Staggered flying capacitor multi-level converter

Abstract

The invention relates to an interlaced flying capacitor multi-level converter, which comprises a plurality of bridge arms and a phase shift pulse width modulation signal generating circuit, each bridge arm is provided with an upper arm and a lower arm which are coupled to the middle node, the upper arm is provided with a plurality of upper arm switches, the lower arm is provided with a plurality of lower arm switches, and the lower arm switches and the upper arm switches which are symmetrically coupled with the middle node as a switch pair. Capacitors are coupled between every two upper arm switches and every two lower arm switches. The phase shift pulse width modulation signal generating circuit is used for generating a plurality of switch control signals to control the conduction states of the upper arm switches and the lower arm switches.

Description

Technical Field

[0001] The present invention relates to a power converter, in particular to an interleaved flying capacitor multi-level converter. Background Art

[0002] In current power converters, an interleaved approach is often used to control the switches of multiple bridge arms and to coordinate with other circuit architectures to meet the needs of higher wattage applications. Figure 1 The power factor correction (PFC) architecture shown is a circuit diagram of a conventional interleaved boost PFC; or Figure 2 The structure shown is a circuit diagram of an interleaved totem-pole PFC.

[0003] In current interleaved power converters, in order to reduce the ripple of the input current, the PWM signals of the switches of the two bridge arms of the power converter are staggered by 180°. Figure 1 The signals PWM1 and PWM2 that control the switches Q1 and Q2 of the two bridge arms, respectively, are 180° out of phase with each other (for example, the start time of the high potential of PWM1 is set to 0°, the start time of the high potential of PWM2 is set to 180°, and the high potential times of PWM1 and PWM2 are substantially the same), or as Figure 2 The signals PWM3 and PWM4 that control the switches Q3 and Q4 of the two bridge arms are 180° out of phase with each other (for example, referring to the above description, PWM3 is 0° and PWM4 is 180°). This allows the current I flowing through the two inductors to be L_a and I L_b The peak and trough of the current are out of phase by 180°, thereby reducing the total input current I total (I total =I L_a +I L_b ) ripples.

[0004] With the recent increasing demand for high-power, high-efficiency products, many new architectures have emerged to overcome the limitations of existing architectures. Among them, the flying capacitor multi-level circuit can be applied to power factor correctors or other power converters.

[0005] like Figure 3 As shown, it is a schematic circuit diagram of a flying capacitor multi-stage circuit, wherein the upper arm has a switch S connected in series. 1a ,S 2a ...S na, whose lower arm has a switch S in series 1b ,S 2b ...S nb , and connect capacitors C1, C2...C between the nodes of the upper and lower arm switches. (n-1) , that is, in switch S 1a , switch S 2a The node and switch S 1b , switch S 2b Connect capacitor C1 between the nodes, and so on. The number of levels of the flying capacitor multi-level circuit is determined based on Figure 3 2×n switches S 1b ...S nb and switch S 1a ...S na In S 1b Follow S 1a The number of potentials that the connected intermediate node N can generate is determined by the number of potentials. In other words, if the intermediate node of the flying capacitor multi-level circuit can generate three potentials, the number of levels is 3; if it can generate five potentials, the number of levels is 5, and so on. Figure 3 The flying capacitor multi-stage circuit has n+1 stages. This circuit is suitable for higher-wattage applications, but considering factors such as the switch's current handling and temperature performance, an interleaved architecture can be used to distribute the energy.

[0006] When using phase-shift PWM (PSPWM) technology to control the switching of a multi-stage flying capacitor circuit, the phase difference between the switches in the same bridge arm is based on the formula Phase shift is performed, where Phase is the angle to be shifted and L is the number of levels of the flying capacitor multi-level circuit. Figure 4 The number of levels of the flying capacitor multi-level circuit is L = 3. According to the formula Phase = 180°, the switch S of bridge arm a 1A_a With switch S 1B_a The phase difference of the control signal of switch S is 180°. 2A_a With switch S 2B_a The phase difference of the control signal is 180°, and the switch S of the bridge arm b 1A_b With switch S 1B_b The phase difference of the control signal of switch S is 180°. 2A_b With switch S 2B_b The phase difference of the control signal is 180°. In the above-mentioned interleaved structure, in order to make the peak and valley of the current out of phase, the switch control signal of the switch of bridge arm a and the corresponding switch of bridge arm b will be out of phase by 180°. According to this concept, we can get Figure 5 The switch control signal control situation.

[0007] However, in the Figure 5 During the verification process of PSPWM control, it was found that Figure 5 the inductor current I within L_a and the inductor current I L_b do not have a 180° phase shift between the peaks and valleys as expected. Therefore, the total input current I after summation total also fails to achieve the goal of reducing the ripple.

