshold, the second comparator outputs a low level To the PWM controller, the PWM controller reduces the PWM duty cycle and reduces the output voltage; on the contrary, increases the PWM duty cycle and increases the output voltage. 2. The high-power and high-stability boost power supply system as claimed in claim 1, further comprising an input filter network and an output filter network; the input filter network is used to filter out the interference on the battery power supply bus; the output filter network It includes a high-frequency filter capacitor circuit and a low-frequency filter capacitor circuit to stabilize the output voltage of the boost power circuit. 3. The high-power and high-stability boost power supply system according to claim 1, wherein the first voltage threshold is a standard value of a required output voltage, and the first output current threshold is a required value when the load is in an average power state. current. 4. The high-power and high-stability boost power supply system according to claim 1, wherein the protection circuit comprises a third comparator, a fourth comparator, a fifth comparator and an AND gate; The third comparator compares the output voltage of the boost power circuit with the overvoltage threshold, and outputs a high level to the first input end of the AND gate when the overvoltage threshold is exceeded; The fourth comparator compares the voltage converted by the output current of the boost power circuit with the voltage value converted by the overcurrent threshold, and outputs a high level to the second input terminal of the AND gate when it exceeds; The fifth comparator compares the voltage converted by the output current of the boost power circuit with the voltage value converted by the current limiting threshold, and outputs a high level to the protection circuit when it exceeds; the protection circuit sends an overcurrent signal to the control PWM controller to maintain the current PWM The duty cycle does not change until the output current is lower than the current limit threshold; The output end of the AND gate is connected to a protection circuit. When the AND gate outputs a high level, the output power tube of the boost power circuit is turned off and power supply is stopped. 5. The high-power and high-stability boost power supply system according to claim 1, wherein the current-limiting threshold is the current required when the load is in a state of maximum set power; the over-current threshold is that the load is in a state of maximum actual power 1.2 times the required current; the overvoltage threshold is 1.2 times the standard value of the required output voltage. 6. The high-power and high-stability boost power supply system as claimed in claim 1, wherein one group of switch contacts of the power-on switch is used to control power-on, and the other group of switch contacts is connected to the ground status indicator light, Feedback the power-on status to the ground; one group of switch contacts of the power-transfer switch is used to control the power-transfer, and the other group of switch contacts is connected to the ground status indicator to feedback to the ground that the power-transfer is successful. 7. The high-power and high-stability boost power supply system as claimed in claim 1, further comprising that the ground monitors the output voltage and current to the satellite through the output current telemetry terminal and the output voltage telemetry terminal; If the voltage is not within the set range, it will stop outputting voltage to the satellite; if the current is not within the set range, check the satellite load In terms of electricity consumption, the satellite has a short circuit and excessive electricity consumption, or some equipment does not start to work, resulting in too small current.

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