Active power decoupling circuit, active power decoupling method and device

Abstract

The present invention provides an active power decoupling circuit, an active power decoupling method and a device. The circuit includes: a decoupling controller, a first switching transistor, a second switching transistor, a decoupling inductor, a first capacitor and a second capacitor; the first switching transistor and the second switching transistor are connected in series, the first capacitor and the second capacitor are connected in series, one end of the first switching transistor and one end of the first capacitor are connected to the upper output end of the rectifier and the upper input end of the inverter, one end of the second switching transistor and one end of the second capacitor are connected to the lower output end of the rectifier and the lower input end of the inverter; the decoupling inductor is connected to the midpoint between the first switching transistor and the second switching transistor and the midpoint between the first capacitor and the second capacitor; the decoupling controller is connected to the control ends of the first switching transistor and the second switching transistor, and is used to control the on / off of the first switching transistor and the second switching transistor according to the DC bus voltage and the second voltage across the second capacitor. The present invention can achieve active power decoupling without a current sensor, improve reliability and reduce costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of power decoupling, and particularly relates to an active power decoupling circuit, an active power decoupling method and a device. Background Art

[0002] AC-DC-AC converters are widely used in fields such as photovoltaic, wind power, and rail transit. With the continuous development of technology, the requirements for the reliability and power density of power electronic systems are gradually increasing. Energy storage devices are crucial for reducing the volume of power electronic systems and improving system reliability. In recent years, scholars have conducted many studies on reducing the DC bus capacitance. For an input three-phase balanced AC-DC-AC converter, the power factor needs to be achieved on the grid side, and double-frequency pulsating power will be generated in all three phases. Due to the phase relationship, the pulsating powers cancel each other out and thus do not input into the DC bus. However, the secondary pulsating power of a single-phase AC-DC-AC converter cannot be cancelled out, and the inherent secondary pulsating power inputs into the DC bus, resulting in secondary pulsation of the bus voltage and causing phenomena such as beat frequency in traction motors and an increase in the odd harmonic content of grid-side currents. In order to suppress the secondary ripple of the bus voltage, energy storage devices are needed to store the secondary ripple energy to achieve power decoupling. There are mainly two ways of power decoupling: passive and active. Passive power decoupling uses the resonance of inductors and capacitors to absorb the secondary ripple, but the resonance voltage is uncontrollable, the adjustment range is limited by the DC bus, and large-capacity device energy storage elements are required; in addition, the filtering frequency of the resonance circuit is single and the frequency adaptability is poor. The active power decoupling method introduces power electronic devices, cooperates with small-capacity energy storage elements, and actively suppresses harmonic power to make up for the deficiencies of passive power decoupling.

[0003] The control of the active power decoupling circuit usually focuses on the voltage of the energy storage capacitor. All the bus ripple power is absorbed by the decoupling power, and the corresponding reference decoupling voltage can be calculated according to the pulsating power. Existing active power decoupling methods all need to add a current sensor in the decoupling loop to collect the decoupling inductor current, but traditional current sensors have a small range, poor insulation performance, and poor anti-electromagnetic interference ability, while Hall and fiber optic current sensors with better performance have higher costs. Summary of the Invention

[0004] The present invention provides an active power decoupling circuit, an active power decoupling method and a device to solve the problems of poor anti-interference ability and high cost in realizing decoupling by adding a current sensor to collect the decoupling inductor current in the prior art.

[0005] For the above purposes, an embodiment of the present invention provides an active power decoupling circuit, including: a decoupling controller, a first switching transistor, a second switching transistor, a decoupling inductor, a first capacitor, and a second capacitor; the first switching transistor and the second switching transistor are connected in series, the first capacitor and the second capacitor are connected in series, one end of the first switching transistor and one end of the first capacitor are connected to the upper output end of the rectifier, and one end of the second switching transistor and one end of the second capacitor are connected to the lower output end of the rectifier; the first end of the decoupling inductor is connected between the first switching transistor and the second switching transistor, and the other end of the decoupling inductor is connected between the first capacitor and the second capacitor; one end of the first capacitor is further connected to the upper input end of the inverter, and one end of the second capacitor is further connected to the lower input end of the inverter to output a DC bus voltage to the inverter; the output end of the decoupling controller is connected to the control ends of the first switching transistor and the second switching transistor, and the decoupling controller is configured to obtain the DC bus voltage output by the active power decoupling circuit and the second voltage across the second capacitor, and control the on / off of the first switching transistor and the second switching transistor according to the DC bus voltage and the second voltage.