[0008] Therefore, how to design a staggered flying capacitor multi-level converter to solve the problems and technical bottlenecks existing in the prior art has become an important research topic for the inventors of this case. Summary of the Invention

[0009] An object of the present invention is to provide a staggered flying capacitor multi-level converter for supplying power to a load according to a power source. The staggered flying capacitor multi-level converter includes a first bridge arm, a second bridge arm, and a phase-shifted pulse width modulation signal generation circuit. The first bridge arm includes a first flying capacitor multi-level circuit, which includes a first intermediate node for coupling to the power source, a first upper arm having n first upper arm switches, a first lower arm having n first lower arm switches, and (n - 1) capacitors respectively coupled to the first upper arm and the first lower arm. A first end of the first upper arm is used for coupling to the load, a second end of the first upper arm is coupled to the first intermediate node, a first end of the first lower arm is coupled to the first intermediate node, and a second end of the first upper arm is used for coupling to the load. The second bridge arm includes a second flying capacitor multi-level circuit, which includes a second intermediate node for coupling to the power source, a second upper arm having n second upper arm switches, a second lower arm having n second lower arm switches, and (n - 1) capacitors respectively coupled to the second upper arm and the second lower arm. A first end of the second upper arm is used for coupling to the load, a second end of the second upper arm is coupled to the second intermediate node, a first end of the second lower arm is coupled to the second intermediate node, and a second end of the second upper arm is used for coupling to the load. The phase-shifted pulse width modulation signal generation circuit is used to generate a plurality of pulse width modulated switch control signals to respectively control the on-off states of the plurality of upper arm switches and the plurality of lower arm switches; where n is a positive integer greater than 1. There is a 180-degree phase difference between the n first upper arm switch control signals generated by the phase-shifted pulse width modulation signal generation circuit for controlling the n first upper arm switches and the n first lower arm switch control signals for controlling the n first lower arm switches; there is a 180-degree phase difference between the n second upper arm switch control signals generated by the phase-shifted pulse width modulation signal generation circuit for controlling the n second upper arm switches and the n second lower arm switch control signals for controlling the n second lower arm switches; there is a phase difference of (h - 1) third phase angles θ3 between the h-th first upper arm switch and the first first upper arm switch, h is a positive integer and 1 < h <= n, and the third phase angle L is the number of stages of the first flying capacitor multi-stage circuit, and L=n+1; there is a phase difference of a first phase angle θ1 between the i-th second upper arm switch and the h-th first upper arm switch, i is a positive integer and 1≦i≦n, wherein the first phase angle θ1 is not equal to the second phase angle Where y = 1, 2,…(L-2).

[0010] An object of the present invention is to provide an interleaved flying capacitor multi-level converter, comprising a plurality of bridge arms and a phase-shifted pulse-width modulation signal generation circuit. Each bridge arm is a flying capacitor multi-level circuit, each having an upper arm and a lower arm coupled to an intermediate node, the upper arm having a plurality of upper arm switches, and the lower arm having a plurality of lower arm switches; a capacitor is coupled between every two upper arm switches and every two lower arm switches. The phase-shifted pulse-width modulation signal generation circuit generates a plurality of switch control signals to control the conduction states of the upper arm switches and the lower arm switches, respectively. wherein the plurality of first upper arm switch control signals of a first upper arm of a first bridge arm among the plurality of bridge arms differ from each other by a third phase angle θ3, and the plurality of first lower arm switch control signals of a first lower arm of the first bridge arm differ from the corresponding plurality of first upper arm switch control signals by 180 degrees; wherein the plurality of first upper arm switch control signals differ from the plurality of second upper arm switch control signals of a second upper arm of a second bridge arm among the plurality of bridge arms by a first phase angle θ1, and the plurality of second lower arm switch control signals of a second lower arm of the second bridge arm differ from the corresponding plurality of second upper arm switch control signals by 180 degrees; wherein the first phase angle θ1 is an optional phase angle One of them, m is the number of the multiple bridge arms, L is the number of stages of the flying capacitor multi-stage circuit, and x=1, 2, ... m×(L-1)-1.

[0011] Therefore, the interleaved flying capacitor multi-level converter proposed in the present invention has the following features and advantages: By using a phase-shifted pulse width modulation control signal with a specific phase angle for the multi-leg switches, the peaks and valleys of the input current in all or some of the legs are staggered, thereby achieving optimal ripple suppression for the total input current.

