Low ripple and high gain inverter topology with magnetically integrated coupled inductor and its control method

Abstract

The present invention discloses a low-ripple, high-gain inverter topology with magnetically integrated coupled inductors and a control method thereof. The inverter topology includes a power supply, wherein the positive electrode of the power supply is electrically connected to a first magnetically integrated coupled inductor, a second magnetically integrated coupled inductor, and a third magnetically integrated coupled inductor; the second magnetically integrated coupled inductor is electrically connected to a first half-bridge circuit, and the third magnetically integrated coupled inductor is electrically connected to a second half-bridge circuit; the first half-bridge circuit is electrically connected to one end of a fourth capacitor via a first filter circuit, and the second half-bridge circuit is electrically connected to the other end of the fourth capacitor via a second filter circuit; and the fourth capacitor is electrically connected to a load via a full-bridge circuit. The present invention achieves high-gain voltage conversion and single-stage energy conversion, as well as input and output current ripple suppression, thereby improving electromagnetic compatibility performance; reduces high-frequency common-mode voltage fluctuations to achieve leakage current suppression, reduces the power level of the switch and the total energy stored in the passive components, improves power density and efficiency, and reduces overall cost and volume.

Description

Technical Field

[0001] The present invention relates to the field of electricity, and in particular to a low-ripple high-gain inverter topology with magnetically integrated coupled inductors and a control method thereof. Background Art

[0002] Photovoltaic power generation systems have the problem of low terminal voltage. There are many ways to solve this problem. One of them is to use multiple photovoltaic modules in series to increase the terminal voltage of the photovoltaic system. However, on cloudy days, the photovoltaic panels cannot operate at the maximum power point, resulting in a wide range of changes in the terminal voltage of the photovoltaic system. Another method is to use an isolated inverter with a step-up transformer, but this will increase the volume, weight and cost of the entire system, thereby reducing power density and efficiency. In addition, Figure 1 As shown in the figure, a cascaded non-isolated inverter is also a commonly used boost method. The maximum power is tracked by the front-stage Buck-Boost converter, and the DC bus voltage is converted into a stable AC output through the inverter. However, this requires two-stage energy conversion, which increases the complexity of control and the efficiency is still low. Summary of the Invention

[0003] The object of the present invention is to provide a low-ripple, high-gain inverter topology with magnetically integrated coupled inductors and a control method thereof, so as to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A low ripple high gain inverter topology with magnetic integrated coupled inductor, including power supply ,power supply The positive electrode is electrically connected to the first magnetic integrated coupled inductor The same-name terminal and the second magnetic integrated coupled inductor The same-name terminal; power supply The negative pole is electrically connected to the third magnetic integrated coupled inductor The non-identical end of the second magnetic integrated coupled inductor The non-identical end of the first half-bridge circuit is electrically connected to the midpoint of the first half-bridge circuit, and the third magnetic integrated coupled inductor is electrically connected to the midpoint of the first half-bridge circuit. The same-name end is electrically connected to the midpoint of the second half-bridge circuit; the first magnetic integrated coupled inductor The non-identical end of the first ripple current suppression capacitor is electrically connected to One end of the first ripple current suppression capacitor The other end is connected to the power supply The first half-bridge circuit is electrically connected to the fourth capacitor through the first filter circuit The second half-bridge circuit is electrically connected to the fourth capacitor through the second filter circuit. The other end of the fourth capacitor Electrically connect the load via a full-bridge circuit .

[0006] Further improvement, the first half-bridge circuit includes a first switch tube S 1. The first switch tube S 1. The source is electrically connected to the power supply The negative electrode of the first switch tube S 1 The drain is electrically connected to the second magnetic integrated coupled inductor The non-same-name terminal and the third switch tube S 3's source, the third switch S The drain of 3 is electrically connected to the first filtering circuit.

[0007] Further improvement, the first filter circuit includes a second capacitor , the second capacitor One end is electrically connected to the first switch tube S 1 source, the second capacitor The other end is electrically connected to the third switch tube S 3 drain and first fully coupled inductor The first fully coupled inductor The non-identical end of the fourth capacitor is electrically connected to one end.

[0008] Further improvement, the second half-bridge circuit includes a second switch tube S 2. Second switch tube S The source of 2 is electrically connected to the third magnetic integrated coupled inductor The same-name terminal and the fourth switch tube S 4's drain; the fourth switch tube S The source of 4 is electrically connected to the second filtering circuit.

