Airborne power supply power factor correction system and method based on multi-rate control

Abstract

The application discloses a multi-rate control-based aviation power source power factor correction system, comprising a multi-rate control loop and a three-phase current type rectifier; three-phase voltage on an AC side of the three-phase current type rectifier, load voltage and load current on a DC side are connected to the multi-rate control loop as input signals and feedback signals of a control process; the multi-rate control loop adopts an interrupt nested multi-rate control strategy to interpolate three-phase voltage output, and then calculates a rectifier switch tube driving signal of a fast rate, so that the switching frequency of the three-phase current type rectifier is improved without changing the sampling frequency, and the demand of the aviation power system for a method of improving the control frequency under a slow sampling frequency and a power factor correction system is solved.

Description

Technical Field

[0001] This invention belongs to the field of aviation power technology, and more specifically, relates to an aviation power factor correction system and method based on multi-rate control. Background Technology

[0002] Aviation power factor correction systems are a key technology in modern more-electric and all-electric aircraft, designed to optimize power factor, reduce harmonic distortion, and improve energy efficiency to meet the high-quality power requirements of aviation power systems. Aviation electrical systems are characterized by high reliability, high power density, wide input voltage range, and high efficiency; however, nonlinear loads can lead to low power factor and harmonic pollution, affecting system stability and energy transfer efficiency. Therefore, aviation electrical systems urgently require a highly efficient and reliable power factor correction system.

[0003] Three-phase rectifiers, as front-end devices in multi-electric aviation power systems, convert three-phase AC power generated by generators into DC power, making them indispensable key electrical equipment in the system. Compared to three-phase boost rectifiers, three-phase buck rectifiers offer significant advantages such as lower starting current, wider output voltage range, and short-circuit current protection. Therefore, based on their high reliability, three-phase buck rectifiers are particularly suitable for multi-electric aviation. However, in aviation power applications, three-phase buck rectifiers need to operate at high switching frequencies to improve power density and reduce harmonic distortion. High switching frequencies result in extremely short sampling intervals, while longer sampling intervals require sufficient sampling and hold time for analog-to-digital conversion. Especially for three-phase buck rectifiers, digital signal filters need to be introduced during the analog-to-digital conversion stage to suppress electromagnetic interference noise caused by rapid switching speeds. In addition, besides the analog-to-digital conversion process, interruptions such as logic module interruptions, overcurrent and overvoltage protection, and main algorithm execution also significantly increase the computational burden of the sampling interval. Therefore, high sampling frequencies are not feasible in practical applications, and the sampling frequency becomes a key factor limiting the rectifier control frequency. How to complete the control algorithm within short interrupt intervals, ensure that interrupts do not overflow, and increase the control frequency or switching frequency at low sampling frequencies are urgent technical problems to be solved in the field of aviation power supplies.

[0004] Multi-rate technology effectively increases the system's control and switching frequencies by calculating multiple control inputs within a single sampling interrupt while ensuring sufficient sampling intervals. This significantly improves the control or switching frequency of a three-phase buck rectifier at low sampling frequencies. This strategy is particularly suitable for aerospace power supplies where chip computing power is limited.

[0005] Power factor correction (PFCD) systems are a key technology in modern more-electric and all-electric aircraft, aiming to optimize power factor, reduce harmonic distortion, and improve energy efficiency. Three-phase buck rectifiers, as core equipment in aviation power systems, require high switching frequencies to improve performance. However, high switching frequencies result in short sampling intervals and heavy computational burdens, limiting the increase in control frequency. Multi-rate technology, by calculating multiple control inputs within a single sampling interrupt, effectively improves the system's control and switching frequencies at low sampling frequencies, providing an efficient and reliable solution for aviation power applications. Therefore, the aviation power field urgently needs an aviation power factor correction system based on multi-rate control. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an aviation power supply power factor correction system and method based on multi-rate control, so as to solve the aviation power supply's requirements for power factor correction system and high switching frequency.

[0007] To achieve the above-mentioned objectives, the present invention provides an aviation power factor correction system based on multi-rate control, characterized in that it includes: a multi-rate control loop and a three-phase current-type rectifier;

[0008] The multi-rate control loop includes: a phase-locked loop, a fast-rate phase voltage calculation module, a voltage loop, a reference output current generation module, a current loop, a modulation signal generation module, and a space vector modulation module.

