阅读说明：本技术 电推进旋翼飞行器动力系统及其控制方法 (Electric propulsion rotor craft power system and control method thereof ) 是由 陈方 田沛东 于 2020-05-28 设计创作，主要内容包括：一种电推进旋翼飞行器动力系统及其控制方法,所述的飞行器动力系统包括融合储能系统、无刷直流电机调速器、无刷直流电机、安装在所述无刷直流电机上的螺旋桨、飞控计算机、飞行器惯性传感器、高度传感器以及遥控信号接收器。本发明飞行器动力系统能够预测飞行器功率需求,以达到较好的管理储能系统的功率输出。通过该动力系统控制方法,能够以更低重量的动力系统满足飞行器实时功率需求和功率储备需求,同时,该动力系统控制方法还能延长能源系统使用寿命,使得飞行器安全性、机动性和续航能力提高。(An electric propulsion rotor craft power system and a control method thereof, wherein the craft power system comprises a fusion energy storage system, a brushless direct current motor speed regulator, a brushless direct current motor, a propeller arranged on the brushless direct current motor, a flight control computer, a craft inertial sensor, a height sensor and a remote control signal receiver. The aircraft power system can predict the aircraft power demand so as to achieve better management of the power output of the energy storage system. By the power system control method, the real-time power requirement and the power reserve requirement of the aircraft can be met by the power system with lower weight, and meanwhile, the power system control method can prolong the service life of the energy system, so that the safety, the maneuverability and the cruising ability of the aircraft are improved.)

1. An electrically propelled rotorcraft power system, the power system comprising: the system comprises a fusion energy storage system, a brushless direct current motor speed regulator, a brushless direct current motor, a propeller arranged on the brushless direct current motor, a flight control computer, an aircraft inertia sensor, a height sensor and a remote control signal receiver;

the speed regulator of the brushless direct current motor is composed of a first alternating current inverter, a second alternating current inverter, a third alternating current inverter and a fourth alternating current inverter, the output ends of the aircraft inertial sensor, the height sensor and the remote control signal receiver are connected with the flight control computer, the fusion energy storage system comprises a lithium battery and a super capacitor, the output end of the super capacitor adopts a bidirectional DC/DC exchanger to control the energy flow direction and is connected with the lithium battery in parallel, the output end of a voltage sensor connected with the lithium battery in parallel is connected with the input end of the flight control computer, the output end of a voltage sensor connected with the super capacitor in parallel is connected with the input end of the flight control computer, the positive electrode of the lithium battery is respectively connected with the first alternating current inverter, the second alternating current inverter, the third alternating, The output ends of the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter are correspondingly connected with the first brushless DC motor, the second brushless DC motor, the third brushless DC motor and the fourth brushless DC motor one by one, and the control output end of the flight control computer is respectively connected with the control ends of the bidirectional DC/DC converter, the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter.

2. An electrically propelled rotorcraft power system according to claim 1, wherein the aircraft altitude sensor is an ultrasonic distance sensor or a barometric altimeter.

3. A method of controlling an electric propulsion rotary-wing aircraft power system according to claim 1, characterized in that the method comprises the steps of:

1) aircraft flight pattern recognition and power prediction, including:

①, the flight control computer collects the data of the aircraft inertial sensor and filters the data to obtain the attitude angle of the aircraftTheta, psi, triaxial acceleration a in the aircraft body coordinate system_x，a_y，a_zThree-axis angular velocity omega in aircraft body coordinate system_x，ω_y，ω_zAcquiring the data of the aircraft height sensor and filtering the data to obtain the height information h of the aircraft from the ground;

based on the data of an aircraft inertial sensor, the flight control computer judges the flight speed change mode, the attitude change mode and the altitude change mode of the aircraft;

the flight control computer is combined with aircraft control instruction input to predict whether the aircraft power demand category is low power, instantaneous high power or long-term high power according to a preset weight value;