[0006] Based on the same inventive concept, an embodiment of the present invention further provides an active power decoupling method applied to the foregoing active power decoupling circuit. The method includes: extracting an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and performing transformation control on the orthogonal signal to obtain a reference value of the inductor current of the decoupling inductor; obtaining an estimated value of the inductor current of the decoupling inductor by using an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty cycle in the active power decoupling circuit, and cyclically updating the duty cycle according to the current difference between the reference value of the inductor current and the estimated value of the inductor current until there is no secondary ripple in the DC bus voltage. The duty cycle is the ratio of the on-time of the first switching transistor to the control period; controlling the on / off of the first switching transistor and the second switching transistor according to the final duty cycle.

[0007] Optionally, the extracting an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit includes: subtracting the DC bus voltage from the DC bus reference voltage to obtain a voltage difference therebetween; processing the voltage difference by using a second-order generalized integrator to extract the orthogonal signal.

[0008] Optionally, the performing transformation control on the orthogonal signal to obtain a reference value of the inductor current of the decoupling inductor includes: performing a rotation transformation on the orthogonal signal to obtain a ripple reference value of the second voltage; processing the ripple reference value by using a proportional-resonant controller to obtain a reference value of the inductor current of the decoupling inductor.

[0009] Optionally, the method for obtaining the estimated value of the inductance current of the decoupling inductor by processing using an observer based on the DC bus voltage, the second voltage across the second capacitor, and the duty cycle includes: obtaining a first relationship between the DC bus voltage, the second voltage across the second capacitor, the duty cycle, and the inductance current value of the decoupling inductor based on the active power decoupling circuit; and obtaining the estimated value of the inductance current of the decoupling inductor by applying a Romberg observer according to the first relationship.

[0010] Optionally, the method for obtaining the estimated value of the inductance current of the decoupling inductor by applying a Romberg observer according to the first relationship includes: obtaining an observer mathematical model according to the first relationship in combination with the Romberg observer, satisfying the following relationship:

[0011]

[0012] where L is the inductance value of the decoupling inductor, is the estimated value of the inductance current flowing through the decoupling inductor, u c2 is the measured value of the second voltage across the second capacitor, is the estimated value of the second voltage across the second capacitor, u dc is the DC bus voltage, C is the capacitance value of the second capacitor, k1 is the first gain of the Romberg observer, and k2 is the second gain of the Romberg observer; and obtaining the estimated value of the inductance current of the decoupling inductor based on the observer mathematical model.

[0013] Optionally, the method for controlling the on / off of the first switch tube and the second switch tube according to the final duty cycle includes: processing using a pulse width modulator according to the duty cycle to obtain a first control signal and a second control signal; and controlling the on / off of the first switch tube according to the first control signal and controlling the on / off of the second switch tube according to the second control signal.

[0014] Based on the same inventive concept, an embodiment of the present invention further provides an active power decoupling device, including: a reference current acquisition module, configured to extract orthogonal signals by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and perform transformation control on the orthogonal signals to obtain a reference value of the inductor current of the decoupling inductor; a duty ratio acquisition module, configured to obtain an estimated value of the inductor current of the decoupling inductor by using an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty ratio in the active power decoupling circuit, and cyclically update the duty ratio according to the current difference between the reference value of the inductor current and the estimated value of the inductor current until there is no secondary ripple in the DC bus voltage, where the duty ratio is the ratio of the on-time of the first switch tube to the control period; a decoupling control module, configured to control the on / off of the first switch tube and the second switch tube according to the final duty ratio.

[0015] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where when the processor executes the program, the foregoing method is implemented.

[0016] Based on the same inventive concept, an embodiment of the present invention further provides a computer storage medium, in which at least one executable instruction is stored, and the executable instruction causes the processor to execute the foregoing method.

[0017] The beneficial effects of the present invention are as follows: As can be seen from the above, an active power decoupling circuit, an active power decoupling method and device provided by an embodiment of the present invention, the circuit includes: a decoupling controller, a first switch tube, a second switch tube, a decoupling inductor, a first capacitor, and a second capacitor; the first switch tube and the second switch tube are connected in series, the first capacitor and the second capacitor are connected in series, one end of the first switch tube and one end of the first capacitor are connected to the upper output end of the rectifier, and one end of the second switch tube and one end of the second capacitor are connected to the lower output end of the rectifier; the first end of the decoupling inductor is connected between the first switch tube and the second switch tube, and the other end of the decoupling inductor is connected between the first capacitor and the second capacitor; one end of the first capacitor is further connected to the upper input end of the inverter, and one end of the second capacitor is further connected to the lower input end of the inverter to output a DC bus voltage to the inverter; the output end of the decoupling controller is connected to the control ends of the first switch tube and the second switch tube, and the decoupling controller is configured to obtain the DC bus voltage output by the active power decoupling circuit and the second voltage across the second capacitor, and control the on / off of the first switch tube and the second switch tube according to the DC bus voltage and the second voltage, which can achieve active power decoupling without a current sensor, improve reliability, and reduce costs. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of the active power decoupling circuit in the embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of the working principle of the active power decoupling circuit in the embodiment of the present invention;

