CN117353543A - Control method, control device and switching power supply - Google Patents
Control method, control device and switching power supply Download PDFInfo
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- CN117353543A CN117353543A CN202311153608.3A CN202311153608A CN117353543A CN 117353543 A CN117353543 A CN 117353543A CN 202311153608 A CN202311153608 A CN 202311153608A CN 117353543 A CN117353543 A CN 117353543A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from DC input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/38—Means for preventing simultaneous conduction of switches
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/01—Resonant DC/DC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33573—Full-bridge at primary side of an isolation transformer
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
The invention discloses a control method, a control device and a switching power supply, wherein the control method comprises the following steps: detecting whether a certain switching tube in a primary side inverter circuit of an N-phase LLC topology generates a current turn-off event in a current switching period; controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period. The invention can ensure the current sharing characteristic of each phase and is beneficial to reducing the output ripple.
Description
Technical Field
The present invention relates to power supplies, and more particularly, to a control method, a control device, and a switching power supply.
Background
With the rapid development of power electronics technology, switching power supplies are evolving toward high miniaturization and high power density. The multiphase LLC topology is widely used in high-power supply due to the advantages of soft switching and low current ripple, fig. 1 is a schematic diagram of a typical three-phase LLC topology circuit, in which a primary inverter circuit includes a first bridge arm formed by a switching tube Q1 and a switching tube Q2, a second bridge arm formed by a switching tube Q3 and a switching tube Q4, and a third bridge arm formed by a switching tube Q5 and a switching tube Q6, in which a resonant branch connected by the switching tube Q1 and the switching tube Q2 includes a resonant inductance L1 and a resonant capacitance C2, in which a resonant branch connected by the switching tube Q3 and the switching tube Q4 includes a resonant inductance L3 and a resonant capacitance C3, and in which a resonant branch connected by the switching tube Q5 and the switching tube Q6 includes a resonant inductance L5 and a resonant capacitance C4.
LLC topologies are classified into two types, depending on the sampling of the feedback signal:
(1) The voltage type control, regard secondary side output voltage as the feedback signal, the deviation of this feedback signal and given value is compared with sawtooth wave and produced the control pulse after the comparator amplifies, figure 2 is a voltage type control time sequence diagram of figure 1 three-phase LLC topology, theta 1, theta 2, theta 3 represent the phase angle between the three-phase drive separately, regard first phase as the starting point, the second phase is by 120 phase place of third phase drive lag separately, namely theta 1 is 0, theta 2 is 120, theta 3 is 240, the frequency of the drive pulse of every bridge arm keeps the unanimity, this control adopts the frequency modulation control strategy, namely calculate the required operating frequency according to the feedback voltage, calculate the delay time between the drive of second phase, third phase according to the operating frequency, thus give correct switching frequency and phase delay, realize the closed-loop control that the electric parameter of LLC topology output reaches the expected value;
(2) The current type control comprises two loops, namely a current inner loop formed by taking primary side output current as a first feedback signal and a voltage outer loop formed by taking secondary side output voltage as a second feedback signal, wherein the output deviation of the voltage outer loop is taken as a given value of the current inner loop, and compared with the first feedback signal, a current turn-off event is generated, and the current turn-off event is a control quantity and is used for realizing closed loop control that the electric parameter of N-phase LLC topology output reaches an expected value.
The LLC topology controlled by the voltage type is poor in dynamic performance under the influence of the resistance power device, so that the voltage type control is difficult to meet the design requirement of the switching power supply under the condition of high dynamic performance requirement. The LLC topology controlled by the current mode reduces the LLC topology from a second-order system to a first-order system in control, widens the control bandwidth of the whole system, and improves the dynamic response performance, but the current mode control method has the problem of uneven flow in the three-phase LLC topology, so that the application is limited, and is mainly applied to the single-phase LLC topology at present.
The inventor of the application found through intensive research that the reason why the current type control method has the problem of non-current sharing in the three-phase LLC topology is that: in the three-phase LLC frequency modulation control, required working frequency, namely switching period, is calculated in advance according to feedback voltage of the switching power supply, then the angle required for delaying 120 degrees is calculated in sequence according to the calculated switching period, so that ascending and descending moments of switches of all phases are determined, however, turn-off of a switching tube is determined by resonance current and loop feedback values, so that the current mode control LLC actually works in a state with continuously changed frequency, the working period of the switching power supply cannot be determined in advance, namely the turn-on and turn-off moments of each phase under the condition of delaying 120 degrees cannot be determined, namely the fact that all the dependent times keep 120-degree phase delay cannot be ensured, and the problem of non-uniform flow among three phases is caused.