[0012] In order to further understand the techniques, means and effects adopted by the present invention to achieve the intended objectives, please refer to the following detailed description of the present invention and the accompanying drawings. It is believed that the objectives, features and characteristics of the present invention can be further understood in detail. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1The present invention is a circuit diagram of an existing interleaved boost power factor corrector;

[0014] Figure 2 The present invention is a circuit diagram of an existing interleaved totem pole power factor corrector;

[0015] Figure 3 A schematic circuit diagram of a conventional multi-stage flying capacitor circuit;

[0016] Figure 4 A circuit diagram of a conventional interleaved flying capacitor multi-level totem pole power factor corrector;

[0017] Figure 5 A circuit diagram of a conventional interleaved flying capacitor multi-level totem pole power factor corrector;

[0018] Figure 6 A circuit diagram of an embodiment of an interleaved flying capacitor multi-level converter according to the present invention;

[0019] Figure 7 A circuit diagram of another embodiment of an interleaved flying capacitor multi-level converter according to the present invention;

[0020] Figure 8 Schematic diagram of input current waveform of the interleaved flying capacitor multi-level converter of the present invention in a two-bridge-arm, four-level flying capacitor architecture;

[0021] Figure 9 Schematic diagram of input current waveform of the interleaved flying capacitor multi-level converter of the present invention under a three-bridge-arm, three-level flying capacitor architecture;

[0022] Figures 10 to 12 1 and 2 are schematic diagrams of input current waveform and control signal waveform of the interleaved flying capacitor multi-level converter of the present invention under a two-bridge-arm, three-level flying capacitor architecture.

[0023] Explanation of Figure Numbers

[0024] 600,700: Interleaved flying capacitor multi-level converter

[0025] 610: Phase-shifted pulse width modulation signal generating circuit

[0026] S 1A_1 ~S nA_1 ,…S 1A_m ~S nA_m :Upper arm switch

[0027] S 1B_1 ~S nB_1 ,…S 1B_m ~S nB_m :Lower arm switch

[0028] V 1A_1 ~VnA_1 ,…V 1A_m ~V nA_m : Upper arm switch control signal

[0029] V 1B_1 ~V nB_1 ,…V 1B_m ~V nB_m :Lower arm switch control signal

[0030] C 1_1 ~C (n-1)_1 ,…C 1_m ~C (n-1)_m :Flying Capacitor

[0031] N1~N m :Intermediate Node

[0032] L1…L m :inductance

[0033] Vin: power supply

[0034] Vo: output voltage

[0035] Co: output capacitance

[0036] Load:

[0037] D1, D2: diodes

[0038] RECT: Rectifier circuit

[0039] I L_1 …I L_m :Input current

[0040] I total :Total input current

[0041] Δphase: optional phase angle

[0042] θ1: first phase angle

[0043] ΔphaseX: second phase angle

[0044] θ3: third phase angle DETAILED DESCRIPTION

[0045] The technical content and detailed description of the present invention are now described as follows with reference to the accompanying drawings.

[0046] See Figure 6FIG. 1 is a circuit diagram of an interleaved flying capacitor multi-level converter 600 of the present invention. The interleaved flying capacitor multi-level converter 600 is used to supply power to a load Load based on an AC input power source Vin. In this embodiment, the interleaved flying capacitor multi-level converter 600 can be combined with a power factor control technology to have a power factor correction function, which can adjust the input current to improve the power factor. Figure 6 The interleaved flying capacitor multi-level converter 600 is described with a totem pole circuit structure as an embodiment, but the present invention can also be used with a boost circuit (such as Figure 7 The interleaved flying capacitor multi-level converter 700 shown in the figure can be used to provide functions such as circuit conversion or power factor correction.

[0047] by Figure 6 As shown in the embodiment, the interleaved flying capacitor multi-level converter 600 includes m bridge arms, where m is a positive integer greater than 2. Each of the bridge arms 1-m has a plurality of terminals coupled to the intermediate nodes N1-N m An upper arm and a lower arm. Taking bridge arm 1 as an example, its upper arm has n (n is a positive integer greater than 1) upper arm switches S 1A_1 ~S nA_1 , and its lower arm has n lower arm switches S 1B_1 ~S nB_1 Similarly, taking bridge arm m as an example, its upper arm has n upper arm switches S 1A_m ~S nA_m , and its lower arm has n lower arm switches S 1B_m ~S nB_m .

[0048] Furthermore, the intermediate nodes N1 to N m The lower arm switch S is symmetrically coupled 1B_1 ~S nB_1 ,…S 1B_m ~S nB_m Respectively with the upper arm switch S 1A_1 ~S nA_1 ,…S 1A_m ~S nA_m Form a switch pair. Taking bridge arm 1 as an example, the upper arm switch S 1A_1 With lower arm switch S 1B_1 Form a switch pair, upper arm switch S nA_1 With lower arm switch S nB_1 Form a switch pair. Similarly, the middle-coupled upper arm switch and the symmetrically coupled lower arm switch also form a switch pair. Taking bridge arm m as an example, the upper arm switch S 1A_m With lower arm switch S 1B_m Form a switch pair, upper arm switch S nA_m With lower arm switch S nB_mA switch pair is formed. Similarly, the centrally coupled upper arm switch and the symmetrically coupled lower arm switches also form a switch pair.