[0021] Figure 3 It is a schematic flow chart of the active power decoupling method in the embodiment of the present invention;

[0022] Figure 4 It is a schematic diagram of the control block diagram of the decoupling controller in the embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of the control block diagram of the Romberg observer in the embodiment of the present invention;

[0024] Figure 6 It is a schematic structural diagram of the active power decoupling device in the embodiment of the present invention;

[0025] Figure 7 It is a schematic diagram of the electronic device in the embodiment of the present invention. Specific embodiments

[0026] To make the objectives, technical solutions, and advantages of the present disclosure clearer and more understandable, the following further elaborates on the present disclosure in detail in conjunction with specific embodiments and with reference to the accompanying drawings.

[0027] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second" and similar terms used in the embodiments of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0028] An active power decoupling circuit provided by an embodiment of the present invention is as Figure 1 shown. The active power decoupling circuit includes: a decoupling controller, a first switching transistor SD1, a second switching transistor SD2, a decoupling inductor L, a first capacitor C1, and a second capacitor C2. The first switching transistor SD1 and the second switching transistor SD2 are connected in series. The first capacitor C1 and the second capacitor C2 are connected in series. One end of the first switching transistor SD1 and one end of the first capacitor C1 are connected to the upper output terminal of the rectifier. One end of the second switching transistor SD2 and one end of the second capacitor C2 are connected to the lower output terminal of the rectifier. The decoupling inductor L is connected to the midpoint between the first switching transistor SD1 and the second switching transistor SD2 and the midpoint between the first capacitor C1 and the second capacitor C2. Specifically, the first end of the decoupling inductor L is connected between the first switching transistor SD1 and the second switching transistor SD2, and the other end of the decoupling inductor L is connected between the first capacitor C1 and the second capacitor C2. One end of the first capacitor C1 is further connected to the upper input terminal of the inverter, and one end of the second capacitor C2 is further connected to the lower input terminal of the inverter to output a DC bus voltage u dc to the inverter. The output terminal of the decoupling controller is connected to the control terminals of the first switching transistor SD1 and the second switching transistor SD2. The decoupling controller is configured to obtain the DC bus voltage u dc output by the active power decoupling circuit and the second voltage u c2 across the second capacitor C2, and control the on / off of the first switching transistor SD1 and the second switching transistor SD2 according to the DC bus voltage u dc and the second voltage u c2 to achieve active power decoupling.

[0029] Continue to refer to Figure 1 , the AC power supply U sOne end of it is connected to the midpoint of the first bridge arm of the rectifier through the AC inductor Ls, and the AC power supply U s The other end is connected to the midpoint of the second bridge arm of the rectifier. The first bridge arm of the rectifier includes the third switch tube Sa1 and the fourth switch tube Sa2 connected in series with each other, and the first bridge arm of the rectifier includes the fifth switch tube Sb1 and the sixth switch tube Sb2 connected in series with each other. The inverter includes three bridge arms A, B, and C. The A bridge arm includes the seventh switch tube SA1 and the eighth switch tube SA2 connected in series with each other, the B bridge arm includes the ninth switch tube SB1 and the tenth switch tube SB2 connected in series with each other, and the C bridge arm includes the eleventh switch tube SC1 and the twelfth switch tube SC2 connected in series with each other. The midpoints of the three bridge arms A, B, and C are respectively connected to the load.

[0030] In the embodiment of the present invention, the rectifier at the front end of the active power decoupling circuit can be equivalent to a voltage source, and the inverter and the load at the rear end are equivalent to a resistor. There are four operating modes according to the active power decoupling topology and the direction of the decoupling inductor current. As Figure 2 shown, the working principle of the active power decoupling circuit is as follows:

[0031] In the first operating mode, the inductor current i of the decoupling inductor L L flows into the midpoint of the first capacitor C1 and the second capacitor C2. The first switch tube SD1 is turned off, and the second switch tube SD2 is turned on. As Figure 2 shown in a, the decoupling inductor L forms a loop with the second switch tube SD2 and the second capacitor C2, and the power is exchanged between the decoupling inductor L and the second capacitor C2, that is, the decoupling inductor L discharges and the capacitor C2 is charged. The DC voltage source u dc forms a loop with the first capacitor C1 and the second switch tube SD2. The first capacitor C1 exchanges power with the DC power supply, that is, the first capacitor C1 discharges, and the energy flows to the DC bus. Therefore, in this operating mode, the output current of the active power decoupling circuit is compensated to the DC bus.