[0009] The multi-rate control loop acquires the three-phase voltage v of the three-phase current-source rectifier. xs x = a, b, c represent the three phases and serve as the inputs to the high-rate phase voltage calculation module and the phase-locked loop. Then, Lagrange interpolation is used to calculate the three-phase voltage v. xs Interpolation is performed to obtain the fast-rate three-phase voltage v. xf The voltage loop in the multi-rate control circuit collects the output voltage v0 of the three-phase current-source rectifier and calculates the desired output power. Output voltage v0, high-speed three-phase voltage v xf and expected output power Simultaneously, it serves as the input to the reference output current generation module, thereby calculating the reference output current. The current loop in the multi-rate control circuit will connect the output current i0 of the three-phase current-source rectifier with the reference output current. Calculate the desired output current i 0PIf The modulation signal generation module receives the desired output current i. 0PIf and fast-rate three-phase voltage v xf The modulation signal m was then calculated. x Then, the space vector modulation module modulates the signal m.x Space vector modulation is performed to calculate the three-phase voltage v with high speed. xf A drive signal of the same rate is used to control the turn-off of the switching transistors in the three-phase current-source rectifier.

[0010] The objective of this invention is achieved as follows:

[0011] This invention relates to an aviation power factor correction system based on multi-rate control, comprising: a multi-rate control loop and a three-phase current-source rectifier; the three-phase voltage on the AC side of the three-phase current-source rectifier, the load voltage on the DC side, and the load current are connected to the multi-rate control loop as input and feedback signals for the control process; the multi-rate control loop uses an interrupt-nested multi-rate control strategy to interpolate the three-phase voltage output, and then calculates the fast-rate rectifier switching transistor drive signal, thereby increasing the switching frequency of the three-phase current-source rectifier without changing the sampling frequency, and also solving the aviation power system's need for a method to increase the control frequency under slow sampling frequency and a power factor correction system.

[0012] Meanwhile, the aviation power factor correction system and method based on multi-rate control of the present invention also have the following beneficial effects:

[0013] (1) By using multi-rate control of aviation power factor correction, the system can stabilize the grid voltage, avoid voltage fluctuations from affecting the normal operation of the equipment, and improve the stability of the equipment.

[0014] (2) The multi-rate control aviation power factor correction system improves the actual output power of the equipment by optimizing the power factor, while reducing the heat generated by reactive current, thereby reducing the energy loss and temperature rise of the equipment and extending the service life of the equipment.

[0015] (3) Using a multi-rate controlled aviation power factor correction system can also free up the capacity of transformers and lines, and use the energy reduced in reactive power to support more loads or cope with emergencies, thereby increasing the capacity limit of the equipment.

[0016] (4) This invention improves the switching frequency of the three-phase current-type rectifier through a multi-rate control loop, so that the control algorithm can adjust the duty cycle more flexibly to suit a variety of application scenarios;

[0017] (5) The present invention does not require increasing the sampling rate, reduces the requirement for the sampling rate, avoids the risk of high-frequency sampling exacerbating voltage ripple, and reduces the size and cost of the sampling element. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the aviation power factor correction system based on multi-rate control according to the present invention.

[0019] Figure 2 This is a flowchart of the aviation power factor correction method based on multi-rate control according to the present invention;

[0020] Figure 3 This is a schematic diagram of the interrupt nested multi-rate control strategy. Detailed Implementation

[0021] The specific embodiments of the present invention will now be described with reference to the accompanying drawings to enable those skilled in the art to better understand the invention. It should be particularly noted that in the following description, detailed descriptions of known functions and designs that might obscure the main content of the invention will be omitted here.

[0022] Example

[0023] In this embodiment, as Figure 1 As shown, the present invention provides an aviation power factor correction system based on multi-rate control, comprising: a multi-rate control loop 1 and a three-phase current-type rectifier 2;

[0024] The multi-rate control loop 1 includes a phase-locked loop 3, a fast-rate phase voltage calculation module 4, a voltage loop 5, a reference output current generation module 8, a current loop 9, a modulation signal generator 12, and a space vector modulation module 13;

[0025] Among them, voltage loop 5 is composed of voltage difference calculation unit 6 and proportional-integral controller 7, and current loop 9 is composed of current difference calculation unit 10 and proportional-integral controller 11.