2) the flight control computer sets the working modes of the lithium battery and the super capacitor in a grading manner according to the power demand categories of the aircraft: the working modes of the lithium battery are divided into 4 levels with preset output power of P1, P2, P3 and P4, P1< P2< P3< P4, the working modes of the super capacitor are divided into 5 modes of disconnection, discharge, slow charge, faster charge and fast charge, SOC is used for representing the charge state of the super capacitor, and the charge state of the hierarchical super capacitor is defined as follows: the upper limit of the primary SOC is H1, the upper limit of the secondary SOC is H2, the lower limit of the primary SOC is L1, the lower limit of the secondary SOC is L2, 0< L2< L1< H1< H2< 100%, and the working modes of the lithium battery and the super capacitor are determined in the following mode:

if the aircraft power demand category is low power consumption:

judging that the SOC is greater than H2, setting the preset output power of the lithium battery to be P1, and switching off the working mode of the super capacitor;

judging that H1< SOC < H2, setting the preset output power of the lithium battery to be P2, and slowly charging the super capacitor in a working mode;

judging that the SOC of L1 is less than H2, setting the preset output power of the lithium battery to be P3, and enabling the super capacitor to be charged quickly in a working mode;

judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and setting the working mode of the super capacitor to be quick charging;

if the aircraft power demand category is instantaneous high power consumption:

judging that the SOC is greater than L2, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging;

judging that the SOC is less than L2, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor;

if the aircraft power demand category is long-term high power consumption:

judging that the SOC is greater than L1, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging;

judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor;

3) setting the output power of the lithium battery and the super capacitor: smoothing the output power of the lithium battery based on a filtering algorithm, and supplementing the lacking power or storing the excessive power by adopting a super capacitor, so that the output fluctuation of the lithium battery is small and is close to the preset output power of the lithium battery in the step 2) while the total power output meets the power requirement of the aircraft;

4) the bidirectional DC/DC exchanger is used for controlling the power output of the super capacitor, and the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter are used for controlling the overall power output of an energy system to drive the first brushless DC motor, the second brushless DC motor, the third brushless DC motor and the fourth brushless DC motor to provide required power for the propeller.

Technical Field

The invention relates to an aircraft, in particular to an electric propulsion rotor aircraft power system and a control method thereof.

Background

The electric engine revolution is in the night, the replacement of the traditional energy form by electric energy is a necessary development direction, and the popularization of electric propulsion breaks through the current traditional airplane and engine manufacturing pattern. The electric propulsion technology has obvious advantages, and the autonomous manned aircraft based on electric propulsion is the technical development direction of urban air traffic solutions. The pure electric drive power system is the core technology of the electric propulsion aircraft.

With the rapid development of new energy fields in recent years, the research on various energy storage units tends to mature, but each energy storage unit has inevitable defects. The lithium battery has the advantages of high energy density, but has the defects of low specific power, short cycle life and the like, so that the energy release capacity of the lithium battery is poor; the super capacitor has the advantage of high power density, but has obvious disadvantages in terms of specific energy parameters, so that the energy storage performance is poor.

The main bottleneck of the application of the electric propulsion system on the aircraft at the present stage is that the power requirements of the aircraft in different flight states are greatly different, and the traditional power system based on a single energy storage element cannot simultaneously give consideration to high output efficiency and the power requirements of the aircraft for rapidly responding to rapid change. For example, the power system based on the lithium battery is widely adopted in the power system of the current electric propulsion aircraft, and has the defects of low response speed, poor power matching effect, high battery life loss and the like in the face of large changes of power requirements of different flight modes of the aircraft.

Disclosure of Invention

The invention aims to provide an electric propulsion rotor craft power system and a control method thereof. The high-efficiency output of the power system is realized on the basis of meeting the quick response to the power demand of the aircraft. The core of the invention is therefore the matching of the aircraft power requirements and the energy storage system power output. Through the power system control method based on the flight mode identification of the aircraft, the power system of the aircraft can predict the power requirement of the aircraft so as to achieve the purpose of better managing the power output of the energy storage system.

By the power system control method, the real-time power requirement and the power reserve requirement of the aircraft can be met by the power system with lower weight, and meanwhile, the power system control method can prolong the service life of the energy system, so that the safety, the maneuverability and the cruising ability of the aircraft are improved.