[0009] Further improvement, the second filtering circuit includes a third capacitor , the third capacitor One end is electrically connected to the fourth switch tube S 4 source and the second fully coupled inductor The non-identical end of the third capacitor The other end is electrically connected to the second switch tube S 2 drain and power supply The positive pole of the second fully coupled inductor The same-name end is electrically connected to the fourth capacitor the other end.

[0010] Further improvement, the full-bridge circuit includes a fifth switch tube S 5. The fifth switch tube SThe drain of 5 is electrically connected to the fourth capacitor One end and the seventh switch tube S 7's drain, the fifth switch S The source of 5 is electrically connected to the sixth switch tube S 6 drain and the sixth magnetic integrated coupled inductor The same-name terminal, the sixth switch tube S The source of 6 is electrically connected to the fourth capacitor The other end and the eighth switch tube S 8 source, the eighth switch tube S The drain of 8 is electrically connected to the seventh switch tube S 7 source, fifth ripple current suppression capacitor One end and the load One end of the fifth ripple current suppression capacitor The other end is electrically connected to the fifth magnetic integrated coupled inductor The fifth magnetic integrated coupled inductor The non-identical terminals are electrically connected to the sixth magnetic integrated coupled inductor Non-identical terminals and loads the other end.

[0011] A further improvement is that the second magnetic integrated coupled inductor and the third magnetic integrated coupled inductor Fully coupled setup; first fully coupled inductor and the second fully coupled inductor Fully coupled setup.

[0012] A further improvement is that the first magnetic integrated coupled inductor Self-inductance value L 1 , the second magnetic integrated coupled inductor Self-inductance value L 2 , the third magnetic integrated coupled inductor Self-inductance value L 3 、Fifth magnetic integrated coupled inductor Self-inductance value L 5 、The sixth magnetic integrated coupled inductor Self-inductance value L 6 、 The first magnetic integrated coupled inductor Integrated coupled inductor with second magnetic Mutual inductance , the first magnetic integrated coupled inductor Integrated coupled inductor with third magnetic Mutual inductance ， Second magnetic integrated coupled inductor Integrated coupled inductor with third magnetic Mutual inductance ; Fifth magnetic integrated coupled inductor Integrated coupled inductor with the sixth magnetic Mutual inductance Satisfies the following formula:

[0013] (19)

[0014] (20)

[0015] (twenty one)

[0016] in, The first magnetic integrated coupled inductor Integrated coupled inductor with second magnetic mutual induction; For the second magnetic integrated coupled inductor Integrated coupled inductor with third magnetic The mutual induction, The fifth magnetic integrated coupled inductor Integrated coupled inductor with the sixth magnetic mutual induction; The sixth magnetic integrated coupled inductor self-perception;

[0017] Coupled inductors , coupled inductors , coupled inductors , coupled inductors , coupled inductors , coupled inductors The current ripple size on For power supply The voltage across the terminals, is the voltage gain of the inverter topology, is the duty cycle of the switch, and the duty cycles of the switching tubes are the same;

[0018] First ripple current suppression capacitor Capacitance C 1 , the second capacitor Capacitance C 2 , the third capacitor Capacitance C 3 , the fourth capacitor Capacitance C4 and the fifth ripple current suppression capacitor Capacitance C 5 Satisfies the following formula:

[0019] (twenty two)

[0020] (twenty three)

[0021] in, The first ripple current suppression capacitor , the second capacitor , the third capacitor , the fourth capacitor and the fifth ripple current suppression capacitor The voltage ripple size on is the size of the output load;

[0022] First fully coupled inductor and the second fully coupled inductor Total inductive reactance , and satisfy:

[0023] (twenty four)

[0024] in The first fully coupled inductor The feeling value, The second fully coupled inductor The feeling value, The first fully coupled inductor With the second fully coupled inductor Mutual inductance ， is the switching frequency.

[0025] A control method for a low-ripple, high-gain inverter topology with magnetically integrated coupled inductors, wherein the low-ripple, high-gain inverter topology with magnetically integrated coupled inductors operates symmetrically in the positive and negative half cycles within a power frequency cycle, wherein in the positive half cycle, the seventh switch tube S 7 remains closed, the eighth switch tube S 8 is continuously turned on, at this time the output voltage Greater than zero, when the power Voltage across both ends When working in Buck mode, the first switch tube S 1 and the second switch tube S 2 remains closed, the third switch tube S 3 and the fourth switch tube S 4 is continuously turned on, the fifth switch tube S 5 and the sixth switch tubeS 6 High frequency complementary work, power supply V The energy is delivered to the load through a single-stage conversion in buck mode ;when When the converter works in Boost mode, the fifth switch tube S 5 is continuously open, the sixth switch tube S 6 remains closed, the first switch tube S 1 and the second switch tube S 2 are connected to the third switch tube S 3 and the fourth switch tube S 4 fully complementary work, power supply The energy is transferred to the load through a single-stage conversion in boost mode. ;

