Electric or hybrid propulsion system and method for compensating for oscillations in the current oscillations
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SAFRAN ELECTRICAL & POWER
- Filing Date
- 2024-11-08
- Publication Date
- 2026-06-02
Smart Images
Figure CN122139284A_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to the field of electric motors or hybrid power engines. It advantageously finds applications in aviation propulsion systems. Background Technology
[0002] With the increasing demand for intra- and inter-city freight or passenger transport, the field of electric or hybrid propulsion in aviation is rapidly expanding. Aircraft suitable for such propulsion include, in particular, vertical take-off and landing (VTOL) aircraft; short take-off and landing (STOL) aircraft; and some conventional take-off and landing (CTOL) aircraft.
[0003] Aviation electric or hybrid propulsion systems typically include one or more motors powered by a direct current (DC) voltage source. A DC voltage source is a high-voltage direct current (HVDC) network. For example, a DC voltage source may include a battery, a power distribution network, or a fuel cell.
[0004] A major issue with electric propulsion systems is the mass of their various components, particularly the mass of the onboard batteries. Unlike thermal propulsion systems, whose mass decreases during flight due to fuel consumption, the batteries in electric propulsion systems remain essentially constant throughout flight, regardless of their state of charge. Furthermore, some electric or hybrid-powered aircraft—particularly VTOL and CTOL—are designed to carry at most a few passengers, meaning the onboard propulsion system can account for a significant percentage of the aircraft's total mass.
[0005] One solution envisioned in the prior art for minimizing battery mass is to provide a single DC voltage source; multiple power electronic components are connected in parallel to this voltage source via power harnesses grouped together with electrical conductors that deliver energy to each power electronic component. The DC voltage source, as defined herein, can specifically include a battery, a fuel cell, or an HVDC distribution network (e.g., in the form of an HVDC bus), to which the power electronic components are connected. Each power electronic component ensures the transfer of electrical energy from the DC voltage source to the stator windings of the motor. The power electronic components also ensure the conversion of the electrical energy supplied by the voltage source so that it is transmitted to the motor in a waveform suitable for the motor's architecture—in this case, the term power converter is used. If the motor is powered by AC, the power electronic components can also be inverters.
[0006] Each power converter outputs multiphase power, such as three-phase power, applied to the motor stator windings.
[0007] However, a drawback of the architecture is that load differences exist at the input of different power converters due to differences in power components, different measuring sensors used to control and regulate each motor, and / or different stator windings of each motor, or different lengths of power harnesses that ensure current transfer between the DC voltage source and the power components.
[0008] This load difference leads to the initiation of so-called "rotating" currents, which are separate from the main current flowing between the current source and the power components. These rotating currents correspond to the oscillating exchange of electrical power between the power electronic components via the DC power harness due to the aforementioned load imbalance. These currents have high-frequency harmonics, which cause fatigue in the power electronics, further leading to charge / discharge cycles in the constituent elements of capacitive power electronics, and more generally, further causing thermal heating of the power electronics, thus jeopardizing their reliability. If the propulsion system includes a monitoring system for an HVDC network or bus, these currents can also be identified by the monitoring system as a faulty operation of the bus. Therefore, if there is a mechanism that shuts down or reduces the power intended to function when an operational fault is detected on the bus, this mechanism may be erroneously activated when rotating currents are detected, resulting in partial or total loss of mechanical torque output from the motor. The unpredictability of these currents also means that they cause unforeseen wear on power components, thus putting the reliability of the propulsion system at risk.
[0009] One solution provided in the prior art to mitigate the consequences of rotating current is to add passive damping devices to the power harness at the input of each power converter. However, these damping devices include capacitors and windings, and thus increase the mass of the propulsion system, especially when the system includes several power components connected to a DC voltage source. The flight autonomy of the aircraft, or the load that the aircraft can transport, is adversely affected. Furthermore, the dimensions of these damping devices must be specifically designed for each motor to account for the variations that occur within the machine. Summary of the Invention
[0010] One objective is to reduce wear on components in electric or hybrid propulsion systems and increase their reliability.