The technical solution of the invention is as follows:

an electric propulsion rotor craft power system is characterized in that the craft power system comprises a fusion energy storage system, a brushless direct current motor speed regulator, a brushless direct current motor, a propeller arranged on the brushless direct current motor, a flight control computer, a craft inertial sensor, a height sensor and a remote control signal receiver;

the speed regulator of the brushless direct current motor is composed of a first alternating current inverter, a second alternating current inverter, a third alternating current inverter and a fourth alternating current inverter, the output ends of the aircraft inertial sensor, the height sensor and the remote control signal receiver are connected with the flight control computer, the fusion energy storage system comprises a lithium battery and a super capacitor, the output end of the super capacitor adopts a bidirectional DC/DC exchanger to control the energy flow direction and is connected with the lithium battery in parallel, the output end of a voltage sensor connected with the lithium battery in parallel is connected with the input end of the flight control computer, the output end of a voltage sensor connected with the super capacitor in parallel is connected with the input end of the flight control computer, the positive electrode of the lithium battery is respectively connected with the first alternating current inverter, the second alternating current inverter, the third alternating, The output ends of the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter are correspondingly connected with the first brushless DC motor, the second brushless DC motor, the third brushless DC motor and the fourth brushless DC motor one by one, and the control output end of the flight control computer is respectively connected with the control ends of the bidirectional DC/DC converter, the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter.

The aircraft altitude sensor is an ultrasonic distance sensor or a barometric altimeter.

The control method of the power system of the electric propulsion rotor aircraft is characterized by comprising the following steps:

1) aircraft flight pattern recognition and power prediction, including:

①, the flight control computer collects the data of the aircraft inertial sensor and filters the data to obtain the attitude angle of the aircraft

Theta, psi, triaxial acceleration a in the aircraft body coordinate system_x，a_y，a_zThree-axis angular velocity omega in aircraft body coordinate system_x，ω_y，ω_zAcquiring the data of the aircraft height sensor and filtering the data to obtain the height information h of the aircraft from the ground;

based on the data of an aircraft inertial sensor, the flight control computer judges the flight speed change mode, the attitude change mode and the altitude change mode of the aircraft;

the flight control computer is combined with aircraft control instruction input to predict whether the aircraft power demand category is low power, instantaneous high power or long-term high power according to a preset weight value;

2) the flight control computer sets the working modes of the lithium battery and the super capacitor in a grading manner according to the power demand categories of the aircraft: the working modes of the lithium battery are divided into 4 levels with preset output power of P1, P2, P3 and P4, P1< P2< P3< P4, the working modes of the super capacitor are divided into 5 modes of disconnection, discharge, slow charge, faster charge and fast charge, SOC is used for representing the charge state of the super capacitor, and the charge state of the hierarchical super capacitor is defined as follows: the upper limit of the primary SOC is H1, the upper limit of the secondary SOC is H2, the lower limit of the primary SOC is L1, the lower limit of the secondary SOC is L2, 0< L2< L1< H1< H2< 100%, and the working modes of the lithium battery and the super capacitor are determined in the following mode:

if the aircraft power demand category is low power consumption:

judging that the SOC is greater than H2, setting the preset output power of the lithium battery to be P1, and switching off the working mode of the super capacitor;

judging that H1< SOC < H2, setting the preset output power of the lithium battery to be P2, and slowly charging the super capacitor in a working mode;

judging that the SOC of L1 is less than H2, setting the preset output power of the lithium battery to be P3, and enabling the super capacitor to be charged quickly in a working mode;

judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and setting the working mode of the super capacitor to be quick charging;

if the aircraft power demand category is instantaneous high power consumption:

judging that the SOC is greater than L2, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging;

judging that the SOC is less than L2, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor;

if the aircraft power demand category is long-term high power consumption:

judging that the SOC is greater than L1, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging;

judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor;

3) setting the output power of the lithium battery and the super capacitor: smoothing the output power of the lithium battery based on a filtering algorithm, and supplementing the lacking power or storing the excessive power by adopting a super capacitor, so that the output fluctuation of the lithium battery is small and is close to the preset output power of the lithium battery in the step 2) while the total power output meets the power requirement of the aircraft;

4) the bidirectional DC/DC exchanger is used for controlling the power output of the super capacitor, and the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter are used for controlling the overall power output of an energy system to drive the first brushless DC motor, the second brushless DC motor, the third brushless DC motor and the fourth brushless DC motor to provide required power for the propeller.

The invention has the following technical effects:

1. the invention realizes high-efficiency output of the power system on the basis of meeting the quick response to the power demand of the aircraft. The core of the invention is therefore the matching of the aircraft power requirements and the energy storage system power output. Through the power system control method based on the flight mode identification of the aircraft, the power system of the aircraft can predict the power requirement of the aircraft so as to achieve the purpose of better managing the power output of the energy storage system.