[0026] In the negative half cycle, the seventh switch tube S 7 is continuously open, the eighth switch tube S 8 remains closed, the output voltage Less than zero, when When working in Buck mode, the first switch tube S 1 and the second switch tube S 2 remains closed, the third switch tube S 3 and the fourth switch tube S 4 is continuously turned on, the fifth switch tube S 5 and the sixth switch tube S 6 High frequency complementary work, power supply The energy is delivered to the load through a single-stage conversion in buck mode ;when When the converter works in Boost mode, the fifth switch tube S 5 remains closed, the sixth switch tube S 6Continuously open, the first switch tube S 1 and the second switch tube S 2 are connected to the third switch tube S 3 and the fourth switch tube S 4 fully complementary work, power supply The energy is transferred to the load through a single-stage conversion in boost mode. .

[0027] Further improvement is to work in mode 1, mode 2, mode 3 and mode 4 in sequence in the positive half cycle;

[0028] In mode 1, the first switch S 1. Second switch tube S 2. Sixth switch tube S 6 and the seventh switch tube S 7 is closed, the third switch tubeS 3. The fourth switch tube S 4. The fifth switch tube S 5 and the eighth switch tube S 8 is turned on; the duration of mode 1 is The fifth switch S 5 duty cycle, is the switching cycle of the switch tube;

[0029] In mode 2, the first switch S 1. Second switch tube S 2. The fifth switch tube S 5 and the seventh switch tube S 7 is closed, the third switch tube S 3. The fourth switch tube S 4. Sixth switch tube S 6 and the eighth switch tube S 8 is turned on, the duration of mode 2 is ;

[0030] In mode 3, the third switch tube S 3. The fourth switch tube S 4. Sixth switch tube S 6 and the seventh switch tube S 7 is closed, the first switch tube S 1. Second switch tube S 2. The fifth switch tube S 5 and the eighth switch tube S 8 is turned on; the duration of mode 3 is

[0031] In mode 4, the first switch tube S 1. Second switch tube S 2. The sixth switch tube S 6 and the seventh switch tube S 7 is closed, the third switch tube S 3. The fourth switch tube S 4. The fifth switch tube S 5 and the eighth switch tube S 8 is turned on; the duration of mode 4 is The first switch S 1 and the second switch tube S 2 duty cycle.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) This invention proposes a low-ripple, high-gain inverter topology and control method using magnetically integrated coupled inductors. The topology includes an inverter structure and a sinusoidal modulation strategy for the inverter's output voltage. The topology is a single-stage energy conversion system that converts a DC input into positive and negative AC outputs. The use of magnetically integrated coupled inductors reduces the size of the inverter, suppresses current ripple at both the input and output terminals, and improves the inverter's power density and efficiency.

[0034] (2) For the proposed inverter, a design and calculation method for the relevant power device parameters is proposed, including the selection of the self-inductance and mutual inductance of the coupled inductors L1*-L3* and L5*-L6*, the capacitance range of the capacitors C1*-C5*, and the winding structure design of the coupled inductors, which reduces the high-frequency common-mode voltage fluctuation and achieves the suppression of leakage current and input and output ripple current.

[0035] By using the method of the present invention, the high-frequency voltage ripples inevitably generated at the input and output ends of the inverter when using pulse width modulation technology are suppressed. The single-phase inverter has a high-gain buck-boost regulation capability and can achieve a stable AC voltage output when the input voltage is low and fluctuates. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of a two-stage non-isolated converter in a traditional solution.

[0037] Figure 2 This is a topology diagram of the low-ripple, high-gain inverter with magnetically integrated coupled inductors proposed in the present invention.

[0038] Figure 3 This is a schematic diagram of the modulation strategy of the low-ripple, high-gain inverter with magnetically integrated coupled inductors proposed in the present invention.

[0039] FIG4( a ) is a schematic diagram of the working mode of the inverter proposed in the present invention in the positive half-cycle mode 1 of the power frequency period.

[0040] FIG4( b ) is a schematic diagram of the working mode of the inverter proposed in the present invention in the positive half-cycle mode 2 of the power frequency period.

[0041] FIG4( c ) is a schematic diagram of the working mode of the inverter proposed in the present invention in the positive half-cycle mode 3 of the power frequency period.