[0011] Another objective is to propose an electric or hybrid propulsion system that includes a DC voltage source, which is capable of minimizing the rotational current between different power electronic components connected in parallel with the DC voltage source.
[0012] Another objective is to propose an electric or hybrid propulsion system as mentioned in the preceding paragraphs, and this system also has a limited total mass.
[0013] Another objective is to enable optimal compensation of rotating currents across a wide variety of propulsion system topologies.
[0014] Climate change is a major concern for numerous legislative and regulatory bodies around the world. States have implemented, are implementing, and will implement various restrictions on carbon emissions. In particular, a stringent standard applies to both new and currently operating aircraft, meaning that technological solutions must be found to comply with existing regulations. For several years, the civil aviation industry has been taking action to contribute to addressing climate change.
[0015] Efforts in technological research have resulted in significant improvements in the environmental performance of the aircraft. The applicant has considered factors affecting all stages of design and development to obtain more environmentally friendly, energy-intensive aerospace components and products with moderate environmental impact in their integration and use in civil aviation, and with the aim of improving the energy efficiency of the aircraft.
[0016] Therefore, the applicant has been working to reduce its climate impact by using various methods and applications of clean development and manufacturing processes to reduce greenhouse gas emissions to the lowest possible level and reduce the environmental footprint of its operations.
[0017] Therefore, this ongoing research and development simultaneously focuses on next-generation aircraft engines, particularly reducing aircraft weight through the use of materials and lighter onboard equipment, developing the use of electrical technologies to ensure propulsion, and aircraft biofuels as an essential complement to technological progress.
[0018] Therefore, this invention is the result of technical research that focuses on significantly improving aircraft performance, thereby helping to reduce the environmental impact of aircraft.
[0019] In this regard, the first aspect proposes an electric or hybrid propulsion system for an aircraft, comprising: -DC voltage bus - At least two power electronic components connected in parallel with the DC voltage bus - A motor controller, the motor controller including a sensor (8) configured to measure electrical parameters representing at least one of the power electronic components, the measured electrical parameters specifically including the current intensity flowing through the DC voltage bus and / or the voltage across the terminals of the DC voltage bus, Each power electronic component is electrically connected to a separate stator winding, and each stator winding is housed within the motor. The motor is configured to convert electrical energy transmitted to the motor via a DC voltage bus through power electronic components into mechanical torque to provide thrust to the aircraft. The propulsion system includes an active compensation system for at least one power electronic component, which is configured to attenuate oscillating current flowing between at least one power electronic component and other power electronic components via a DC voltage bus based on measured electrical parameters.
[0020] Therefore, by attenuating the oscillating currents between power electronic components based on measurements obtained from sensors housed in the motor controller, these currents can be minimized without complicating the propulsion system. There is no need to add extra components specifically designed for this attenuation to the propulsion system (which would result in a subsequent increase in mass). This reduces fatigue on the power electronic components and increases their reliability, as well as the reliability of the system itself, without increasing the system's mass or cost.
[0021] This active compensation takes into account the propulsion system's topology (i.e., the arrangement of wiring harnesses, power electronics, and motors), and thus allows for optimal compensation as a function of that topology, unlike other compensation systems (e.g., dampers located at the input of the power converter), which are optimal only for the specific topology of the propulsion system.
[0022] In one embodiment, the mechanical torque generated by the motor is configured to drive the propeller directly or by means of a reduction gear system.
[0023] In one embodiment, the heat engine is directly connected to the propeller or connected to the propeller by means of a reduction gear system, and the heat engine is configured to generate additional mechanical torque for driving the propeller in addition to the mechanical torque generated by the motor.
[0024] In one embodiment, the motor is a permanent magnet synchronous type.