2. By the power system control method, the real-time power requirement and the power reserve requirement of the aircraft can be met by the power system with lower weight, and meanwhile, the power system control method can prolong the service life of the energy system, so that the safety, the maneuverability and the cruising ability of the aircraft are improved.

Drawings

FIG. 1 is a schematic diagram of the circuit configuration and control signals of the power system of the present invention;

FIG. 2 is a flow chart of the operating principle of the control method of the power system according to the present invention;

FIG. 3 is a schematic flow chart of a method for identifying patterns of an aircraft according to the present invention;

FIG. 4 is a schematic flow chart of a method for setting the working mode of the lithium battery and the super capacitor according to the present invention;

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

This embodiment is described below with reference to fig. 1 to 4. Referring initially to fig. 1, it can be seen that the present invention is an electric propulsion rotorcraft power system based on flight mode identification, comprising: the system comprises a fusion energy storage system, a brushless direct current motor speed regulator, a brushless direct current motor, a propeller arranged on the brushless direct current motor, a flight control computer, an aircraft inertia sensor, a height sensor and a remote control signal receiver; the speed regulator of the brushless direct current motor is composed of a first alternating current inverter, a second alternating current inverter, a third alternating current inverter and a fourth alternating current inverter, the output ends of the aircraft inertial sensor, the height sensor and the remote control signal receiver are connected with the flight control computer, the fusion energy storage system comprises a lithium battery and a super capacitor, the output end of the super capacitor adopts a bidirectional DC/DC exchanger to control the energy flow direction and is connected with the lithium battery in parallel, the output end of a voltage sensor connected with the lithium battery in parallel is connected with the input end of the flight control computer, the output end of a voltage sensor connected with the super capacitor in parallel is connected with the input end of the flight control computer, the positive electrode of the lithium battery is respectively connected with the first alternating current inverter, the second alternating current inverter, the third alternating, The positive pole of the input end of the fourth AC inverter is connected, the negative pole of the lithium battery is respectively connected with the negative poles of the input ends of the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter, the output ends of the first AC inverter, the second AC inverter, the third AC inverter and the fourth AC inverter are respectively connected with the first brushless DC motor, the second brushless DC motor, the third brushless DC motor and the fourth brushless DC motor, wherein the three-phase joint of the output end of the AC inverter is respectively connected with the three-phase joint of the brushless DC motor, and the joints do not distinguish a specific connection sequence. The rotation direction of the brushless direct current motor can be changed by exchanging the connection of any two-phase joint, and the control output end of the flight control computer is respectively connected with the control ends of the bidirectional DC/DC converter, the first alternating current inverter, the second alternating current inverter, the third alternating current inverter and the fourth alternating current inverter.

The aircraft altitude sensor is an ultrasonic distance sensor or a barometric altimeter.

The implementation method adopts the working principle of the power system control method shown in figure 2, namely:

step 1, recognizing flight modes of aircrafts and predicting power;

step 2, identifying the charge states of the lithium battery and the super capacitor;

step 3, setting working modes of the lithium battery and the super capacitor;

and 4, setting the output power of the lithium battery and the super capacitor.

And 5, controlling the power output of the super capacitor through the bidirectional DC/DC exchanger, controlling the overall power output of the energy system through the alternating current inverter, driving the brushless direct current motor, and driving the propeller to provide required power.

Further, in the present implementation method, the aircraft flight pattern recognition and the power prediction in step 1 are implemented by the aircraft pattern recognition method principle shown in fig. 3. The method for recognizing the aircraft mode comprises the following principle steps:

the flight control computer in the step 1-1 acquires and filters the data of the aircraft inertial sensor to obtain the attitude angle of the aircraftTheta, psi, triaxial acceleration a in the aircraft body coordinate system_x，a_y，a_zThree-axis angular velocity omega in aircraft body coordinate system_x，ω_y，ω_zAcquiring data of an aircraft altitude sensor (which can be an ultrasonic distance sensor or a barometric altimeter) and filtering to obtain the altitude h of the aircraft to the ground;

