Optimized multi-resonant switched-tank converter based on partial power regulation

Abstract

The application discloses an optimized multi-resonant switching tank converter based on partial power regulation, which is composed of an optimized multi-resonant switching tank circuit (OMRSTC) and a four-switch Buck-Boost circuit (FSBB) in series at an input side and in parallel at an output side. In the converter, the OMRSTC works in an open loop mode and transmits most of the energy, and the FSBB works in a closed loop control mode, so that the output voltage can be conveniently adjusted to adapt to a wide range of input voltages. In the application, the inductance elements with the same working state are shared, so that the OMRSTC can solve the problem caused by the parameter error of passive elements only with one resonant inductance and one second resonant cavity, the number of resonant inductances does not increase with the increase of the OMRSTC conversion ratio, the circuit cost is greatly reduced, and the efficiency of the converter is further improved.

Description

Technical Field

[0001] This invention relates to the field of DC-DC converters, and more specifically to an optimized multi-resonant switching slot converter based on partial power regulation. Background Technology

[0002] With technological advancements, two-stage intermediate bus power supply architectures, consisting of intermediate bus converters and point-of-load converters, have become widely used in data centers. The intermediate bus converter typically employs a high-efficiency, high-power-density resonant switched-capacitor converter. However, resonant switched-capacitor converters face several challenges in large-scale applications: First, their voltage gain is structurally limited, resulting in a fixed turns ratio and unadjustable output voltage. Second, in large-scale production applications, variations in passive component parameters, particularly capacitor tolerances, lead to significant conduction losses and reduced converter efficiency. Finally, as the turns ratio of the resonant switched-capacitor converter increases, the number of resonant inductors in the circuit multiplies. Given the relatively large size of resonant inductors, this increase in number leads to a decrease in power density and an increase in cost.

[0003] Chinese invention patent (CN202210328005.1) discloses a buck converter based on a multi-resonant switching slot circuit and a Buck-Boost circuit. It addresses the inability of resonant switched-capacitor converters to adjust voltage by employing a quasi-parallel architecture, while utilizing a second resonant cavity to mitigate the impact of capacitor tolerance. However, this converter contains a relatively large number of resonant inductors and second resonant cavities, resulting in high cost, and its power density decreases significantly with increasing voltage transformation ratio. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned deficiencies in the prior art and provide an optimized multi-resonant switching slot converter based on partial power regulation. This converter retains the disturbance rejection performance of multi-resonant switching slot converters against differences in passive component parameters and also enables closed-loop control of the output voltage. Furthermore, the circuit requires only one resonant inductor and one second resonant cavity, and the number of resonant inductors does not increase with the increase of the converter's voltage ratio.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] An optimized multi-resonant switching slot converter based on partial power regulation is constructed by connecting an optimized multi-resonant switching slot circuit (OMRSTC) and a four-switch Buck-Boost circuit (FSBB) with its input in series and output in parallel.

[0007] OMRSTC, containing 4 wing-side switching transistors Q 1a Q1b Q 2a Q 2b 4 rectifier-side switching transistors Q 3a Q 3b Q 4a Q 4b Two resonant capacitors C r1 and C r2 1 resonant inductor L r One bypass capacitor C2 and one clamping capacitor C F ;

[0008] FSBB contains four switching transistors Q1, Q2, Q3, and Q4, and capacitor C. b With inductor L b ;

[0009] Q 1a The current input terminal is electrically connected to the positive terminal of the voltage source; Q 1a Q 1b Q 2a Q 2b The current output terminal and current input terminal are electrically connected in sequence; Q 3a The current output terminal and Q 3b Electrical connection of current input terminal, Q 3b The current output terminal is electrically connected to the negative terminal of the voltage source; Q 4b The current output terminal and Q 4a Electrical connection of current input terminal, Q 4a The current output terminal is electrically connected to the negative terminal of the voltage source;