[0025] In one embodiment, a compensation system for at least one power electronic component includes: - A bandpass filter configured to generate an intermediate oscillation signal by resetting the average value of a first parameter, the first parameter being selected from the voltage at the terminals of the bus and the strength of the current flowing through the bus, and - A PID controller or RST controller configured to receive an intermediate oscillation signal and transmit an oscillation DC setpoint with a frequency substantially equal to the frequency of the intermediate oscillation signal, the oscillation DC setpoint including a phase shift relative to the intermediate oscillation signal, the phase shift being configured to dampen the intermediate oscillation signal.
[0026] In one embodiment, the propulsion system includes: - First DC voltage bus -Second DC voltage bus, - Four power electronic components, two of which are connected in parallel with the first DC voltage bus, and two of which are connected in parallel with the second DC voltage bus. The motor includes four stator windings, each of which is powered by one of four power electronic components. The two DC voltage buses are not electrically connected. In one embodiment, the propulsion system includes: - First DC voltage bus -Second DC voltage bus, - Four power electronic components, two of which are connected in parallel with a first DC voltage bus, and two of which are connected in parallel with a second DC voltage bus. - Two motors, each motor including two stator windings, the first stator winding of each motor being powered by a power electronic component connected to a first DC voltage bus, and the second stator winding of each motor being powered by a power electronic component connected to a second DC voltage bus. The two DC voltage buses are not electrically connected.
[0027] Another aspect of this disclosure relates to a method for compensating for an oscillating current flowing in a propulsion system as described above, the oscillating current flowing between power electronic components via a DC voltage bus, the compensation method comprising: - Obtain current or voltage measurements through sensors, and - The oscillating current is decayed based on the obtained measurements.
[0028] In one implementation of the invention, the measured electrical parameters include a first parameter selected from the current intensity flowing through the bus and the voltage at the bus terminals. Obtaining the measurement value includes measuring the intensity of the oscillating current, and attenuation includes the following sequential steps: a. Obtain the intermediate oscillation signal by resetting the average value of the first parameter. b. Transmitting an oscillation DC setpoint by applying a reverse oscillation with a frequency substantially equal to the frequency of the intermediate oscillation signal, the oscillation DC setpoint including a phase shift relative to the intermediate oscillation signal, the phase shift being configured to dampen the intermediate oscillation signal.
[0029] Another aspect of this disclosure relates to an aircraft that includes the propulsion system as described above. Attached Figure Description
[0030] Other features, purposes, and advantages will become apparent from the following description, which is merely illustrative and non-limiting, and will be read in conjunction with the accompanying drawings, in which: Figure 1 An electric or hybrid propulsion system in the first aspect of this disclosure is schematically shown.
[0031] Figure 2A An electric or hybrid propulsion system with power redundancy is schematically illustrated in one aspect of this disclosure.
[0032] Figure 2B Another electric or hybrid propulsion system in one aspect of this disclosure is schematically shown.
[0033] Figure 3 A method for compensating for oscillating currents flowing in an electric or hybrid propulsion system is illustrated schematically in the second aspect.
[0034] Figure 4 This is a functional diagram illustrating a known vector control method for motors in the prior art.
[0035] Figure 5 This is a functional diagram illustrating a vector control method for an electric or hybrid propulsion system according to the first aspect.
[0036] Figure 6 This is a Bode plot showing the frequency response of the propulsion system according to the first aspect to different lengths of the power input harness of the propulsion system.
[0037] Figure 7A The time trends of current and voltage at the DC voltage bus of the propulsion system are shown after applying the method according to the second aspect.
[0038] Figure 7B The time trend of mechanical torque generated by the electric or hybrid propulsion system after applying the method according to the second aspect is shown.
[0039] Figure 7C Harmonic analysis of the AC current on the DC voltage bus of the propulsion system is shown after applying the method according to the second aspect.
[0040] Figure 8 An aircraft comprising an electric or hybrid propulsion system, according to the first aspect, is schematically shown.