[0026] Multi-rate control loop 1 acquires the three-phase voltage v of three-phase current-source rectifier 2. xs x = a, b, c represent the three phases and serve as inputs to the fast-rate phase voltage calculation module 4 and the phase-locked loop 3. Then, Lagrange interpolation is used to calculate the three-phase voltage v. xs Interpolation is performed to obtain the fast-rate three-phase voltage v. xf The voltage loop 5 in the multi-rate control circuit collects the output voltage v0 of the three-phase current-source rectifier and calculates the desired output power. Output voltage v0, high-speed three-phase voltage v xf and expected output power Simultaneously used as a reference output current generation

[0027] The module 8 input is used to calculate the reference output current. The current loop 9 in the multi-rate control circuit is based on the output current i0 of the three-phase current-source rectifier 2 and the reference output current. Calculate the desired output current i 0PIf The modulation signal generation module 12 receives the desired output current i. 0PIfand fast-rate three-phase voltage v xf The modulation signal m was then calculated. x Then, the space vector modulation module 13 modulates the signal m. x Space vector modulation is performed to calculate the three-phase voltage v with high speed. xf A drive signal of the same rate is used to control the turn-off of the switching transistors in the three-phase current-source rectifier.

[0028] This invention also provides a power factor correction method for aviation power supplies based on multi-rate control, such as... Figure 2 As shown, it includes the following steps:

[0029] (1) Define the three-phase voltage v xs A complete sampling period is T s , will T s Each time interval after being divided into N equal parts is defined as the fast rate period T. f T f =T s / N; Let the three-phase voltage of the kth sampling period be v. xs (k) and the corresponding phase angle is θ xs (k), output voltage is v0(k), output current is i0(k); the fast-rate three-phase voltage in the i-th fast-rate cycle of the k-th sampling period is v xf (i|k) and the corresponding phase angle is θ xf (i|k), output voltage is v0(i|k), output current is i0(i|k);

[0030] (2) Calculate the three-phase voltage V using a phase-locked loop. xs The phase angle θ of (k) xs (k), then the three-phase voltage v xs (k) and its phase angle θ xs (k) Input to the fast-rate phase voltage calculation module;

[0031] (3) The fast rate calculation module calculates the fast rate three-phase voltage as v using the Lagrange interpolation method. xf (i|k):

[0032] v xf (i|k)=v xs (k-1)l k-1 +v xs (k)l k +v xs (k+1)l k+1

[0033] Among them, l k-1 l k l k+1Let be the Lagrange interpolation basis functions for the (k-1), k, and k+1 sampling periods, respectively, and their expressions are as follows:

[0034]

[0035] (4) The voltage difference calculation unit compares the output voltage v0(k) with the desired output voltage. The difference is calculated, and then the difference is passed through a proportional-integral controller to obtain the desired output power.

[0036] (5) The reference output current generation module receives the output voltage v0(k) and the expected output power. and fast-rate three-phase voltage v xf (i|k), and then calculate the reference output current.

[0037]

[0038] Among them, G * (i|k) represents the desired conductance of each phase on the AC side of the three-phase current-source rectifier, and its expression is:

[0039]

[0040] (6) The current difference calculation unit compares the acquired output current i0(i|k) with the reference output current. The difference is calculated, and then the difference is used by a proportional-integral controller to calculate the desired output current i. oPIf (i|k);

[0041] (7) The modulation signal generation module receives the high-speed three-phase voltage v xf (i|k) and desired output current i oPIf (i|k), and then multiply the two to calculate the modulation signal mx;

[0042] m a =v af (i|k)i oPIf (i|k)

[0043] m b =v bf (i|k)i oPIf (i|k)

[0044] m c =v cf (i|k)i oPIf (i|k)

[0045] (8) Modulate the signal m through the space vector modulation module. xSpace vector modulation is performed to calculate the three-phase voltage v with high speed. xf (i|k) A drive signal of the same rate is used to control the turn-off of the switching transistors in the three-phase current-source rectifier.