[0042] FIG4( d ) is a schematic diagram of the working mode of the inverter proposed in the present invention in the positive half-cycle mode 4 of the power frequency period.

[0043] Figure 5 The voltage gain of the inverter proposed by the present invention varies with the duty cycle. D Schematic diagram of the changing curve.

[0044] Figure 6Schematic diagram of the coupled inductor winding structure of the inverter proposed in the present invention, wherein (a) is the winding structure of the first magnetic integrated coupled inductor, the second magnetic integrated coupled inductor, and the third magnetic integrated coupled inductor; (b) is the winding structure of the first fully coupled inductor and the second fully coupled inductor; and (c) is the winding structure of the fifth magnetic integrated coupled inductor and the sixth magnetic integrated coupled inductor.

[0045] Figure 7 This is a simplified common-mode circuit diagram of the inverter proposed in the present invention.

[0046] FIG8( a ) is a waveform diagram of the input current of the inverter proposed in the present invention when the input voltage changes.

[0047] FIG8( b ) is a waveform diagram of the output current of the inverter proposed in the present invention when the input voltage changes.

[0048] FIG8( c ) is a waveform diagram of the output voltage of the inverter proposed in the present invention when the input voltage changes. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] like Figure 2 As shown, the present invention proposes a low ripple high gain inverter with magnetic integrated coupled inductor, including eight power switching devices S 1- S 8. Magnetic integrated coupled inductor and (Their self-inductance values ​​are L 1. L 2. L 3. L 5 and L 6, the mutual inductance values ​​are 、 、 and ), fully coupled inductor and (Their self-inductance values ​​are and , the mutual inductance is ), ripple current suppression capacitor and (The values ​​are C 1 and C 5) Filter capacitor 、 (The values ​​are C 2 and C 3) and DC support capacitor (Its value is C 4). Coupled inductor and It is fully coupled, and its self-inductance and mutual inductance are the same. and The capacitance value is the same. Coupled inductor 、 The same-name end is connected to the positive pole of the power supply. The non-identical end of S 1. S 3 constitutes the midpoint of the half bridge, The non-identical end is connected to the negative pole of the power supply, and the identical end is connected to the S 2. S 4 constitutes the midpoint of the half bridge. The two ends are connected to The non-identical terminal and the negative terminal of the power supply. S 1 The source is connected to the negative pole of the power supply, S 2. The drain is connected to the positive terminal of the power supply. Connect both ends to S 3. Drain and negative power supply, Connect both ends to the positive pole of the power supply and S 4 Source. The end of the same name is connected to S 3Drain, opposite end and capacitor connected, The same-name terminal and capacitor The other end is connected to S 4 Source. Both ends are connected to S 5- S 8 constitutes a full-bridge circuit, The same-name end is connected to the bridge arm S 5- S The midpoint of 6, The end of the same name is connected to , The other end is connected to the bridge arm S 7- S The midpoint of 8, and The non-identical end and S 7- S The midpoint between 8 is the inverter output.

[0051] The control method of the low ripple high gain inverter topology proposed in this embodiment is as follows:

[0052] like Figure 3 As shown in Figure 1, in one power frequency cycle, the inverter operates symmetrically in the positive and negative half cycles. In the positive half cycle, S 7 keep it closed, S 8 is continuously turned on, at this time the output voltage Greater than zero. When the converter works in Buck mode, S 1 and S 2Continuous opening, S 3 and S 4Keep it closed. S 5 and S 6 high frequency complementary operation. The energy of the input source is transferred to the output end through a single-stage conversion in buck mode. When the converter works in Boost mode, S 5Continuous opening, S 6 Keep it closed, S 1 and S 2 are both high frequency switching tubes and S 3 and S 4 fully complementary work, the energy of the input source is transferred to the output end through a single-stage conversion in the boost mode. In the negative half cycle, S 7Continuous opening, S 8 remains closed, the output voltage Less than zero, switching device S 1- S 6 The working mode is similar to the positive half cycle. Because the positive half cycle and the negative half cycle are symmetrical, only the working mode of the positive half cycle is analyzed here.

[0053] Mode 1: As shown in Figure 4 (a), at this time S 1, S 2, S 6 and S 7 closed, S 3, S 4, S 5, S 8 is turned on. The input source passes through the inductor 、 、 and Energy is transferred, at this time the capacitor 、 and It also provides energy to the output side. Current on and The ripple slope is opposite and The average value of is zero, which means that the output current can achieve zero ripple. The ripple current comes from and ,Depend on and The first-order filter network formed by The current ripple in the 、 and The current ripple of the input current can be ignored, so the input current ripple close to zero can be achieved. The voltage balance equation is as follows:

[0054] (1)

[0055] in 、 、 、 and is the corresponding mutual inductance.