[0041] In all the accompanying drawings, similar elements are labeled with the same reference numerals. Detailed Implementation
[0042] refer to Figure 1 The first aspect of this disclosure relates to a propulsion system powered by a DC voltage source 1. The DC voltage source 1 is part of an HVDC grid or HVDC bus 19, and in particular, the voltage source 1 may include a battery or fuel cell. The voltage source 1 may also be another type of voltage source capable of supplying high-voltage direct current. The DC voltage source 1 is connected to a plurality of power electronic components 3 (hereinafter referred to as "power electronic devices") placed in parallel, such that each power electronic device 3 receives a given power from the voltage source 1. In addition to the DC voltage source 1, the HVDC bus 19 also includes a power harness (hereinafter referred to as power input harness 2 because the power harness is located upstream of the power electronic devices 3 in the direction of power flow), and this power harness ensures the electrical connection between the DC voltage source 1 and each power electronic device 3.
[0043] Each power electronic device 3 is connected to the star terminal (stator winding) of the motor 5 via a power output harness 4. Preferably, all power electronic devices 3 power one identical motor 5, but they can also power multiple motors 5, each powered by one or more power electronic devices 3.
[0044] The motor converts the electrical power it receives into mechanical torque. This torque can be specifically supplied to the propeller 6, such as the propeller of an aircraft, which is either directly mechanically connected to the motor 5 or connected to the motor 5 via a reducer that decouples the angular velocity of the motor 5 from the angular velocity of the propeller 6.
[0045] In one embodiment, the propulsion system 10 is fully electric, meaning that the motor alone is capable of powering the propeller 6. Alternatively, the propulsion system 10 can be a hybrid propulsion system 10, which additionally includes a heat engine 7 that provides some of the power required to rotate the propeller 6.
[0046] As is typical, the propulsion system includes a motor controller that controls the angular velocity of the motor 5 and the mechanical torque it can generate. The motor controller includes a sensor 8 configured to measure electrical parameters of the propulsion system 10, which the controller uses to adjust the angular velocity of the motor 5 and / or the mechanical torque generated by the motor 5.
[0047] For each power electronic device 3 included in the propulsion system 10, the motor controller preferably includes at least one sensor 8.
[0048] Due to the architecture of the propulsion system 10, when the power electronic devices 3 are connected in parallel to the voltage source 1, oscillating currents may occur on the power input harness 2 between the power electronic devices 3 whenever there is a difference in electrical load at the input of different power electronic devices 3. When the load difference is high, the frequency of these oscillating currents may approach the resonant frequency of the system and may cause premature damage to the components of the power electronic devices 3 or the power harnesses 2 and 4.
[0049] For at least one of the power electronic components 3, the propulsion system 10 includes a compensation system 18 that receives input measurements acquired by a sensor 8 of the motor controller, indicating the oscillating current flowing between the power electronic component 3 and other power electronic components 3 on the input harness 2. Advantageously, the propulsion system 10 includes the compensation system 18 for each power electronic component 3. These measurements are, for example, measurements of current and / or voltage acquired at the input of the power electronic device 3 including the compensation system 18, or measurements of voltage at the terminals of the HVDC bus 19 and / or measurements of current intensity through the HVDC bus 19. Based on these measurements, the compensation system 18 sends a compensation setpoint for the oscillating current to the motor 5. The sensor 8 is necessary for the motor controller independent of the compensation system 18 for the oscillating current, thus eliminating the need for heavy electronic components such as windings or capacitors in the propulsion system 10 to achieve oscillating current compensation.