[0032] In the first operating mode, the inductor current i of the decoupling inductor L L flows into the midpoint of the first capacitor C1 and the second capacitor C2. The first switch tube SD1 is turned on, and the second switch tube SD2 is turned off. As Figure 2 shown in b, the decoupling inductor L forms a loop with the first switch tube SD1 and the first capacitor C1, and the power is exchanged between the decoupling inductor L and the first capacitor C1, that is, the decoupling inductor L is charged and the first capacitor C1 discharges. The DC voltage source u dc forms a loop with the second capacitor C2 and the first switch tube SD1. The second capacitor C2 exchanges power with the DC power supply, that is, the second capacitor C2 is charged, and the energy flows out of the DC bus. Therefore, in this second operating mode, the active power decoupling circuit absorbs the second harmonic pulsating current from the DC bus.

[0033] In the third operating mode, the inductor current i of the decoupling inductor LL At the midpoint of the output capacitor, the first switching transistor SD1 is turned off and the second switching transistor SD2 is turned on. As shown in Figure 2 c, the decoupling inductor L forms a loop with the second switching transistor SD2 and the second capacitor C2. Power is exchanged between the decoupling inductor L and the second capacitor C2, that is, the decoupling inductor L is charged and the second capacitor C2 is discharged. The DC voltage source u dc forms a loop with the first capacitor C1 and the second switching transistor SD2. Power is exchanged between the first capacitor C1 and the DC power supply, that is, the first capacitor C1 is charged and energy flows out of the DC bus. Therefore, in this third operating mode, the active power decoupling circuit absorbs the second-order pulsating current from the DC bus.

[0034] In the fourth operating mode, the inductor current i of the decoupling inductor L L flows out of the midpoint of the output capacitor. The first switching transistor SD1 is turned on and the second switching transistor SD2 is turned off. As shown in Figure 2 d, the decoupling inductor L forms a loop with the first switching transistor SD1 and the first capacitor C1. Power is exchanged between the decoupling inductor L and the first capacitor C1, that is, the decoupling inductor L is discharged and the first capacitor C1 is charged. The DC voltage source u dc forms a loop with the second capacitor C2 and the first switching transistor SD1. Power is exchanged between the second capacitor C2 and the DC power supply, that is, the second capacitor C2 is discharged and energy flows to the DC bus. Therefore, in this fourth operating mode, the active power decoupling circuit outputs current to compensate the DC bus.

[0035] An embodiment of the present invention provides an active power decoupling method. The active power decoupling method of the embodiment of the present invention is applied to the Figure 1 active power decoupling circuit in, and is specifically applied to the Figure 1 decoupling controller in. As shown in the appendix Figure 3 , the active power decoupling method includes:

[0036] Step S11: Extract orthogonal signals by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and perform transformation control on the orthogonal signals to obtain the reference value of the inductor current of the decoupling inductor.

[0037] In the embodiment of the present invention, when the single-phase rectifier operates normally, the time-domain expressions of the grid-side input voltage and the grid-side input current are as follows:

[0038]

[0039]

[0040]

[0041] where u s is the grid-side input voltage, i s is the grid-side input current, uL is the voltage across the AC inductor Ls, U rms and I rms are the effective values of the grid-side input voltage and the grid-side input current respectively, ω0 is the grid voltage angular frequency, is the input power factor angle.

[0042] Since the rectifier usually controls the unity power factor on the grid side and the power factor angle is 0, considering the grid-side AC inductor Ls to calculate the output power of the rectifier side, according to the calculation results, it is divided into a DC component P dc and a second-harmonic component p ripple .