[0049] Furthermore, each of the bridge arms 1…m further comprises a plurality of capacitors C 1_1 ~C (n-1)_1 ,…C 1_m ~C (n-1)_m , the two ends of each capacitor are respectively coupled to the two ends of each switch pair, that is, the two upper arm switches S 1A_1 ~S nA_1 ,…S 1A_m ~S nA_m With two lower arm switches S 1B_1 ~S nB_1 ,…S 1B_m ~S nB_m Capacitors C are coupled between 1_1 ~C (n-1)_1 ,…C 1_m ~C (n-1)_m Taking bridge arm 1 as an example, capacitor C 1_1 The first end is coupled to the upper arm switch S 1A_1 With upper arm switch S 2A_1 (not shown) the common point, capacitor C 1_1 The second end is coupled to the lower arm switch S 1B_1 With lower arm switch S 2B_1 (not shown in the figure). Capacitor C (n-1)_1 The first end is coupled to the upper arm switch S nA_1 With upper arm switch S (n-1)A_1 (not shown) the common point, capacitor C (n-1)_1 The second end is coupled to the lower arm switch S nB_1 With lower arm switch S (n-1)B_1 Similarly, capacitors are also coupled between the two upper-arm switches and the two lower-arm switches coupled in the middle.

[0050] Therefore, each bridge arm 1 ... m of the interleaved flying capacitor multi-level converter 600 is a flying capacitor multi-level circuit. Each bridge arm 1 ... m includes n switches in its upper and lower arms, respectively, and (n-1) capacitors are coupled between the upper and lower arms, with the number of levels L = n+1.

[0051] In this embodiment, the interleaved flying capacitor multi-level converter 600 includes a plurality of inductors L1 . . . L m , inductor L1…L m The first end of the inductor L1 is coupled to the first end of the power supply Vin, and the inductor L1...L m The second end of each bridge arm 1...m is respectively coupled to the middle node N1...N m Inductor L1…L m The input current is IL_1 …I L_m , I L_1 …I L_m The total input current I total The power supply Vin and each bridge arm 1…m are coupled to a rectifier circuit RECT, an output capacitor Co, and a load Load to provide an output voltage Vo to power the load Load. In this embodiment, the rectifier circuit RECT includes two diodes D1 and D2. The first end of each bridge arm 1…m is coupled to the first end of diode D1, the second end of diode D1 is coupled to the first end of diode D2, the second end of each bridge arm 1…m is coupled to the second end of diode D2, and the second end of the power supply Vin is coupled to the second end of diode D1 and the first end of diode D2.

[0052] In addition, the interleaved flying capacitor multi-level converter 600 includes a phase shift pulse width modulation (PMM) signal generating circuit 610. The PMPM signal generating circuit 610 can be implemented using a digital circuit, an analog circuit, a signal processor, a microcontroller, or other suitable implementations to generate a plurality of upper arm switch control signals V 1A_1 ~V nA_1 ,…V 1A_m ~V nA_m and the lower arm switch control signal V 1B_1 ~V nB_1 ,…V 1B_m ~V nB_m , respectively used to control each upper arm switch S of each bridge arm 1A_1 ~S nA_1 ,…S 1A_m ~S nA_m and each lower arm switch S 1B_1 ~S nB_1 ,…S 1B_m ~S nB_m These switch control signals are implemented by phase-shift pulse width modulation. Taking bridge arm 1 as an example, the upper arm switch control signal V 1A_1 ~V nA_1 is a phase-shifted pulse width modulation signal, and the lower arm switch control signal V 1B_1 ~V nB_1 Then they are the upper arm switch control signal V 1A_1 ~V nA_1 Furthermore, the switching control signal corresponding to each bridge arm 2…m (or part of the bridge arm) can also be set as a phase-shifted PWM signal relative to the switching control signal corresponding to bridge arm 1, so as to achieve an interleaved control implementation.

[0053] In this embodiment, the phase-shifted pulse width modulation signal generating circuit 610 generates the upper arm switch control signal V 1A_1 ~V nA_1 They are essentially the same pulse width modulation signals, but adjacent switch control signals have a phase difference of the third phase angle θ3. The third phase angle θ3 can be set to θ3 = (360°) / (L-1), where L is the number of stages of the flying capacitor multi-stage circuit. According to the above formula, the number of stages L = (n+1), where n is the number of switches in the upper arm of the bridge arm or the number of switches in the lower arm of the bridge arm, the third phase angle θ3 can also be set to θ3 = (360°) / n. For example, the upper arm switch control signal V 2A_1 ,V 2A_1 …V nA_1 Respectively with the upper arm switch control signal V1 A_1 The PWM signals have a phase difference of 1…(n-1) third phase angle θ3, and the switch S of the bridge arm 1 1A_1 The control signal V 1A_1 The pulse width modulation signal has a duty cycle of 10%, and the switch S2 of the bridge arm 1 is A_1 The control signal V 2A_1 V 1A_1 The pulse width modulation signal V with a phase shift of θ3 2A_1 =V 1A_1 ×e jθ3 , and the switch S of bridge arm 1 nA_1 The control signal V nA_1 V 1A_1 The pulse width modulation signal V is shifted by (n-1)×θ3 nA_1 =V 1A_1 ×e j(n-1)θ3 . Lower arm switch control signal V 1B_1 ~V nB_1 ,…V 1B_m ~V nB_m Then they are the upper arm switch control signal V 1A_1 ~V nA_1 ,…V 1A_m ~V nA_m A pulse width modulated signal with a phase shift of 180 degrees. For example: V 1B_1 =V 1A_1 ×e jπ , V 2B_1 =V 2A_1 ×e jπ =V 1A_1 ×e j(π+θ3) …, V nB_1 =V nA_1 ×e jπ =V 1A_1 ×e j(π+(n-1)θ3) .