[0050] exist Figure 1 In the first embodiment shown, sensor 8 is arranged at the input of power electronics 3 and configured to measure the electrical power input to power electronics 3 and originating from DC voltage source 1. Sensor 8 can be a sensor used by the motor controller independently of compensation system 18 to determine the current intensity through HVDC bus 19 (which is typically used by the motor controller, in particular, to perform so-called "system functions," such as limiting or regulating DC power or estimating torque generated by the motor), or a sensor used by the motor controller to acquire the voltage at the terminals of HVDC bus 19 (which is particularly used for regulating the motor). Therefore, a dedicated sensor for compensation system 18 is not required, and the mass or volume of the propulsion system is not increased. This embodiment also has the advantage that the structure of power electronics 3 allows sensor 8 to be positioned at the input of the power electronics without requiring offset between input wiring harness 2 and sensor 8. Such an offset would require additional housing and wiring harness, which would increase the mass and volume of compensation system 18. Furthermore, this embodiment has the advantage of avoiding parasitic oscillations measured by the sensor, which can resemble rotating currents but are caused by other factors - this would be the case when the sensor 8 is positioned downstream of the power electronic device 3.
[0051] However, other embodiments of sensor 8 are conceivable: sensor 8 may be arranged at bus 19 or in motor 5 to measure the angular position and / or angular velocity of motor 5. Sensor 8 may also be a sensor arranged at the output of power electronics 3 to measure the downstream power of power electronics 3 at power output harness 4.
[0052] In one embodiment, the motor 5 is synchronous, particularly a permanent magnet synchronous motor (PMSM), and the power output harness 4 provides a three-phase power supply to the motor 5. That is, the windings wound on the stator of the motor 5 (referred to as stator windings) comprise three separate windings in a so-called star coupling, which can be supplied with alternating current having phases offset from each other by 120°. In this case, the sensor 8 (but not limited to) may include a sensor arranged at the output of the power electronics 3 at the power output harness 4, for example, to measure the power transmitted to each of the three stator windings of the motor 5.
[0053] In one embodiment, the stator of motor 5 includes two stator windings.
[0054] The stator windings of motor 5 can be connected to a corresponding power output harness 4 via a star coupling 24, enabling the transmission of three-phase power from the power output harness 4 to the stator windings of permanent magnet synchronous motor 5. Each power electronic device 3 is then connected to one of the stator windings or the star coupling 24 of motor 5. Optionally, in one embodiment, an identical motor 5 can be multi-star, i.e., it comprises multiple individual stator windings, each star-coupled 24 and connected to an individual power electronic device 3 via a corresponding harness 4, the stator windings strictly comprising more than three windings. In particular, the stator windings may comprise five or six windings.
[0055] In one embodiment, motor 5 is a multi-star, multi-phase motor that is synchronous or asynchronous with the winding rotor.
[0056] In one embodiment, the compensation system 18 for oscillating current includes a bandpass filter 11 and a PID controller 12. The PID controller 12 may optionally be replaced by an RST controller.
[0057] The bandpass filter 11 is configured to reset the average value of a first parameter, which is the current intensity or associated voltage corresponding to the oscillating current between the power electronic devices 3, such as to obtain an intermediate oscillating current signal 22 at the filter output with an average value of zero but a non-zero amplitude, the non-zero amplitude being equal to the oscillation amplitude of the first parameter. The bandpass frequency of the bandpass filter 11 is determined by electrical parameters measured by the sensor 8 of the motor controller. These electrical parameters may be electrical parameters of the power electronic devices 3, such as resistors or differential inductors, or electrical parameters of the power input harness 2, such as resistors or line inductors. These electrical parameters may also relate to the capacitance of the HVDC bus 19.
[0058] The PID controller 12 accepts an input of an intermediate oscillation signal 22 generated by the bandpass filter 11 and is configured to transmit an oscillation DC setpoint 14 with a frequency equal to the frequency of the intermediate oscillation signal 22, wherein the phase shift is configured to dampen the intermediate oscillation signal 22.
[0059] In some embodiments, the propulsion system 10 may have power redundancy. In other words, the propulsion system includes more than one DC voltage source 1 and correspondingly more than one HVDC bus 19, which are electrically independent. Therefore, in the event of a breakdown or operational failure of one HVDC bus 19, it is ensured that power is still supplied to the motor 5. When the propulsion system includes multiple electrically independent HVDC buses 19, oscillating current can only occur between power electronic components 3 connected to the same HVDC bus 19 via the input harness 2 (which allows such a connection)—oscillating current cannot occur between two power electronic components 3 connected to two separate HVDC buses 19.