[0010] C r1 One end and Q 1a Electrical connection of the current output terminal; C F One end and Q 1b Electrical connection of the current output terminal; C F The other end and Q 4a Electrical connection of the current input terminal; C r2 One end and Q 2a Electrical connection of the current output terminal; L r One end and C r1 and C r2 Electrical connection of current output terminal, L r The other end and Q 3b Electrically connected to the current input terminal; one end of C2 is connected to C r1 and C r2 The current output terminal of C2 is electrically connected; the other end of C2 is connected to Q. 3b Electrical connection of the current input terminal;

[0011] C b One end and Q2b Electrical connection of the current output terminal; C b The other end is electrically connected to the negative terminal of the voltage source; inductor L b One end of the inductor is electrically connected to the current output terminal of Q1; b The other end is electrically connected to the current input terminal of Q3; the current input terminal of Q1 is connected to Q... 2b The current output terminal of Q1 is electrically connected to the current input terminal of Q2; the current output terminal of Q2 is electrically connected to the negative terminal of the voltage source; the current output terminal of Q3 is electrically connected to the negative terminal of the voltage source; the current input terminal of Q3 is electrically connected to the current output terminal of Q4.

[0012] Q 3a Q 4b The current input terminal of Q1 serves as the output terminal of the (1) optimized multi-resonant switch slot circuit (OMRSTC); the current input terminal of Q4 serves as the output terminal of the (2) four-switch buck-boost circuit (FSBB); Q 3a Q 4b It is electrically connected to the current input terminal of Q4 to supply power to the load.

[0013] In OMRSTC, the following constraints must be satisfied during parameter design: C r1 and C r2 Equal capacitance values; C2 << C r1 =C r2 <<C F Note C r1 C r2 With L r The common resonance frequency is f r C2 and L r The second resonant cavity frequency of the operation is f r2 ,

[0014]

[0015]

[0016] Q 1a Q 2a Q 3a Q 4a For the same driving signal, Q 1b Q 2b Q 3b Q 4b For the same driving signal, Q 1a and Q 1b Complementary conduction, with a certain dead time t. d The switching frequency is f sThe OMRSTC circuit operates in open-loop mode, uses fixed-frequency control, and satisfies the following constraints: f s >f r and

[0017] In FSBB, Q1 and Q2 are complementary conductors with a duty cycle of d1, and Q3 and Q4 are complementary conductors with a duty cycle of d. 2； FSBB employs a single-voltage loop control with input voltage feedforward. In the voltage regulator, the difference signal generated by comparing the output voltage sample value with the voltage reference value is superimposed with the sampled input voltage signal to generate four PWM signals, which are then supplied to Q. 1a Q 2a Q 3a Q 4a By controlling the duty cycles d1 and d2, the dynamic response of the output voltage to the input voltage is achieved.

[0018] The present invention has the following advantages and effects compared with the prior art:

[0019] (1) By sharing inductors that operate in the same state, the circuit contains only one resonant inductor, and the number of resonant inductors does not increase with the increase of the converter ratio. This can reduce the size of the converter, increase the power density of the circuit, and further reduce the application cost.

[0020] (2) A bypass capacitor much smaller than the resonant capacitor is connected in parallel across the resonant inductor, introducing a second resonant cavity with a frequency much higher than the resonant frequency. This weakens the adverse effects of capacitor tolerance on the circuit, and the circuit requires only one second resonant cavity loop, the number of which does not increase with the increase of the converter's turns ratio. Let the dead time be equal to the second resonant frequency f. r2 During half of the resonant cycle, the resonant slot current is reversed in a lossless manner, reducing the power loss of the converter.

[0021] (3) By using OMRSTC and FSBB input series and output parallel, a quasi-parallel architecture intermediate bus converter is constructed, which enables the converter to have voltage regulation capability and achieve higher efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a circuit diagram of the optimized multi-resonant switching slot converter based on partial power regulation proposed in this invention.