[0054] In addition, the phase-shifted PWM signal generating circuit 610 can be configured to generate a phase difference of 1, 2, ... (m-1) first phase angle θ1 between the switch control signals of bridge arms 2, 3, ... m and the switch control signal corresponding to bridge arm 1. For example, V 1A_m =V 1A_1 ×e j(m-1)θ1 , V 2A_m =V 2A_1 ×e j(m-1)θ1 …, V nA_m =V nA_1 ×e j(m-1)θ1 And V 1B_m =V 1B_1 ×e j(m-1)θ1 , V 2B_m =V 2B_1 ×e j(m-1)θ1 …, V nB_m =V nB_1 ×e j(m-1)θ1 The first phase angle θ1 can be selected from one of the following formulas: Where m is the number of bridge arms; L is the number of stages of the flying capacitor multi-stage circuit; and x = 1, 2, ...m × (L-1)-1. Assuming that the number of bridge arms of the interleaved flying capacitor multi-stage converter 600 is m = 2 and the number of stages of the flying capacitor multi-stage circuit in each bridge arm is L = 4, the above formula can be applied to select one of 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees as the first phase angle θ1. For example, if the first phase angle θ1 is set to 60 degrees, the corresponding switch control signal of bridge arm 2 is equal to the switch control signal of bridge arm 1, delayed by 60 degrees (in another embodiment, it can also be set to 60 degrees ahead). If the first phase angle θ1 is set to 120 degrees, the corresponding switch control signal of bridge arm 2 is equal to the switch control signal of bridge arm 1, delayed by 120 degrees (in another embodiment, it can also be set to 120 degrees ahead), and so on.

[0055] In another embodiment, the interleaved control of the present invention can be further adjusted to reduce the total input current I total Therefore, after calculating Δphase, the second phase angle ΔphaseX can be excluded from selection, that is, the selected first phase angle θ1 does not include the second phase angle ΔphaseX. The second phase angle ΔphaseX is: Where L is the number of stages of the flying capacitor multi-stage circuit; y = 1...(L-2). Assuming that the number of stages of the flying capacitor multi-stage circuit of each bridge arm of the interleaved flying capacitor multi-stage converter 600 is L = 4, the second phase angle ΔphaseX = 120 degrees and 240 degrees. Therefore, when the first phase angle θ1 can select one of Δphase = 60 degrees, 120 degrees, 180 degrees, 240 degrees and 300 degrees, the second phase angle ΔphaseX = 120 degrees and 240 degrees is excluded. Therefore, the optional phase angle Δphase of the first phase angle θ1 is any one of the three phase angles of 60 degrees, 180 degrees and 300 degrees, so as to reduce the total input current I of the interleaved flying capacitor multi-stage circuit 600. total ripples.

[0056] Based on the aforementioned formula, Table 1 lists several optional phase angle Δphase and second phase angle ΔphaseX values ​​for a flying capacitor multi-level converter under different conditions of the number of bridge arms m and the number of levels L of the flying capacitor multi-level circuit.

[0057] Table 1

[0058]

[0059] Below, through Figures 8 to 10 The current waveform diagram illustrates the ripple reduction effect achieved by the interleaved flying capacitor multi-level converter 600 of the present invention. Figure 8 As shown, it is a schematic diagram of the input current waveform of the interleaved flying capacitor multi-level converter 600 under the two-bridge arm and four-level flying capacitor architecture. Figure 8 It can be clearly seen from the upper half of the figure that when the first phase angle θ1 is one of the optional phase angles Δphase = 60 degrees, 180 degrees or 300 degrees, the two input currents I L_1 with I L_2 The peaks and troughs of the wave pattern are staggered to achieve the effect of phase shift. Figure 8 The input current I L_1 with I L_2 For sawtooth wave, when the input current I L_1 When the input current I L_2 Close to the minimum value; and when the input current I L_2 When the input current I L_1 is close to the minimum value. Therefore, the input current I L_1 and input current I L_2 The peaks and valleys of the wave achieve the effect of phase shift, so that the total input current I total To achieve the best ripple suppression effect (see Figure 10 Total input current I total ). However, in Figure 8It can be clearly seen from the lower half that when the first phase angle θ1 is equal to the second phase angle ΔphaseX = 120 degrees or 240 degrees, due to the two input currents I L_1 with I L_2 The peaks and troughs of the input current are not significantly out of phase, so the total input current I total The ripple suppression effect is poor.