[0046] (9) Let i = i + 1, then return to step (3) until i = N, then let the sampling period k increase by 1, and return to step (2) to enter the modulation of the next sampling period.

[0047] In this embodiment, the fast-rate three-phase voltage, modulation signal, and drive signal sequence are as follows: Figure 3 As shown, the high-speed three-phase voltage is v xf (i|k) is generated by the fast-rate phase voltage calculation module and compared with the sampled three-phase voltage v. xs (k) has increased the number of data points by N times. Since the modulation signal corresponds to the fast-rate phase voltage, the final switching transistor drive signal frequency reaches the fast-rate target.

[0048] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A power factor correction system for aviation power supplies based on multi-rate control, characterized in that, include: Multi-rate control circuit and three-phase current-source rectifier; The multi-rate control loop includes: a phase-locked loop, a fast-rate phase voltage calculation module, a voltage loop, a reference output current generation module, a current loop, a modulation signal generation module, and a space vector modulation module. The multi-rate control loop acquires the three-phase voltage of the three-phase current-source rectifier. , Representing the three phases, and serving as the input to the fast-rate phase voltage calculation module and the phase-locked loop, the three-phase voltage is then calculated using Lagrange interpolation. Interpolation is performed to obtain the fast-rate three-phase voltage. The voltage loop in the multi-rate control circuit collects the output voltage of the three-phase current-source rectifier. And calculate the desired output power. Output voltage High-speed three-phase voltage and expected output power Simultaneously, it serves as the input to the reference output current generation module, thereby calculating the reference output current. The current loop in the multi-rate control circuit controls the output current of the three-phase current-source rectifier. and reference output current Calculate the desired output current The modulation signal generation module receives the desired output current. and high-speed three-phase voltage The modulation signal was then calculated. Then, the modulated signal is modulated by the space vector modulation module. Space vector modulation is performed to calculate the three-phase voltage with high speed. A drive signal of the same rate is used to control the turn-off of the switching transistors in the three-phase current-source rectifier.

2. The aviation power factor correction system based on multi-rate control according to claim 1, characterized in that, The voltage loop consists of a voltage difference calculation unit and a proportional-integral controller.

3. The aviation power factor correction system based on multi-rate control according to claim 1, characterized in that, The current loop consists of a current difference calculation unit and a proportional-integral controller.

4. A power factor correction method for aircraft power supplies based on multi-rate control, characterized in that, Includes the following steps: (1) Define three-phase voltage A complete sampling period is ,Will Divided into equal parts Each time interval after a period is defined as a fast rate cycle. , , Represents three phases; Record the first The three-phase voltage for each sampling period is and the corresponding phase angle is Output voltage is Output current is ;No. The first sampling period The fast-rate three-phase voltage for one fast-rate cycle is and the corresponding phase angle is Output voltage is The output current is ; (2) Calculate the three-phase voltage using a phase-locked loop. phase angle Then the three-phase voltage and its phase angle Input to the high-rate phase voltage calculation module; (3) The fast rate calculation module calculates the fast rate three-phase voltage using the Lagrange interpolation method. : ； in, , , The first , and The expressions for the Lagrange interpolation basis functions for each sampling period are as follows: ； ； ； (4) The voltage difference calculation unit will output the voltage With the desired output voltage The difference is calculated, and then the difference is passed through a proportional-integral controller to obtain the desired output power. ; (5) The reference output current generation module receives the output voltage. Expected output power and high-speed three-phase voltage Then calculate the reference output current. : ； in, Let be the desired conductance of each phase on the AC side of a three-phase current-source rectifier, expressed as: ； (6) The current difference calculation unit will collect the output current. With reference output current The difference is calculated, and then the difference is used by a proportional-integral controller to calculate the desired output current. ; (7) The modulation signal generation module receives the high-speed three-phase voltage. and expected output current Then multiply the two to calculate the modulation signal. ; ； (8) Modulate the signal using the space vector modulation module. Space vector modulation is performed to calculate the three-phase voltage with high speed. A drive signal of the same rate is used to control the turn-off of the switching transistors in the three-phase current-source rectifier. (9) Order Then return to step (3) until Then, set the sampling period. Add 1, return to step (2) to enter the modulation of the next sampling period.

Images