[0024] Figure 2 It is a traditional 4:1 switching resonant slot converter;

[0025] Figure 3 This is a circuit diagram of the 4:1 optimized multi-resonant switching slot converter disclosed in the embodiments of the present invention;

[0026] Figure 4 (a) Figure 4 (b) Figure 4 (c) and Figure 4 (d) is a schematic diagram of the current flow direction in the four working modes of 4∶1OMRSTC in the embodiment of the present invention;

[0027] Figure 5 This is a waveform diagram of the 4:1 OMRSTC circuit in one switching cycle in an embodiment of the present invention;

[0028] Figure 6 This is a closed-loop control block diagram of FSBB in an embodiment of the present invention;

[0029] Figure 7 It is a traditional 4:1 switching resonant slot converter capacitor C r1 C r2 Simultaneously changing ±20% of the resonant tank current (i) tank Waveform comparison;

[0030] Figure 8 The 4:10 MMRST C capacitor in this embodiment of the invention. r1 C r2 Simultaneously changing ±20% of the resonant tank current (i) tank Comparison of waveforms. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed description is illustrative and intended to further illustrate the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] The described embodiments are some, but not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are all within the scope of protection of the present invention.

[0034] The purpose of this invention is to provide an optimized multi-resonant switching slot converter based on partial power regulation, such as... Figure 1 As shown, it includes a 4:1 optimized multi-resonant switching slot circuit (OMRSTC) and a four-switch buck-boost circuit (FSBB). The OMRSTC operates in open-loop mode with a rated input voltage of 48V and an input voltage fluctuation range of 40V to 60V. The FSBB operates in closed-loop control mode, stabilizing the output voltage at 12V when faced with a wide range of input voltage fluctuations.

[0035] like Figure 3 As shown, the optimized multi-resonant switched slot converter (OMRSTC) disclosed in this embodiment of the invention, by sharing inductor elements with the same operating state, converts... Figure 2 The L in the traditional 4:1 switching resonant slot circuit shown is... r1 L r2 Use an inductor L r To reduce the number of passive components in the circuit, alternatives are used. To minimize the impact of passive component parameter errors on the circuit, inductor L... r A small capacitor C2, much smaller than the resonant capacitor, is connected in parallel across the two ends, and the tolerance problem is solved using a second resonant cavity. In the 4:1 optimized multi-resonant switching slot circuit (OMRSTC) of this embodiment, C2 << C r1 =C r2 <<C F Therefore, C is selected. r1 =C r2 =4.7μF, C2=47nF, L r =50nH. Let C be... r1 C r2 With L r The common resonance frequency is f r C2 and L r The second resonant frequency of the operation is f r2 ,

[0036]

[0037]

[0038] like Figure 4 As shown, in this embodiment of the invention, the operating frequency f of OMRSTC is... s Slightly higher than the resonant frequency f r Take f s =250kHz, the circuit has four operating modes. The modes are as follows: Figure 4 As shown in (a), Q 1a Q 2a Q 3a Q 4aActivated simultaneously, Q 1b Q 2b Q 3b Q 4b When synchronously turned off, the input voltage is connected in series with the resonant cavity and simultaneously supplies power to the load R. L Power supply, although L r It also resonates with C2, but because C2 has very little energy, its second resonant frequency f is low. r2 Much greater than the main resonant frequency f r The effect of capacitor C2 is negligible; its relevant operating waveforms are shown below. Figure 5 As shown by the red curve; mode two is as follows Figure 4 As shown in (b), all the switching transistors are off at this time, and only the second resonant cavity is working. The capacitor C2 is the inductor L. r The residual current I Lr Provide a loop by setting the dead time. Make the remaining resonant inductor current I Lr The resonant tank current i flows completely through capacitor C2. tank It can perform the reverse process without loss; the relevant working waveforms are shown below. Figure 5 Pink curve; Modal triad Figure 4 As shown in (c), Q 1a Q 2a Q 3a Q 4a Synchronous shutdown, Q 1b Q 2b Q 3b Q 4b Synchronous activation, resonant cavity reverse resonance towards load R L Power supply; the effect of capacitor C2 is also ignored in this process; the relevant operating waveforms are shown in [reference needed]. Figure 5 Blue curve; Modal quadrilateral Figure 4 As shown in (d), all switches are turned off, and the dead time t d The internal capacitor C2 provides a circuit for the residual inductor current; its relevant operating waveforms are shown below. Figure 5 Green curve.