[0060] exist Figure 2AIn one embodiment shown, including power redundancy, the propulsion system 10 includes a motor 5 powered via four separate star couplings 24. Thus, the motor 5 includes four separate stator windings, each connected upstream to a separate power electronic component 3. Two of the four power electronic components 3 are powered by a first HVDC bus 19, and the other two are powered by a second HVDC bus 19, electrically independent of the first HVDC bus. Each HVDC bus 19 includes a DC voltage source 1 and a power input harness 2 that allows power generated by the DC voltage source 1 to be transmitted toward the two power electronic components 3 connected thereto. In the event of a failure of the first HVDC bus 19, power will not be supplied to two of the four stator windings of the motor 5, but power will be supplied to the other two stator windings via the second HVDC bus 19, and the propulsion system 10 will function; conversely, in the event of a failure of the second HVDC bus 19, power will be supplied to the other two stator windings. Then, the compensation system 18 as defined above enables the oscillating current flowing on the input harness 2 between the power electronic components 3 connected to the first HVDC bus 19 or between the power electronic components 3 connected to the second HVDC bus 19 to be attenuated.
[0061] exist Figure 2B In another embodiment with power redundancy, the propulsion system 10 includes two separate motors 5. Each motor is powered via two separate star couplings 24. The first star coupling 24 is connected upstream via an output harness 4 to the power electronics component 3 itself, which is connected upstream to a first HVDC bus 19. The second star coupling 24 is also connected upstream via an output harness 4 to the power electronics component 3 itself, which is connected upstream to a second HVDC bus 19. Thus, each of the two motors 5 is partially powered by power from the first HVDC bus 19 and partially powered by power from the second HVDC bus 19. In the event of a failure of the first HVDC bus 19, each motor 5 will be powered by one of its two stator windings, for which power is derived from the second HVDC bus 19, and vice versa in the event of a failure of the second HVDC bus 19. Then, the compensation system 18 as defined above enables the oscillating current flowing on the input harness 2 between the power electronic components 3 connected to the first HVDC bus 19 or between the power electronic components 3 connected to the second HVDC bus 19 to be attenuated.
[0062] In the second aspect and with reference Figure 3This disclosure relates to a method for compensating oscillating currents flowing in a propulsion system 10 as defined above, these currents flowing between power electronic devices 3 and caused by load differences at the inputs of different power electronic devices 3 connected in parallel to a DC voltage source 1. The compensation method includes obtaining measurements 101 representing electrical parameters of the power components 3 via a motor controller sensor 8, and attenuating the oscillating currents based on these measurements.
[0063] In one implementation, obtaining the measurement 101 includes obtaining a measurement of the intensity of the oscillating current flowing between the power electronics 3, and attenuating the oscillating current includes obtaining an intermediate oscillation signal 22 102 by resetting the average intensity value of the oscillating current, for example via a bandpass filter 11, and transmitting an oscillation DC setpoint 14 103 via, for example by applying a reverse oscillation with a frequency substantially equal to the frequency of the intermediate oscillation signal 22 by a PID controller 12, wherein the phase shift is configured to dampen the intermediate oscillation signal 22. As previously stated, these steps can be performed on voltage values rather than current intensity values.
[0064] Figure 4 Existing vector control for controlling a three-phase synchronous motor 5' (i.e., a stator winding comprising three windings) is illustrated. Vector control involves transmitting a command for the current setpoint to the motor 5' using a two-axis coordinate system, referred to as the orthogonal axis q and the direct axis d, centered on and fixed relative to the rotor of the machine 5'. The setpoint 13' on the direct axis d affects only the magnetic flux in the motor 5' and not the mechanical torque generated by the motor, while the setpoint 16' on the orthogonal axis q affects only the mechanical torque and not the magnetic flux of the motor 5'. The values of the current setpoints 13' and 16' are obtained by Park transformation of the current setpoint values transmitted to each stator winding. The setpoints are used by a regulator 9' to determine the phase current to be supplied to each stator winding of the motor 5'. The resulting phase current is then passed through a power converter 3', which outputs power with a current intensity and voltage suitable for the motor 5'.