[0060] Likewise, if Figure 9 As shown, it is a schematic diagram of the input current waveform of the interleaved flying capacitor multi-level converter 600 under the three-bridge arm and three-level flying capacitor architecture. Figure 9 It can be clearly seen from the upper half of the figure that when the first phase angle θ1 is one of the optional phase angles Δphase = 60 degrees, 120 degrees, 240 degrees or 300 degrees, the input currents I L_1 , I L_2 and I L_3 The peaks and valleys of the input current can achieve the effect of phase shift, so the total input current I total To achieve the best ripple suppression effect. However, Figure 9 It can be clearly seen from the lower half that when the first phase angle θ1 is equal to the second phase angle ΔphaseX = 180 degrees, due to the three input currents I L_1 , I L_2 and I L_3 The peaks and troughs of the input current are not significantly out of phase, so the total input current I total The ripple suppression effect is poor.

[0061] In addition, see Figures 10 to 12 , which are schematic diagrams of input current waveforms and control signal waveforms of the interleaved flying capacitor multi-level converter 600 with two bridge arms and three-level flying capacitor architecture, with different first phase angles θ1. Figure 10 The first phase angle θ1 is 90 degrees, Figure 11 The first phase angle θ1 is 180 degrees and Figure 12 The first phase angle θ1 is 270 degrees. As mentioned above, referring to Table 1, in the two-arm (m=2) and three-level flying capacitor (L=3) architecture, the first phase angle θ1 can be selected from 90 degrees, 180 degrees, and 270 degrees, and the second phase angle ΔphaseX (i.e., 180 degrees) is excluded. Therefore, the preferred solution is that the first phase angle θ1 can be selected as Δphase = 90 degrees or 270 degrees. In other words, Figure 10 The first phase angle θ1 shown is 90 degrees or Figure 12 The first phase angle θ1 shown is 270 degrees, which can make the two input currents I L_1 with I L_2 The peaks and troughs of the wave achieve the effect of mismatching, so Figure 10 and Figure 12For example, when the input current I L_1 with I L_2 When the peak-to-peak value is 7 amperes, the total input current I total The ripple can be suppressed to about 2 amps (peak to peak). Figure 11 The first phase angle θ1 shown is 180 degrees, which cannot make the two input currents I L_1 with I L_2 The peaks and valleys of the input current have obvious phase mismatch effects. L_1 with I L_2 When the peak-to-peak value is 7 amperes, the total input current I total The ripple is about 14 amps, obviously Figure 11 The total input current I total The ripple suppression effect is better in Figure 10 The first phase angle θ1 is selected as 90 degrees or Figure 12 The first phase angle θ1 is selected as 270 degrees, which is poor.

[0062] See also Figure 10 and Figure 4 ,like Figure 10 As shown, the lower arm switch S of the control bridge arm 1 is controlled 1B_1 The control signal is V 1B_1 , and control the lower arm switch S of bridge arm 1 2B_1 The control signal is V 2B_1 The phase angle difference between the two is the third phase angle θ3 = 180 degrees, and the control and bridge arm 1 lower arm switch S 1B_1 The lower arm switch S of the bridge arm 2 at the corresponding position 1B_2 The control signal is V 1B_2 , the phase angle difference between the two is the first phase angle θ1 = 90 degrees. Figure 10 In the embodiment, when the first phase angle θ1 is selected to be 90 degrees, the two input currents I L_1 with I L_2 The peaks and valleys of the input current can achieve the effect of phase shift, so the total input current I total Produces better ripple suppression effect.

[0063] Similarly, see Figure 12 and Figure 4 , control the lower arm switch S of bridge arm 1 1B_1 The control signal is V 1B_1 , and control the lower arm switch S of bridge arm 1 2B_1 The control signal is V 2B_1 The phase angle difference between the two is the third phase angle θ3 = 180 degrees, and the control and bridge arm 1 lower arm switch S 1B_1 The lower arm switch S of the bridge arm 2 at the corresponding position 1B_2 The control signal is V 1B_2, the phase angle difference between the two is the first phase angle θ1 = 270 degrees. Figure 12 In the embodiment, when the first phase angle θ1 is selected to be 270 degrees, the two input currents I L_1 with I L_2 The peaks and valleys of the input current can achieve the effect of phase shift, so the total input current I total Produces better ripple suppression effect.