It should be noted that the above information disclosed in the background section is only for enhancement of understanding of the general background of the present application and should not be taken as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.
Disclosure of Invention
Accordingly, the technical problem to be solved by the invention is to provide a control method, a control device and a switching power supply, which can keep 120-degree phase lag between three phases when adopting current type control in a three-phase LLC topology, realize better dynamic response and ensure current sharing of each phase.
As a first aspect of the present invention, an embodiment of the control method provided has the following technical scheme:
a control method applied to a current-controlled N-phase LLC topology, N being a natural number greater than or equal to 2, wherein the control method includes:
detecting whether a certain switching tube in a primary side inverter circuit of the N-phase LLC topology generates a current turn-off event or not in a current switching period, wherein the current turn-off event is a control quantity and is used for realizing closed-loop control of an electric parameter outputted by the N-phase LLC topology reaching an expected value;
controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
Further, the current turn-off event is generated by comparing a sampling value of the resonant current in the resonant branch connected to the certain switching tube with a feedback value of the output voltage of the N-phase LLC topology, or by comparing a sampling value of the voltage across the resonant capacitor in the resonant branch connected to the certain switching tube with a feedback value of the output voltage of the N-phase LLC topology.
Further, the set values of the increase of the conduction time length of the upper switching tube and the lower switching tube of the same bridge arm in the primary side inverter circuit of the same switching period are equal.
Further, the set value of the increase of the conduction time of each switching tube in the primary side inverter circuit of different switching periods is adjustable.
Further, the upper switching tube and the lower switching tube of each bridge arm in the primary side inverter circuit of each switching period are alternately conducted, the conduction time length of the upper switching tube and the lower switching tube of each bridge arm is the same after dead time is ignored, and the phase of each bridge arm driving pulse is sequentially delayed by 360 degrees/N.
As a second aspect of the present invention, an embodiment of the control device provided has the following technical scheme:
a control apparatus applied to a current-mode controlled N-phase LLC topology, the N being a natural number greater than or equal to 2, wherein the control apparatus includes:
the detection module is used for detecting whether a certain switching tube in the primary side inverter circuit of the N-phase LLC topology generates a current switching-off event or not in the current switching period, wherein the current switching-off event is a control quantity and is used for realizing closed-loop control that the electric parameter output by the N-phase LLC topology reaches an expected value;
the processing module is used for controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
As a third aspect of the present invention, a technical solution of an embodiment of a switching power supply is provided as follows:
the switching power supply adopts a current-controlled N-phase LLC topology, wherein N is a natural number greater than or equal to 2, and is characterized by comprising the control device in the second aspect, and the control device is used for controlling the conduction time of each switching tube in the primary side inverter circuit.
Preferably, N is 3.
Compared with the prior art, the three-phase LLC topology in the embodiment of the invention adopts current type control, compared with voltage type control, the second-order system is reduced to the first-order system, the bandwidth of the system is widened, loop compensation is more convenient to carry out, the dynamic property of the system can be improved, and the current turn-off event of the current period acts on the next switching period, so that the fixed angle between each phase of the N-phase LLC topology can be kept, namely, three phases are staggered by 360 degrees/N, the current sharing characteristic of each phase is ensured, the output ripple of the switching power supply is reduced, and the reliability of the switching power supply is enhanced.
Drawings
FIG. 1 is a schematic diagram of a typical three-phase LLC topology in the background;
FIG. 2 is a voltage-type control timing diagram of the three-phase LLC topology of FIG. 1;
FIG. 3 is a flowchart of a control method according to a first embodiment of the present invention;
FIG. 4 is a timing diagram illustrating a control method for generating a current turn-off event according to a first embodiment of the present invention;
FIG. 5 is a timing diagram illustrating a control method according to a first embodiment of the present invention without generating a current shutdown event;
fig. 6 is a schematic block diagram of a control device according to a second embodiment of the present invention.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
In order to make the present application solution better understood by those skilled in the art, the following description will be made in detail and with reference to the accompanying drawings in the embodiments of the present application, it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe embodiments of the present application herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the specification, claims and drawings, when a step is described as being continued to another step, the step may be continued directly to the other step or through a third step to the other step; when an element/unit is described as being "connected" to another element/unit, the element/unit may be "directly connected" to the other element/unit or "connected" to the other element/unit through a third element/unit.