[0039] In a four-switch Buck-Boost circuit, Q1 and Q2 conduct complementaryly with a duty cycle of d1, and Q3 and Q4 conduct complementaryly with a duty cycle of d2. Therefore, the voltage gain M of the entire converter can be obtained as follows:

[0040]

[0041] like Figure 6 As shown, the four-switch Buck-Boost circuit in this embodiment of the invention employs a single-voltage loop control with input voltage feedforward, where Hv(s) is the feedback coefficient of the output voltage, and G... vc(s) is the voltage loop controller, G M (s) is the PWM modulation function. When the input voltage is 60V, which is higher than the rated input voltage of 48V, the control circuit generates four PWM signals by superimposing the difference signal generated by comparing the output voltage sample value and the voltage reference value with the sampled input voltage signal and sending it to the voltage regulator. This generates the duty cycle d1 = 0.5, d2 = 0, making M = V. o / V in =0.5, FSBB operates in Buck mode, and the output voltage V o Maintain at 12V. When the input voltage is below the rated value, the FSBB operates in Boost mode, and its control process is similar.

[0042] like Figure 7 As shown, Figure 2 In the worst-case scenario, the traditional 4:1 switching resonant slot converter in the middle, i.e., the capacitor C r1 When the deviation from the standard value is 20%, the resonant tank current (i) tank The waveform changes are very obvious. When there are errors in the capacitor parameters, especially when the capacitance value is too small, the switching frequency becomes lower than the resonant frequency, soft switching is lost, and the resonant tank current (i) changes significantly. tank An increase in the effective value will result in higher conduction losses and reduce the efficiency of the converter in low-voltage, high-current applications at intermediate bus converters.

[0043] Figure 8 Showing Figure 3 In this embodiment of the invention, 4:1OMRSTC is used in the worst-case scenario, i.e., capacitor C. r1 Capacitor C r2 The resonant tank current (i) with a deviation of 20% from the standard value tank Waveform comparison. Figure 7 Capacitor C r1 The resonant tank current (i) changes by 20% tank From the changes in the capacitance C2 and the resonant inductance L, it can be seen that the introduction of the second resonant cavity connects the capacitor C2 with the resonant inductor L. r After parallel connection, the capacitance deviation affects the resonant tank current (i). tank The impact of the problem is greatly reduced, which verifies that the present invention can still achieve the anti-interference performance of passive component parameter errors even with only one resonant inductor and only one second resonant cavity.