[0064] However, see Figure 11 and Figure 4 , control the lower arm switch S of bridge arm 1 1B_1 The control signal is V 1B_1 , and control the lower arm switch S of bridge arm 1 2B_1 The control signal is V 2B_1 The phase angle difference between the two is the third phase angle θ3 = 180 degrees, and the control and bridge arm 1 lower arm switch S 1B_1 The lower arm switch S of the bridge arm 2 at the corresponding position 1B_2 The control signal is V 1B_2 , the phase angle difference between the two is the first phase angle θ1 = 180 degrees. Figure 11 In the embodiment, when the first phase angle θ1 is selected to be 180 degrees, it is impossible to make the two input currents I L_1 with I L_2 The peaks and valleys of the input current have obvious phase mismatch effects, so the total input current I total Produces better ripple suppression effect.

[0065] In some embodiments, the phase difference of the switch control signals generated by the phase-shifted pulse width modulation signal generating circuit 610 between each bridge arm can be set to use the same first phase angle. For example, each switch control signal of bridge arm 2 is the corresponding switch control signal of bridge arm 1 delayed by a first phase angle θ1, each switch control signal of bridge arm 3 is the corresponding switch control signal of bridge arm 1 delayed by 2×Δphase, and each switch control signal of bridge arm m is the corresponding switch control signal of bridge arm 1 delayed by (m-1)×Δphase. Therefore, the input current I L_1 …I L_m The peaks and valleys of the input current have obvious phase shift effects, which can affect the total input current I total Produces a ripple suppression effect.

[0066] In some other embodiments, due to different design considerations such as simplified control, the phase-shifted pulse-width modulation signal generation circuit 610 may be configured to generate the switching control signals of some of the bridge arms with the same first phase angle, and the phase delays of the switching control signals of some of the bridge arms do not adopt this method. For example, the switching control signals of bridge arms 2 to g are the switching control signals of the corresponding bridge arm 1 delayed by 1 to (g - 1) first phase angles θ1, but the switching control signals of bridge arms (g + 1) to m are not the switching control signals of the corresponding bridge arm 1 delayed by g to (m - 1) Δphase, where g is a positive integer and 2 < g < m. Since there are obvious phase shift effects in the peaks and valleys of the input currents I L_1 …I L_g of bridge arms 1 to g, even if there are no obvious phase shift effects in the peaks and valleys of the input currents I L_1 …I L_g of bridge arms (g + 1) to m, the total input current I total obtained by summation can still produce an acceptable ripple suppression effect.

[0067] In some other embodiments, the phase difference between the switching control signals generated by the phase-shifted pulse-width modulation signal generation circuit 610 for each bridge arm (or some of the bridge arms) can also be set to be not equal to the first phase angle, and only an appropriate angle other than the second phase angle ΔphaseX needs to be selected to make the peaks and valleys of the input currents I L_1 …I L_m of all or some of the bridge arms have phase shift effects, so that the total input current I total can produce an acceptable ripple suppression effect.

[0068] In summary, the present invention has the following features and advantages: By using an interleaved flying-capacitor multi-level converter and applying phase-shifted pulse-width modulation control signals with specific phase angles to the switches of multiple bridge arms, the peaks and valleys of the input currents of all or some of the bridge arms achieve phase shift effects, thereby achieving a ripple suppression effect on the total input current.

[0069] The above description is only a detailed description and the accompanying drawings of the preferred specific embodiments of the present invention. However, the features of the present invention are not limited thereto, and are not intended to limit the present invention. The scope of the present invention should be based on the following claims. All embodiments that conform to the spirit of the scope of the claims of the present invention and its similar variations should be included in the scope of the present invention. Any changes or modifications that can be easily conceived by any person skilled in the art within the field of the present invention can be covered by the patent scope of the present case below.

Claims

1. An interleaved flying capacitor multi-level converter for supplying power to a load based on a power source, comprising: The first bridge arm includes a first flying capacitor multi-stage circuit, which includes a first intermediate node for coupling to the power source, a first upper arm having n first upper arm switches, a first lower arm having n first lower arm switches, and (n-1) capacitors coupled to the first upper arm and the first lower arm respectively, a first end of the first upper arm for coupling to the load, a second end of the first upper arm for coupling to the first intermediate node, a first end of the first lower arm for coupling to the first intermediate node, and a second end of the first upper arm for coupling to the load; The second bridge arm includes a second flying capacitor multi-stage circuit, which includes a second intermediate node for coupling to the power source, a second upper arm having n second upper arm switches, a second lower arm having n second lower arm switches, and (n-1) capacitors coupled to the second upper arm and the second lower arm, respectively, a first end of the second upper arm for coupling to the load, a second end of the second upper arm for coupling to the second intermediate node, a first end of the second lower arm for coupling to the second intermediate node, and a second end of the second upper arm for coupling to the load; as well as A phase-shifted pulse width modulation signal generating circuit for generating a plurality of pulse width modulated switch control signals to respectively control the conduction states of the plurality of upper arm switches and the plurality of lower arm switches; Where n is a positive integer greater than 1; The n first upper arm switch control signals generated by the phase-shifted pulse width modulation signal generating circuit for controlling the n first upper arm switches and the n first lower arm switch control signals for controlling the n first lower arm switches each have a phase difference of 180 degrees; The n second upper arm switch control signals generated by the phase-shifted pulse width modulation signal generating circuit for controlling the n second upper arm switches and the n second lower arm switch control signals for controlling the n second lower arm switches respectively have a phase difference of 180 degrees; There is a phase difference of (h - 1) third-phase angles θ3 between the h-th first upper-arm switch and the 1st first upper-arm switch, where h is a positive integer and 1 < h <= n, and the third-phase angle L is the number of levels of the first flying-capacitor multi-level circuit, and L = n + 1; There is a phase difference of a first phase angle θ1 between the i-th second upper arm switch and the h-th first upper arm switch, i is a positive integer and 1≦i≦n, wherein the first phase angle θ1 is not equal to the second phase angle Where y = 1, 2,…(L-2).