[0043] P dc = U rms I rms (4)

[0044]

[0045] According to the capacitor splitting decoupling topology, the DC power is consumed by the subsequent load, and the second-harmonic pulsating power needs to be absorbed by the decoupling circuit. Considering that the capacitance values C1 = C2 = C, to achieve power decoupling, the sum of the DC components of the voltages of the first capacitor C1 and the second capacitor C2 should be equal to the DC bus voltage reference value, and the power generated by the AC components of the voltages of the first capacitor C1 and the second capacitor C2 exactly compensates for the second pulsating power of the DC bus, and the sum of the AC components is 0, then there is:

[0046]

[0047]

[0048] Among them, U dc is the bus voltage setting value, u c is the AC component of the capacitor voltage, U crms is the effective value of u c , ω1 is the angular frequency of u c , θ is the initial phase of u c , according to KCL and the voltage-current relationship of the capacitor, the inductor current i L of the decoupling inductor is:

[0049]

[0050] The total power p APD provided by the active power decoupling circuit includes the power of the inductor and the capacitor:

[0051]

[0052] According to the requirements of active power decoupling, the total power provided by the decoupling circuit cancels out the ripple power of the input DC link, that is, pAPD The frequency is the same as that of the second - harmonic component p ripple The angular frequencies are the same, the phases are opposite, and the amplitudes are the same. Solving gives:

[0053] ω1=ω0 (10)

[0054]

[0055]

[0056] Therefore, it is only necessary to control the first voltage u across the first capacitor c1 and the second voltage u across the second capacitor c2 to change according to formula (6), and the active power decoupling circuit can eliminate the second - order ripple of the bus voltage. For the convenience of the subsequent design of the decoupling controller, first establish a mathematical model according to the working principle. When the first switch tube SD1 is turned on and the second switch tube SD2 is turned off, the mathematical model of the decoupling controller is:

[0057]

[0058] When the first switch tube SD1 is turned off and the second switch tube SD2 is turned on, the mathematical model of the decoupling controller is

[0059]

[0060] Taking the average over one cycle, assuming that the ratio of the on - time of the first switch tube SD1 to the entire control cycle is the duty cycle d, the average model of the system over one cycle is:

[0061]

[0062] According to formula (6) and formula (15), based on the active power decoupling circuit, obtain the relationships between the DC bus voltage, the second voltage across the second capacitor, the duty cycle, and the inductor current value of the decoupling inductor:

[0063]

[0064] where L is the inductance value of the decoupling inductor, i L is the inductor current value flowing through the decoupling inductor, u c2 is the measured value of the second voltage across the second capacitor, u dc is the DC bus voltage, and C is the capacitance value of the first capacitor and the second capacitor.

[0065] The control block diagram of the decoupling controller in the embodiment of the present invention is as shown in Figure 4As shown. In step S11, the DC bus voltage is subtracted from the DC bus reference voltage to obtain the voltage difference between the two; a second-order generalized integrator (SOGI) is used to process the voltage difference to extract the quadrature signal. When the given input is a sine signal, the transfer function of the second-order generalized integrator (SOGI) is as shown in the following equation (17).

[0066]

[0067] Where, U α (s) is the input signal estimated by the second-order generalized integrator, U β (s) is the quadrature signal of the voltage difference, k is the damping coefficient, U(s) is the voltage difference, and ω is twice the frequency ω0 of the DC bus voltage. The value of the damping coefficient k determines the performance of the second-order generalized integrator (SOGI).

[0068] The output of the SOGI is an orthogonal double-frequency AC signal. The quadrature signal is subjected to a rotation transformation to obtain the ripple reference value U c2ref of the second voltage; the proportional-resonant controller is applied to the ripple reference value to obtain the reference value i Lref of the inductance current of the decoupling inductor. Continuing to refer to Figure 4 , the ripple reference value U c2 of the second voltage u c2ref of the second capacitor C2 can be obtained through the rotation transformation 2s / 2r. The voltage d-axis component U d extracted from the rotation transformation 2s / 2r is the ripple reference value U c2 of the second voltage u c2ref , and the mathematical model is as follows:

[0069]

[0070] Where, ω0t is the angle between the αβ coordinate system and the dq coordinate system. The ripple reference value U c2 of the second voltage u c2ref passes through the proportional-resonant (PR) controller to obtain the reference value i Lref of the inductance current of the decoupling inductor. The transfer function of the PR controller is as follows:

[0071]

[0072] Where, K p is the proportional coefficient of the PR controller, K R is the resonant coefficient, ω c is the bandwidth, and ω0 is the cut-off frequency, that is, the frequency of the DC bus voltage.

[0073] Step S12: Based on the DC bus voltage, the second voltage across the second capacitor, and the duty cycle in the active power decoupling circuit, an observer is used to obtain an estimated value of the inductor current of the decoupling inductor. Then, based on the current difference between the reference inductor current value and the estimated inductor current value, the duty cycle is cyclically updated until there is no secondary ripple in the DC bus voltage. The duty cycle is the ratio of the on-time of the first switch tube to the control period.