[0044] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An optimized multi-resonant switching slot converter based on partial power regulation, characterized in that: This includes (1) an optimized multi-resonant switching slot circuit (OMRSTC) and (2) a four-switch buck-boost circuit (FSBB), where the OMRSTC requires only one resonant inductor L. r With a second resonant cavity, the operating performance of a traditional multi-resonant switch slot circuit can be met. The optimized multi-resonant switch slot circuit (OMRSTC) described in (1) includes four wing-side switches Q. 1a Q 1b Q 2a Q 2b 4 rectifier-side switching transistors Q 3a Q 3b Q 4a Q 4b Two resonant capacitors C r1 and C r2 1 resonant inductor L r One bypass capacitor C2 and one clamping capacitor C F ; Q 1a The current input terminal is electrically connected to the positive terminal of the voltage source; Q 1a Q 1b Q 2a Q 2b The current output terminal and current input terminal are electrically connected in sequence; Q 3a The current output terminal and Q 3b Electrical connection of current input terminal, Q 3b The current output terminal is electrically connected to the negative terminal of the voltage source; Q 4b The current output terminal and Q 4a Electrical connection of current input terminal, Q 4a The current output terminal is electrically connected to the negative terminal of the voltage source; C r1 One end and Q 1a Electrical connection of the current output terminal; C F One end and Q 1b Electrical connection of the current output terminal; C F The other end and Q 4a Electrical connection of the current input terminal; C r2 One end and Q 2a Electrical connection of the current output terminal; L r One end and C r1 and C r2 Electrical connection of current output terminal, L r The other end and Q 3b Electrically connected to the current input terminal; one end of C2 is connected to C r1 and C r2 The current output terminal of C2 is electrically connected; the other end of C2 is connected to Q. 3b Electrical connection of the current input terminal; The (2) four-switch Buck-Boost circuit (FSBB) includes four switching transistors Q1, Q2, Q3, and Q4, and a capacitor C. b With inductor L b ; C b One end and Q 2b Electrical connection of the current output terminal; C b The other end is electrically connected to the negative terminal of the voltage source; inductor L b One end of the inductor is electrically connected to the current output terminal of Q1; b The other end is electrically connected to the current input terminal of Q3; the current input terminal of Q1 is connected to Q... 2b The current output terminal of Q1 is electrically connected to the current input terminal of Q2; the current output terminal of Q2 is electrically connected to the negative terminal of the voltage source; the current output terminal of Q3 is electrically connected to the negative terminal of the voltage source; the current input terminal of Q3 is electrically connected to the current output terminal of Q4. Q 3a Q 4b The current input terminal of Q1 serves as the output terminal of the (1) optimized multi-resonant switch slot circuit (OMRSTC); the current input terminal of Q4 serves as the output terminal of the (2) four-switch buck-boost circuit (FSBB); Q 3a Q 4b It is electrically connected to the current input terminal of Q4 to supply power to the load.

2. The optimized multi-resonant switching slot converter based on partial power regulation according to claim 1, characterized in that: The optimized multi-resonant switching slot circuit (OMRSTC) described in (1) satisfies the following constraints during parameter design; C r1 and C r2 Equal capacitance values; C2 << C r1 =C r2 <<C F； Remember C r1 C r2 With L r The common resonance frequency is f r C2 and L r The second resonant cavity frequency of the operation is f r2 , In the optimized multi-resonant switching slot circuit (OMRSTC) described in (1), Q 1a Q 2a Q 3a Q 4a For the same driving signal, Q 1b Q 2b Q 3b Q 4b For the same driving signal, Q 1a and Q 1b Complementary conduction, with a certain dead time t. d The switching frequency is f s The OMRSTC circuit operates in open-loop mode, uses fixed-frequency control, and satisfies the following constraints: f s >f r and In the aforementioned (2) four-switch Buck-Boost circuit (FSBB), Q1 and Q2 are complementary in conduction, with Q1 having a duty cycle of d1; Q3 and Q4 are complementary in conduction, with Q3 having a duty cycle of d2; the switching frequencies of Q1, Q2, Q3, and Q4 are consistent, denoted as f. s f s The switching frequency f of the switching transistor in the optimized multi-resonant switching slot circuit (OMRSTC) is compared with that in (1). s equal; The (2) four-switch Buck-Boost circuit (FSBB) uses a single-voltage loop control with input voltage feedforward. In the voltage regulator, the difference signal generated by comparing the output voltage sample value with the voltage reference value is superimposed with the sampled input voltage signal to generate four PWM signals, which are respectively supplied to Q. 1a Q 2a Q 3a Q 4a By controlling the duty cycles d1 and d2, the dynamic response of the output voltage to the input voltage is achieved.

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