and 1-2, judging the flight speed change mode of the aircraft. The implementation method adopts a nonlinear autoregressive time series neural network, predicts the power requirement of the next time step through a neural network function generated by the network, and identifies the power requirement mode in the flight state. The nonlinear autoregressive time series neural network is obtained through computer simulation and aircraft flight test data training. The attitude angle of the aircraft in the step 1-1 can be utilized through the nonlinear autoregressive time series neural network functionTheta, psi, triaxial acceleration a in the aircraft body coordinate system_x，a_y，a_zThree-axis angular velocity omega in aircraft body coordinate system_x，ω_y，ω_zAnd angular acceleration p, q and r and the data of the height h of the aircraft from the ground are used for solving the time sequence of the flight speed change mode, the attitude change mode and the altitude change mode of the aircraft.

Steps 1-3 identify an aircraft power demand class. The power demand classes are: low power, instantaneous high power, long-term high power. The implementation method adopts a fuzzy inference algorithm to identify the type of the aircraft power demand in the flight state. And (3) inputting a remote control command of the aircraft as a fuzzy input variable by using the time sequence of the flight speed change mode, the attitude change mode and the altitude change mode of the aircraft in the step 1-2. Wherein the flight speed variation pattern has three membership functions: stationary (STA), Deceleration (DEC) and Acceleration (ACC); the altitude variation pattern has five membership functions: high speed descent (MDEC), Descent (DEC), constant Height (HAV), ascent (CLI) and high speed ascent (MCLI); the attitude change pattern has three membership functions: steady (STA), Rotational (ROT), high speed rotational (MROT). The output variables are aircraft power demand classes, ranging from [0,1], with three membership functions: LOW power (LOW), instantaneous high power (IH), long term high power (LH); the aircraft remote control command input has two membership functions: LOW (LOW) and HIGH (HIGH). And on the basis of summarizing expert experience, establishing a fuzzy control rule base. The identification of the aircraft power demand category based on flight speed change mode, attitude change mode, altitude change mode time sequence and aircraft remote control command input is realized through fuzzy logic operation.

Further, in the implementation method, the setting of the working mode of the lithium battery and the super capacitor in step 3 is implemented by the principle of the setting method of the working mode of the lithium battery and the super capacitor shown in fig. 4. The method for setting the working mode of the lithium battery and the super capacitor comprises the following steps:

and according to the category of the power requirement of the aircraft, the working modes of the lithium battery and the super capacitor are set in a grading manner. The working modes of the lithium battery are divided into 4 levels (P1< P2< P3< P4) with preset output power P1, P2, P3 and P4, and the working modes of the super capacitor are divided into 5 modes of disconnection, discharge, slow charge, faster charge and fast charge. Representing the charge state of the super capacitor by SOC, and defining the charge state of the hierarchical super capacitor: the first-level SOC upper limit H1, the second-level SOC upper limit H2, the first-level SOC lower limit L1, and the second-level SOC lower limit L2((0< L2< L1< H1< H2< 100%), the specific determination method is as follows:

if the type of the aircraft power demand is low power consumption, judging that the SOC is more than H2, setting the preset output power of the lithium battery to be P1, and switching off the working mode of the super capacitor; judging that H1< SOC < H2, setting the preset output power of the lithium battery to be P2, and slowly charging the super capacitor in a working mode; judging that the SOC of L1 is less than H2, setting the preset output power of the lithium battery to be P3, and enabling the super capacitor to be charged quickly in a working mode; and judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and enabling the working mode of the super capacitor to be rapid charging.

If the type of the aircraft power demand is instantaneous high power consumption, judging that the SOC is greater than L2, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging; and judging that the SOC is less than L2, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor.

If the type of the aircraft power demand is long-term high power consumption, judging that the SOC is greater than L1, setting the preset output power of the lithium battery to be P3, and setting the working mode of the super capacitor to be discharging; and judging that the SOC is less than L1, setting the preset output power of the lithium battery to be P4, and switching off the working mode of the super capacitor.

According to a fourth aspect of the present invention, there is provided a method for setting output power of a lithium battery and a super capacitor, the method comprising: the output power of the lithium battery is smooth based on a filtering algorithm, and the super capacitor is adopted to complement the lacking power or store the excessive power, so that the output fluctuation of the lithium battery is small and is close to the preset output power of the lithium battery in claim 3 when the total power output meets the power requirement of an aircraft.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.