[0056] During this period, the capacitor The voltage remains approximately constant because the capacitor voltage cannot change suddenly. Therefore, the following equation is obtained:

[0057] (2)

[0058] From formula (1) and formula (2), we can get:

[0059] (3)

[0060] According to formula (3), we can get and The current ripple is shown in formula (4).

[0061] (4)

[0062] Mode 2: As shown in Figure 4 (b), at this time S 1, S 2, S 5 and S 7 closed, S 3, S 4, S 6, S 8 is turned on. The input source passes through the inductor 、 、 and Towards capacitance 、 and Transfer energy, inductance Current on pass S 6 and S 8 Freewheeling. Coupled inductor Current on and The ripple slope is opposite and The average value of is zero, so the output current ripple can be achieved. The voltage balance equation is as follows:

[0063] (5)

[0064] capacitance The charging current on ,Depend on and The first-order filter network formed by The current ripple in is close to zero, which means 、 and The current ripple of the capacitor can be ignored, so the input current ripple can be close to zero. The voltage remains approximately constant because the capacitor voltage cannot change suddenly. Therefore, the following equation is obtained:

[0065] (6)

[0066] From formula (5) and formula (6), we can get:

[0067] (7)

[0068] According to formula (7), we can get and The current ripple is shown in (8).

[0069] (8)

[0070] In Buck mode, the durations of Mode 1 and Mode 2 are and , yes S 5 switching cycles, yes S 5 duty cycle. In one switching cycle, the inductor is balanced in volt-seconds and the capacitor is balanced in ampere-seconds. According to equations (3) and (7), the voltage gain of the Buck mode is It can be obtained as:

[0071] (9)

[0072] Mode 3: As shown in Figure 4 (c), at this time S 3, S 4, S 6 and S 7 closed, S 1,S 2, S 5, S 8 is turned on. Input source is through S 1 and S 2-way separate inductors and Transfer energy while capacitor 、 and It also provides energy to the output side. Current on and The ripple slope is opposite and The average value of is zero, which means that zero output current ripple can be achieved. and The total ripple current on The ripple slope is opposite and The mean value of is zero, and The first-order filter network formed by The current ripple in is close to zero, which means and The current ripple in the input voltage can be ignored, so the input current ripple can be approximated to zero. The voltage balance equation is shown in equation (10):

[0073] (10)

[0074] During this period, the capacitor The voltage of the capacitor remains approximately constant because the capacitor voltage cannot change suddenly, so:

[0075] (11)

[0076] From formula (10) and formula (11), we can get:

[0077] (12)

[0078] in, for and Self-perception, for and and Mutual induction between.

[0079] According to formula (12), we can get and The current ripple is shown in formula (13).

[0080] (13)

[0081] Mode 4: As shown in Figure 4 (d), at this time S 1, S 2, S 6 and S 7 closed, S 3, S 4, S 5, S 8 is turned on. The input source passes through the inductor 、 、 and Towards capacitance 、 and and output side to transfer energy, coupled inductor Current on and The ripple slope is opposite and The average value of is zero, which means that zero output current ripple can be achieved. and The total ripple current on The ripple slope is opposite and The mean value of is zero, The charging current comes from ,Depend on and The first-order filter network formed by The current ripple in is close to zero, which means and The current ripple in can be ignored, so the input current ripple can be approximated to zero. The voltage balance equation is shown in Equation (14).

[0082] (14)

[0083] Similarly, during this period, the capacitor The voltage of the capacitor remains approximately constant because the capacitor voltage cannot change suddenly, so:

[0084] (15)

[0085] From formula (14) and formula (15), we can get:

[0086] (16)

[0087] According to formula (16), we can get and The current ripple is shown in formula (17).

[0088] (17)

[0089] In Boost mode, the duration of Mode 3 and Mode 4 are and , yes S 1 and

[0090] S 2 switching cycles, yes S 1 duty cycle. In one switching cycle, the inductor is balanced in volt-seconds and the capacitor is balanced in ampere-seconds. According to equations (12) and (16), the voltage gain of the boost mode is It can be obtained as:

[0091] (18)

[0092] From equations (9) and (18), we can see that the inverter gain varies with the operating mode and duty cycle. D The gain curve of the inverter changes with the change of Figure 5 In Boost mode, this topology has high gain and is suitable for applications where the input voltage fluctuates significantly.

[0093] The present invention provides a method for calculating and designing parameters of a low-ripple high-gain inverter with magnetic integrated coupled inductors, including coupled inductors 、 and and capacitors .