[0074] In step S12, based on the active power decoupling circuit, a first relationship between the DC bus voltage, the second voltage across the second capacitor, the duty cycle, and the inductor current value of the decoupling inductor is obtained. According to the first relationship, a Romberg observer is used to obtain an estimated value of the inductor current of the decoupling inductor. This first relationship is the previously obtained equation (16).

[0075] In the embodiment of the present invention, compared with a voltage sensor, a current sensor has relatively poor reliability and is easily affected by noise interference. Canceling the current sensor is beneficial to improving system reliability and reducing costs. From Figure 4 the control block diagram of the decoupling controller shown, it can be seen that the inductor current inner loop of the decoupling inductor is crucial for the control of the active power decoupling circuit. Therefore, a current observer needs to be designed. The state equation of the current observer is:

[0076]

[0077] where u, y, are the estimated value of the system state variable, the system input, the system output, and the estimated value of the system output respectively, A, B, and L are the system state matrix, the system input matrix, and the current observer gain matrix respectively, is the difference between the system output and the estimated value of the system output.

[0078] The control block diagram of the Romberg observer is as shown in Figure 5 According to the first relationship and combined with the Romberg observer, an observer mathematical model is obtained, which satisfies the following relationship:

[0079]

[0080] where L is the inductance value of the decoupling inductor, is the estimated value of the inductor current flowing through the decoupling inductor, u c2 is the measured value of the second voltage across the second capacitor, is the estimated value of the second voltage across the second capacitor, u dc is the DC bus voltage, C is the capacitance value of the second capacitor, k1 is the first gain of the Romberg observer, and k2 is the second gain of the Romberg observer.

[0081] Obtain the estimated value of the inductance current of the decoupling inductor based on the mathematical model of the observer

[0082] Continue to refer to Figure 4 , the reference value i of the inductance current of the decoupling inductor Lref and the estimated value of the inductance current Take the difference between them, amplify the difference between the two proportionally through a proportional controller P and control the updated duty cycle d. The duty cycle is the proportion of the on-time of the first switching tube in the control period. According to the updated duty cycle d and in combination with the first relational expression, use the current observer CurrentObserver to cyclically update the estimated value of the inductance current According to the reference value i of the inductance current Lref and the worse estimated value of the inductance current Update the difference between the two, and cyclically update the duty cycle d. In this way, cycle until there is no secondary ripple in the DC bus voltage, that is, the active power decoupling of the DC bus voltage is completed.

[0083] Step S13: Control the on and off of the first switching tube and the second switching tube according to the final duty cycle.

[0084] In the embodiment of the present invention, continue to refer to Figure 4 , process according to the duty cycle using a pulse width modulator PWM to obtain a first control signal S D1 and a second control signal S D2 ; control the on and off of the first switching tube according to the first control signal S D1 , and control the on and off of the second switching tube according to the second control signal S D2 .

[0085] The active power decoupling method of the embodiment of the present invention realizes active power decoupling by adjusting the duty cycle representing the proportion of the on-time of the first switching tube in the control period, avoids current control, and realizes no current sensor, that is, there is no need to use a current sensor to detect the inductance current of the decoupling inductor, which is beneficial to improving the system reliability and reducing the cost.

[0086] The above describes specific embodiments of the present invention. In some cases, the actions or steps recorded in the embodiments of the present invention can be executed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0087] Based on the same concept, an embodiment of the present invention further provides an active power decoupling device, which is applied to a decoupling controller in an active power decoupling circuit. Attached Figure 6 As shown, the active power decoupling device includes: a reference current acquisition module, a duty ratio acquisition module, and a decoupling control module. Among them,

[0088] The reference current acquisition module is configured to extract an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and perform transformation control on the orthogonal signal to obtain a reference value of the inductor current of the decoupling inductor;

[0089] The duty ratio acquisition module is configured to obtain an estimated value of the inductor current of the decoupling inductor by using an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty ratio in the active power decoupling circuit, and cyclically update the duty ratio according to the current difference between the reference value of the inductor current and the estimated value of the inductor current until there is no secondary ripple in the DC bus voltage. The duty ratio is the ratio of the on-time of the first switch tube to the control period;

[0090] The decoupling control module is configured to control the on and off of the first switch tube and the second switch tube according to the final duty ratio.

[0091] For the convenience of description, when describing the above device, various modules are described separately according to their functions. Of course, when implementing the embodiments of the present invention, the functions of each module can be implemented in one or more software and / or hardware.