[0065] exist Figure 5 In one implementation of the compensation method shown, the motor controller applies vector control to the motor 5, and the compensation system 18 uses this vector control to transmit the oscillation DC setpoint 14 generated by the compensation system 18, which is applied only to the direct axis i. d Above. This ensures that the oscillating current attenuates between the power electronics 3 without affecting the mechanical torque generated by the motor 5, and there is no current setpoint on the orthogonal axis i. q Upward transmission. The oscillating DC setpoint 14 complements the current setpoint 13 on the direct axis (provided by the motor controller independently of the compensation method) to generate the combined current setpoint 15. Orthogonal axis i qThe current setpoint 16 is not modified by applying a compensation method.
[0066] It should be noted that since the oscillation DC setpoint 14 has a zero average value, it does not affect the magnetic or thermal state of the motor.
[0067] More specifically, the compensation system 18 may then include a bandpass filter 11 and a PID controller 12 as described above. The bandpass filter 11 receives electrical parameters (e.g., current and / or voltage at the input of the power electronics 3 or at the bus 19) measured by the sensor 8 of the motor controller at its input and generates an intermediate oscillation signal 22.
[0068] Figures 6 to 7C Simulation results for the electric propulsion system 10 as defined above are presented.
[0069] Figure 6 This is a Bode plot. The simulation shown is for a propulsion system 10, which includes two power electronic devices 3, both of which are connected to a motor 5 via a star coupling 24. The compensation method includes compensation only on the direct axis i. d Uploaded 103 setpoints. Several lengths of power input harness 2 were tested (2.5 m; 5.0 m; 7.5 m and 10.0 m). Reference Figure 5 The peak gain and associated frequency values for the four configurations shown are listed in Table 1 below.
[0070] [Table 1]
[0071] Figures 7A to 7C Simulation results for a propulsion system 10 are presented, which includes a permanent magnet synchronous machine 5 and four power electronic devices 3, each power electronic device 3 connected to the motor 5 via a separate star coupling 24. The system includes two DC voltage sources 1, each connected to two power electronic devices 3 placed in parallel. The implemented compensation method includes compensation only on the direct shaft i. d Upward transmission setting point 103.
[0072] Figure 7A The temporal trends of the oscillating current and voltage at bus 19 of power harness 2 are shown. The implementation of the oscillating current compensation method begins at 0.5 seconds. It can be seen that the oscillating current before compensation reaches an amplitude of over 200 amperes, decreasing to a few amperes within a few hundredths of a second after this start. The oscillation amplitude of the voltage at bus 19 is also greatly reduced, from about 60 volts to about 20 volts.
[0073] Figure 7B It is shown that the mechanical torque generated by the propulsion system is essentially unaffected by the implementation of the compensation method for the oscillating current.
[0074] Figure 7C Harmonic analysis of the AC current on bus 19 is presented with and without the compensation method. By implementing the compensation method, the maximum current intensity decreases from 106 amps to approximately 4 amps at the system resonant frequency of approximately 2.5 kHz.
[0075] exist Figure 8 In the third aspect shown, this disclosure relates to an aircraft 25 that includes an electric or hybrid propulsion system 10 as previously defined. In particular, the aircraft 25 may be a light aircraft, such as a VTOL or STOL, for transporting goods and / or personnel over short urban or intercity distances.