[0094] Defining coupled inductors and Self-perception ( L 1, L 2, L 3, L 5, L 6) and mutual inductance ( , , , )as follows:

[0095] (19)

[0096] The selection of the inductor value depends on the allowable current ripple. According to equations (3) and (12), the inductor The current ripple in can be obtained by the following formula:

[0097] (20)

[0098] (twenty one)

[0099] The selection of capacitor value depends on the allowed capacitor voltage ripple. The voltage ripple on the MOSFET is as follows:

[0100] (twenty two)

[0101] (twenty three)

[0102] Considering the allowable inductor current ripple and capacitor voltage ripple, from equations (21), (22), (23) and (24), we can get L 1- L 3. L 5- L 6 and C 1- C The value of 5.

[0103] By coupled inductor and capacitors First-order Low-pass filter network, when Total inductive reactance Significantly greater than The capacitive reactance is usually ten times or more. The current ripple in can be reduced to almost zero, that is:

[0104] (twenty four)

[0105] In the above formula, is the switching frequency, is the voltage gain of the inverter, is the input voltage of the inverter, The inverter output load size.

[0106] The winding structure of the proposed coupled inductor is as follows: Figure 6 As shown, and is a fully coupled inductor with the same number of turns, and It is also a fully coupled inductor with the same number of turns. Self-perception and Relative to and The mutual inductance is the same, The winding and and The windings are wound on both sides of the core. and The windings are also wound on both sides of the magnetic core.

[0107] The present invention also provides a method for suppressing leakage current. Figure 7 The figure shows the simplified common mode circuit of the inverter, where The equivalent inductance from the terminal to ground is , its value ,from The equivalent inductance from the terminal to ground is , its value In the proposed inverter, Duanhe End to The voltage at the terminal is defined as and (The values ​​are and ), so the common-mode voltage and differential mode voltage Value and It can be expressed as:

[0108] (25)

[0109] (26)

[0110] The common-mode voltage and differential-mode voltage in the inverter will affect the leakage current. According to equations (25) and (26), the total common-mode voltage Value As shown below:

[0111] (27)

[0112] In this case, when hour, ,when 0 o'clock, .Depend on 、 、 、 and The voltage circuit composed of the following formula can be obtained:

[0113] (28)

[0114] Because there is and , we can get the following equation:

[0115] (29)

[0116] Therefore, the leakage current depends on the capacitance The voltage ripple on the capacitor is , the equivalent common-mode capacitance is The leakage current caused by capacitor voltage ripple is calculated as follows:

[0117] (30)

[0118] in, It is a capacitor The power frequency voltage ripple component, is the output voltage cycle, It is a capacitor The high-frequency voltage ripple component. The change is slow and its effect on leakage current can be ignored. The leakage current depends on the high frequency component Therefore, from equations (28), (29), and (30), the leakage current caused by capacitor voltage ripple can be calculated as:

[0119] (31)

[0120] When other circuit parameters are constant, choose to increase The capacitance value can suppress the leakage current, compared with the expected leakage current size, while considering cost, size and reliability, The capacitance value can be selected according to the actual application.

[0121] As shown in Figure 8(a), the circuit simulation results show that when the input voltage fluctuates, the low ripple high gain buck-boost single-phase inverter proposed in this invention can achieve a stable AC voltage output. Figure 8(b) shows the input current, magnetic integrated coupled inductor and The current waveform on the topology shows that the input current ripple is suppressed; Figure 8(c) shows And the waveform of the output current, it can be seen that the topology achieves the suppression of output current ripple.

[0122] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A low ripple and high gain inverter topology with magnetically integrated coupled inductors, characterized in that: Power supply included ,power supply The positive electrode is electrically connected to the first magnetic integrated coupled inductor The same-name terminal and the second magnetic integrated coupled inductor The same-name terminal; power supply The negative pole is electrically connected to the third magnetic integrated coupled inductor The non-same-name end; the second magnetic integrated coupled inductor The non-identical end of the first half-bridge circuit is electrically connected to the midpoint of the first half-bridge circuit, and the third magnetic integrated coupled inductor is electrically connected to the midpoint of the first half-bridge circuit. The same-name end is electrically connected to the midpoint of the second half-bridge circuit; the first magnetic integrated coupled inductor The non-identical end of the first ripple current suppression capacitor is electrically connected to One end of the first ripple current suppression capacitor The other end is connected to the power supply The first half-bridge circuit is electrically connected to the fourth capacitor through the first filter circuit The second half-bridge circuit is electrically connected to the fourth capacitor through the second filter circuit. The other end of the fourth capacitor Electrically connect the load via a full-bridge circuit ; The first half-bridge circuit includes a first switch tube ( S 1), the first switch tube ( S 1) The source is electrically connected to the power supply The negative electrode of the first switch tube ( S 1 ) is electrically connected to the drain of the second magnetic integrated coupled inductor The non-identical terminal and the third switch tube ( S 3) source, the third switch tube ( S 3) The drain is electrically connected to the first filter circuit; The first filtering circuit includes a second capacitor , the second capacitor One end is electrically connected to the first switch tube ( S 1) The source, the second capacitor The other end is electrically connected to the third switch tube ( S 3) The drain and first fully coupled inductor The first fully coupled inductor The non-identical end of the fourth capacitor is electrically connected to one end.