2. The interleaved flying capacitor multi-level converter according to claim 1, wherein the first phase angle θ1 is a selectable phase angle One of them, x=1,2,…2×(L-1)-1.

3. The interleaved flying capacitor multi-level converter according to claim 1 , further comprising (m−2) bridge arms, where m is a positive integer greater than 2, wherein the g-th bridge arm comprises a g-th flying capacitor multi-level circuit, comprising a g-th intermediate node for coupling to the power source, a g-th upper arm having n g-th upper arm switches, a g-th lower arm having n g-th lower arm switches, and (n−1) capacitors coupled to the g-th upper arm and the g-th lower arm, respectively, wherein a first end of the g-th upper arm is coupled to the load, a second end of the g-th upper arm is coupled to the first intermediate node, a first end of the g-th lower arm is coupled to the g-th intermediate node, and a second end of the g-th upper arm is coupled to the load; g is a positive integer and 2 <g<=m; The n g th upper arm switch control signals generated by the phase-shifted pulse width modulation signal generating circuit for controlling the n g th upper arm switches and the n g th lower arm switch control signals for controlling the n g th lower arm switches respectively have a phase difference of 180 degrees; There is a phase difference of (i-1) first phase angles θ1 between the i-th g-th upper arm switch and the i-th first upper arm switch, where i is a positive integer and 1≦i≦n, wherein the first phase angle θ1 is not equal to the second phase angle Where y = 1, 2,…(L-2).

4. The interleaved flying capacitor multi-level converter according to claim 3, wherein the first phase angle θ1 from the second bridge arm to the g-th bridge arm is a selectable phase angle One of them, and the first phase angle θ1 from the g+1th bridge arm to the mth bridge arm is not an optional phase angle One of them, 2 <g≦m,x=1,2,…m×(L-1)-1。 5. The interleaved flying capacitor multi-level converter according to claim 3, wherein the first phase angle θ1 from the second bridge arm to the mth bridge arm is a selectable phase angle One of them, x=1,2,…m×(L-1)-1.

6. An interleaved flying capacitor multi-level converter comprising: A plurality of bridge arms, each of the bridge arms being a flying capacitor multi-stage circuit, each of the bridge arms having an upper arm and a lower arm coupled to an intermediate node, the upper arm having a plurality of upper arm switches, and the lower arm having a plurality of lower arm switches; Wherein, capacitors are coupled between the two upper arm switches and the two lower arm switches; as well as A phase-shifted pulse width modulation signal generating circuit for generating a plurality of switch control signals to respectively control the conduction states of the plurality of upper arm switches and the plurality of lower arm switches; wherein the plurality of first upper arm switch control signals of the first upper arm of the first bridge arm among the plurality of bridge arms differ from each other by a third phase angle θ3, and the plurality of first lower arm switch control signals of the first lower arm of the first bridge arm differ from the corresponding plurality of first upper arm switch control signals by 180 degrees; wherein the plurality of first upper arm switch control signals differ from the plurality of second upper arm switch control signals of a second upper arm of a second bridge arm among the plurality of bridge arms by a first phase angle θ1, and the plurality of second lower arm switch control signals of a second lower arm of the second bridge arm differ from the corresponding plurality of second upper arm switch control signals by 180 degrees; The first phase angle θ1 is an optional phase angle One of them, m is the number of the multiple bridge arms, L is the number of layers of the flying capacitor multi-layer circuit, and x=1, 2, ...m×(L-1)-1.

7. The interleaved flying capacitor multi-level converter according to claim 6, wherein the first phase angle does not include one or more second phase angles; wherein the one or more second phase angles are: Where y = 1, 2,…(L-2).

8. The interleaved flying capacitor multi-level converter according to claim 6, wherein the third

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