[0092] The device in the above embodiment is applied to the corresponding method in the foregoing embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be elaborated here.

[0093] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the method described in any one of the above embodiments is implemented.

[0094] An embodiment of the present invention provides a non-volatile computer storage medium, and the computer storage medium stores at least one executable instruction, and the computer executable instruction can execute the method described in any one of the above embodiments.

[0095] Figure 7FIG. 0 shows a more specific schematic diagram of the hardware structure of the electronic device provided in this embodiment. The device may include: a processor 701, a memory 702, an input / output interface 703, a communication interface 704, and a bus 705. Among them, the processor 701, the memory 702, the input / output interface 703, and the communication interface 704 are communicatively connected to each other inside the device through the bus 705.

[0096] The processor 701 may be implemented in the form of a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the method embodiments of the present invention.

[0097] The memory 702 may be implemented in the form of a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 702 may store an operating system and other application programs. When implementing the technical solutions provided in the method embodiments of the present invention through software or firmware, the relevant program codes are stored in the memory 702 and are called and executed by the processor 701.

[0098] The input / output interface 703 is used to connect to an input / output module to implement information input and output. The input / output module may be configured as a component in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Among them, the input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0099] The communication interface 704 is used to connect to a communication module (not shown in the figure) to implement communication interaction between this device and other devices. Among them, the communication module may implement communication in a wired manner (such as USB, network cable, etc.) or in a wireless manner (such as mobile network, WIFI, Bluetooth, etc.).

[0100] The bus 705 includes a path for transmitting information between various components of the device (such as the processor 701, the memory 702, the input / output interface 703, and the communication interface 704).

[0101] It should be noted that although the above device only shows the processor 701, the memory 702, the input / output interface 703, the communication interface 704, and the bus 705, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device may also only include the components necessary to implement the solution of the embodiments of the present invention, and does not necessarily include all the components shown in the figure.

[0102] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is exemplary only and is not intended to imply that the scope of the present application is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present application as described above, which are not provided in detail for the sake of brevity.

[0103] The present application is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the embodiments of the present invention. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of the present invention shall be included within the protection scope of the present application.

Claims

1. An active power decoupling method applied to an active power decoupling circuit, characterized in that the active power decoupling circuit includes: a decoupling controller, a first switching tube, a second switching tube, a decoupling inductor, a first capacitor, and a second capacitor; the first switching tube and the second switching tube are connected in series, the first capacitor and the second capacitor are connected in series, one end of the first switching tube and one end of the first capacitor are connected to the upper output end of the rectifier, and one end of the second switching tube and one end of the second capacitor are connected to the lower output end of the rectifier; the first end of the decoupling inductor is connected between the first switching tube and the second switching tube, and the other end of the decoupling inductor is connected between the first capacitor and the second capacitor; one end of the first capacitor is also connected to the upper input end of the inverter, and one end of the second capacitor is also connected to the lower input end of the inverter to output a DC bus voltage to the inverter; the output end of the decoupling controller is connected to the control ends of the first switching tube and the second switching tube, and the decoupling controller is used to obtain the DC bus voltage output by the active power decoupling circuit and the second voltage across the second capacitor, and control the on / off of the first switching tube and the second switching tube according to the DC bus voltage and the second voltage; the method includes: extracting an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and performing transformation control on the orthogonal signal to obtain a reference value of the inductor current of the decoupling inductor; obtaining an estimated value of the inductor current of the decoupling inductor by applying an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty cycle in the active power decoupling circuit, and cyclically updating the duty cycle according to the current difference between the reference value of the inductor current and the estimated value of the inductor current until there is no secondary ripple in the DC bus voltage, where the duty cycle is the ratio of the on-time of the first switching tube to the control period; the obtaining an estimated value of the inductor current of the decoupling inductor by applying an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty cycle in the active power decoupling circuit includes: obtaining a first relationship between the DC bus voltage, the second voltage across the second capacitor, the duty cycle, and the inductor current value of the decoupling inductor based on the active power decoupling circuit; obtaining an estimated value of the inductor current of the decoupling inductor by applying a Romberg observer according to the first relationship; the obtaining an estimated value of the inductor current of the decoupling inductor by applying a Romberg observer according to the first relationship includes: obtaining an observer mathematical model according to the first relationship in combination with a Romberg observer, satisfying the following relationship: where L is the inductance value of the decoupling inductor, is the estimated value of the inductor current flowing through the decoupling inductor, and u c2 is the measured value of the second voltage across the second capacitor, is the estimated value of the second voltage across the second capacitor, and u dc is the DC bus voltage, C is the capacitance value of the second capacitor, k1 is the first gain of the Luenberger observer, and k2 is the second gain of the Luenberger observer; obtaining the estimated value of the inductor current of the decoupling inductor based on the observer mathematical model; controlling the on / off of the first switching tube and the second switching tube according to the final duty cycle.