2. The low ripple and high gain inverter topology with magnetically integrated coupled inductors according to claim 1, wherein: The second half-bridge circuit includes a second switch tube ( S 2), the second switch tube ( S 2) The source is electrically connected to the third magnetic integrated coupled inductor The same-name terminal and the fourth switch tube ( S 4) drain; the fourth switch tube ( S 4) The source is electrically connected to the second filtering circuit.

3. The low ripple and high gain inverter topology with magnetically integrated coupled inductors according to claim 2, wherein: The second filtering circuit includes a third capacitor , the third capacitor One end is electrically connected to the fourth switch tube ( S 4) The source and the second fully coupled inductor The non-identical end of the third capacitor The other end is electrically connected to the second switch tube ( S 2) Drain and power supply The positive electrode; Second fully coupled inductor The same-name end is electrically connected to the fourth capacitor the other end.

4. The low ripple and high gain inverter topology with magnetically integrated coupled inductors according to claim 3, wherein: The full-bridge circuit includes a fifth switch tube ( S 5), the fifth switch tube ( S 5) The drain is electrically connected to the fourth capacitor One end and the seventh switch tube ( S 7) drain, the fifth switch tube ( S 5) The source is electrically connected to the sixth switch tube ( S 6) The drain and sixth magnetic integrated coupled inductor The same-name terminal, the sixth switch tube ( S 6) The source is electrically connected to the fourth capacitor The other end and the eighth switch tube ( S 8) source, the eighth switch tube ( S 8) The drain is electrically connected to the seventh switch tube ( S 7) Source, fifth ripple current suppression capacitor One end and the load One end of the fifth ripple current suppression capacitor The other end is electrically connected to the fifth magnetic integrated coupled inductor The fifth magnetic integrated coupled inductor The non-identical terminals are electrically connected to the sixth magnetic integrated coupled inductor Non-identical terminals and loads the other end.

5. The low ripple and high gain inverter topology with magnetic integrated coupled inductor according to claim 4, characterized in that: The second magnetic integrated coupled inductor and the third magnetic integrated coupled inductor Fully coupled setup; first fully coupled inductor and the second fully coupled inductor Fully coupled setup.

6. The low ripple and high gain inverter topology with magnetically integrated coupled inductors according to claim 4, characterized in that: The first magnetic integrated coupled inductor Self-inductance value L 1 , the second magnetic integrated coupled inductor Self-inductance value L 2 , the third magnetic integrated coupled inductor Self-inductance value L 3 、Fifth magnetic integrated coupled inductor Self-inductance value L 5 、The sixth magnetic integrated coupled inductor Self-inductance value L 6 、 The first magnetic integrated coupled inductor Integrated coupled inductor with second magnetic Mutual inductance , the first magnetic integrated coupled inductor Integrated coupled inductor with third magnetic Mutual inductance ， Second magnetic integrated coupled inductor Integrated coupled inductor with third magnetic Mutual inductance ; Fifth Magnetic Integrated Coupled Inductor Integrated coupled inductor with the sixth magnetic Mutual inductance Satisfies the following formula: （19）； （20）； （21）； in, The first magnetic integrated coupled inductor Integrated coupled inductor with second magnetic mutual induction; For the second magnetic integrated coupled inductor Integrated coupled inductor with third magnetic The mutual induction, The fifth magnetic integrated coupled inductor Integrated coupled inductor with the sixth magnetic mutual induction; The sixth magnetic integrated coupled inductor self-perception; Coupled inductors , coupled inductors , coupled inductors , coupled inductors , coupled inductors , coupled inductors The current ripple size on For power supply The voltage across the terminals, is the voltage gain of the inverter topology, is the duty cycle of the switch, and the duty cycles of the switching tubes are the same; First ripple current suppression capacitor Capacitance C 1 , the second capacitor Capacitance C 2 , the third capacitor Capacitance C 3 , the fourth capacitor Capacitance C 4 and the fifth ripple current suppression capacitor The capacitance value of the C 5 Satisfies the following formula: （22）； （23）； in, The first ripple current suppression capacitor , the second capacitor , the third capacitor , the fourth capacitor and the fifth ripple current suppression capacitor The voltage ripple size on is the size of the output load; First fully coupled inductor and the second fully coupled inductor Total inductive reactance , and satisfy: ； in L 4a The first fully coupled inductor The feeling value, L 4b The second fully coupled inductor The feeling value, M 4ab The first fully coupled inductor With the second fully coupled inductor Mutual inductance ， is the switching frequency.