Claims
1. An electric or hybrid propulsion system for an aircraft, comprising: -DC voltage bus (19), -At least two power electronic components (3) connected in parallel with the DC voltage bus (19), - A motor controller, the motor controller including a sensor (8) configured to measure electrical parameters representing at least one of the power electronic components (3), the measured electrical parameters specifically including the current intensity flowing through the DC voltage bus (19) and / or the voltage across the terminals of the DC voltage bus (19), Each power electronic component (3) is electrically connected to a separate stator winding, and each stator winding is housed in the motor (5). The motor (5) is configured to convert electrical energy transmitted from the DC voltage bus (19) via the power electronics (3) to the motor (5) into mechanical torque to provide thrust to the aircraft. The propulsion system is characterized by comprising an active compensation system (18) for the at least one power electronic component (3), the active compensation system being configured to attenuate oscillating current flowing between the at least one power electronic component (3) and other power electronic components (3) via a DC voltage bus (19) based on measured electrical parameters.
2. The propulsion system according to claim 1, wherein, The mechanical torque generated by the motor (5) is configured to drive the propeller (6) directly or by means of a reduction gear system.
3. The propulsion system according to claim 2, wherein, The heat engine (7) is directly connected to the propeller or connected to the propeller by means of the reduction system, and the heat engine is configured to generate additional mechanical torque for driving the propeller (6) in addition to the mechanical torque generated by the motor (5).
4. The propulsion system according to any one of claims 1 to 3, wherein, The motor (5) is a permanent magnet synchronous type.
5. The propulsion system according to any one of claims 1 to 4, wherein, The compensation system (18) for the at least one power electronic component (3) includes: - A bandpass filter (11) configured to generate an intermediate oscillation signal (22) by resetting the average value of a first parameter, the first parameter being selected from the voltage at the terminals of the bus (19) and the strength of the current flowing through the bus (19), and - A PID controller (12) or an RST controller, the PID controller or RST controller being configured to receive the intermediate oscillation signal (22) and transmit an oscillation DC setpoint (14) with a frequency substantially equal to the frequency of the intermediate oscillation signal (22), the oscillation DC setpoint (14) including a phase shift relative to the intermediate oscillation signal (22), the phase shift being configured to dampen the intermediate oscillation signal (22).
6. The propulsion system according to any one of claims 1 to 5, comprising: - First DC voltage bus (19), -Second DC voltage bus (19), - Four power electronic components (3), two of which are connected in parallel with the first DC voltage bus (19), and two of which are connected in parallel with the second DC voltage bus (19). The motor (5) includes four stator windings, each of which is powered by one of four power electronic components (3). The two DC voltage buses (19) are not electrically connected.
7. The propulsion system according to any one of claims 1 to 5, comprising: -First DC voltage bus (19) -Second DC voltage bus (19), - Four power electronic components (3), two of which are connected in parallel with the first DC voltage bus, and two of which are connected in parallel with the second DC voltage bus (19). - Two motors (5), each motor (5) including two stator windings, the first stator winding of each motor (5) being powered by a power electronic component (3) connected to the first DC voltage bus (19), and the second stator winding of each motor (5) being powered by a power electronic component (3) connected to the second DC voltage bus (19). The two DC voltage buses (19) are not electrically connected.
8. A method for compensating for an oscillating current flowing in a propulsion system according to any one of claims 1 to 7, the oscillating current flowing between the power electronic components (3) via the DC voltage bus (19), the compensation method comprising: - The sensor (8) obtains (101) a measured value of current or voltage, and - The oscillating current is decayed based on the obtained measurements.
9. The method for compensating oscillating current according to claim 8, wherein, The measured electrical parameters include a first parameter, which is selected from the current intensity flowing through the bus (19) and the voltage at the terminals of the bus (19). Obtaining (101) measurements includes measuring the intensity of the oscillating current. Attenuation includes the following consecutive steps: a. Obtain the intermediate oscillation signal (22) by resetting the average value of the first parameter (102). b. Transmit (103) an oscillation DC setpoint (14) by applying a reverse oscillation with a frequency substantially equal to that of the intermediate oscillation signal (22), the oscillation DC setpoint (14) including a phase shift relative to the intermediate oscillation signal (22), the phase shift being configured to dampen the intermediate oscillation signal (22).
10. An aircraft (25) comprising a propulsion system (10) according to any one of claims 1 to 7.