2. The method according to claim 1, characterized in that, the extracting an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit includes: subtracting the DC bus voltage from the DC bus reference voltage to obtain a voltage difference between the two; The second-order generalized integrator is used to process the voltage difference and extract the orthogonal signal.

3. The method according to claim 1, characterized in that, The obtaining of the reference inductor current of the decoupling inductor by performing transformation control on the orthogonal signal includes: Performing a rotation transformation on the orthogonal signal to obtain the ripple reference value of the second voltage; Processing the ripple reference value by applying a proportional-resonant controller to obtain the reference inductor current of the decoupling inductor.

4. The method according to claim 1, characterized in that, The controlling the on / off of the first switch tube and the second switch tube according to the final duty ratio includes: Processing according to the duty ratio by applying a pulse width modulator to obtain a first control signal and a second control signal; Controlling the on / off of the first switch tube according to the first control signal and controlling the on / off of the second switch tube according to the second control signal.

5. An active power decoupling device applied to an active power decoupling circuit, characterized in that the active power decoupling circuit includes: a decoupling controller, a first switch tube, a second switch tube, a decoupling inductor, a first capacitor, and a second capacitor; the first switch tube and the second switch tube are connected in series, the first capacitor and the second capacitor are connected in series, one end of the first switch tube and one end of the first capacitor are connected to the upper output end of the rectifier, and one end of the second switch tube and one end of the second capacitor are connected to the lower output end of the rectifier; the first end of the decoupling inductor is connected between the first switch tube and the second switch tube, and the other end of the decoupling inductor is connected between the first capacitor and the second capacitor; one end of the first capacitor is further connected to the upper input end of the inverter, and one end of the second capacitor is further connected to the lower input end of the inverter to output a DC bus voltage to the inverter; the output end of the decoupling controller is connected to the control ends of the first switch tube and the second switch tube, and the decoupling controller is used to obtain the DC bus voltage output by the active power decoupling circuit and the second voltage across the second capacitor, and control the on / off of the first switch tube and the second switch tube according to the DC bus voltage and the second voltage; the device includes: a reference current acquisition module, configured to extract an orthogonal signal by using a second-order generalized integrator according to the DC bus voltage of the active power decoupling circuit, and perform transformation control on the orthogonal signal to obtain the reference inductor current of the decoupling inductor; a duty ratio acquisition module, configured to obtain an estimated value of the inductor current of the decoupling inductor by applying an observer according to the DC bus voltage, the second voltage across the second capacitor, and the duty ratio in the active power decoupling circuit, and cyclically update the duty ratio according to the current difference between the reference inductor current and the estimated inductor current until there is no second-order ripple in the DC bus voltage, where the duty ratio is the proportion of the on-time of the first switch tube in the control period; Obtaining an estimated value of the decoupling inductor current according to the DC bus voltage, the second voltage across the second capacitor, and the duty cycle in the active power decoupling circuit includes: obtaining a first relationship between the DC bus voltage, the second voltage across the second capacitor, the duty cycle, and the inductor current value of the decoupling inductor based on the active power decoupling circuit; obtaining the estimated value of the decoupling inductor current by applying a Romberg observer according to the first relationship; The obtaining the estimated value of the decoupling inductor current by applying a Romberg observer according to the first relationship includes: obtaining an observer mathematical model according to the first relationship in combination with a Romberg observer, which satisfies the following relationship: where, L is the inductance value of the decoupling inductor, is the estimated value of the inductor current flowing through the decoupling inductor, u c2 is the measured value of the second voltage across the second capacitor, is the estimated value of the second voltage across the second capacitor, u dc is the DC bus voltage, C is the capacitance value of the second capacitor, k1 is the first gain of the Luenberger observer, and k2 is the second gain of the Luenberger observer; obtaining the estimated value of the inductor current of the decoupling inductor based on the observer mathematical model; A decoupling control module is configured to control the on / off of the first switch tube and the second switch tube according to the final duty cycle.

6. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, the method described in any one of claims 1-4 is implemented.

7. A computer storage medium, characterized in that, At least one executable instruction is stored in the storage medium, and the executable instruction causes the processor to execute the method described in any one of claims 1-4.

Images