7. A control method for a low ripple and high gain inverter topology with magnetically integrated coupled inductors, characterized in that: In one power frequency cycle, the low ripple high gain inverter topology with magnetic integrated coupled inductor according to any one of claims 4 to 6 operates symmetrically in the positive and negative half cycles, wherein in the positive half cycle, the seventh switch tube ( S 7) Keep closed, the eighth switch tube ( S 8) Continuously open, the output voltage Greater than zero, when the power Voltage across both ends When working in Buck mode, the first switch tube ( S 1) and the second switch tube ( S 2) Keep closed, the third switch tube ( S 3) and the fourth switch tube ( S 4) Continuously open, the fifth switch tube ( S 5) and the sixth switch tube ( S 6) High frequency complementary work, power supply The energy is delivered to the load through a single-stage conversion in buck mode ;when When the converter works in Boost mode, the fifth switch tube ( S 5) Continuously open, the sixth switch tube ( S 6) Keep closed, the first switch tube ( S 1) and the second switch tube ( S 2) Both with the third switch tube ( S 3) and the fourth switch tube ( S 4) Fully complementary work, power supply The energy is transferred to the load through a single-stage conversion in boost mode. ; In the negative half cycle, the seventh switch tube ( S 7) Continuously open, the eighth switch tube ( S 8) Keep closed, then the output voltage Less than zero, when When working in Buck mode, the first switch tube ( S 1) and the second switch tube ( S 2) Keep closed, the third switch tube ( S 3) and the fourth switch tube ( S 4) Continuously open, the fifth switch tube ( S 5) and the sixth switch tube ( S 6) High frequency complementary work, power supply The energy is delivered to the load through a single-stage conversion in buck mode ;when When the converter works in Boost mode, the fifth switch tube ( S 5) Keep closed, the sixth switch tube ( S 6) Continuously open, the first switch tube ( S 1) and the second switch tube ( S 2) Both with the third switch tube ( S 3) and the fourth switch tube ( S 4) Fully complementary work, power supply The energy is transferred to the load through a single-stage conversion in boost mode. .

8. The control method of the low ripple and high gain inverter topology with magnetic integrated coupled inductor according to claim 7, characterized in that: Then, in the positive half cycle, it works in mode 1, mode 2, mode 3 and mode 4 in sequence; In mode 1, the first switch tube ( S 1) The second switch tube ( S 2) The sixth switch tube ( S 6) and the seventh switch tube ( S 7) Close, the third switch tube ( S 3) The fourth switch tube ( S 4) The fifth switch tube ( S 5) and the eighth switch tube ( S 8) Open; the duration of mode 1 is For the fifth switch tube ( S 5) Duty cycle, is the switching cycle of the switch tube; In mode 2, the first switch tube ( S 1) The second switch tube ( S 2) The fifth switch tube ( S 5) and the seventh switch tube ( S 7) Close, the third switch tube ( S 3) The fourth switch tube ( S 4) The sixth switch tube ( S 6) and the eighth switch tube ( S 8) Open, the duration of mode 2 is ; In mode 3, the third switch tube ( S 3) The fourth switch tube ( S 4) The sixth switch tube ( S 6) and the seventh switch tube ( S 7) Close, the first switch tube ( S 1) The second switch tube ( S 2) The fifth switch tube ( S 5) and the eighth switch tube ( S 8) Open; the duration of mode 3 is ; In mode 4, the first switch tube ( S 1) The second switch tube ( S 2), the sixth switch tube ( S 6) and the seventh switch tube ( S 7) Close, the third switch tube ( S 3) The fourth switch tube ( S 4) The fifth switch tube ( S 5) and the eighth switch tube ( S 8) Open; the duration of mode 4 is ; Is the first switch tube ( S 1) or the second switch tube ( S 2) Duty cycle.

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