Moreover, the drawings of the present disclosure are schematic representations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus a repetitive description thereof will be omitted. Some of the block diagrams shown in the figures are functional entities and do not necessarily correspond to physically or logically separate entities. The functional entities may be implemented in software or in one or more hardware modules or integrated circuits or in different networks and/or processor devices and/or micro-control devices.
First embodiment
The embodiment provides a control method, which is applied to an N-phase LLC topology controlled by a current mode, where N is a natural number greater than or equal to 2, and the control method of the embodiment includes:
s101, detecting whether a certain switching tube in a primary side inverter circuit of an N-phase LLC topology generates a current turn-off event or not in a current switching period, wherein the current turn-off event is a control quantity and is used for realizing closed-loop control that an electric parameter output by the N-phase LLC topology reaches an expected value;
s102, controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
Fig. 1 shows a typical N-phase LLC topology applied to the control method of this embodiment, where N is 3 phases, the three-phase transformer is connected in a delta-form, the secondary side is a three-phase full-wave rectifying circuit, and the rectifying tube in OK is a diode.
It should be noted that, the application of the control method of the present embodiment to the three-phase LLC topology shown in fig. 1 is only an example, and those skilled in the art may select the number of phases of the LLC topology, the connection mode of the transformer, the type of the secondary side rectifying circuit, etc. according to the actual situation, and how to select the embodiment of the present invention is not limited.
In addition, in step S101, it is detected whether a current turn-off event is generated in a certain switching tube in the primary side inverter circuit in the current switching period of the N-phase LLC topology, and the detected switching tube is not limited in this embodiment, and a person skilled in the art may select the detected switching tube by himself, for example, for the circuit of fig. 1, any one of the switching tubes Q1 to Q6 in the primary side inverter circuit may be detected, and it is also possible to detect a plurality of switching tubes, where the durations from the turn-on to the current turn-off event generated by each detected switching tube in the same period are theoretically equal.
The current turn-off event is a control quantity, and is used for realizing closed-loop control that an electric parameter of the N-phase LLC topology output reaches a desired value, wherein the electric parameter reaches the desired value, which electric parameter reaches the desired value is not specified in the invention, and a person skilled in the art can design the electric parameter according to the need.
Preferably, the current turn-off event is generated by comparing a sampled value of the resonant current in the resonant branch to which the certain switching tube is connected with a feedback value of the output voltage of the N-phase LLC topology, or by comparing a sampled value of the voltage across the resonant capacitor in the resonant branch to which the certain switching tube is connected with a feedback value of the output voltage of the N-phase LLC topology. The feedback value of the output voltage of the N-phase LLC topology is a feedback signal in a voltage outer ring, and the magnitude of the output voltage of the secondary side can be represented.
Further, the set values of the conduction time increase of the upper switching tube and the lower switching tube of the same bridge arm in the primary side inverter circuit of the same switching period are equal, so that the same opening time of the upper switching tube and the lower switching tube can be ensured, and the current and the voltage are symmetrical.
Further, the set value of the increase of the conduction time of each switching tube in the primary side inverter circuit of different switching periods is adjustable, so that the electric parameters of the N-phase LLC topology output can reach expected values.
Further, the upper switching tube and the lower switching tube of each bridge arm in the primary side inverter circuit of each switching period are alternately conducted, the conduction time length of the upper switching tube and the lower switching tube of each bridge arm is the same after dead time is ignored, and the phase of each bridge arm driving pulse is sequentially delayed by 360 degrees/N.
The following explains the working principle of the control method of the present embodiment by taking the circuit topology of fig. 1 as an example:
FIG. 4 is a timing diagram illustrating a control method for generating a current turn-off event according to a first embodiment of the present invention. As shown in fig. 4, since the driving pulses of each two phases in the three-phase LLC topology are identical, but the phases are sequentially delayed by 120, only two phases are shown in fig. 4, and the current switching period T1 is determined by the current turn-off event in the last switching period with the driving rising edge of the switching tube Q1 in fig. 1 as the starting time, which is known, so that the current switching period T1 is known before the starting time of the driving of the switching tube Q1, and thus the turn-off time of the first phase is known; further, it is known that the driving rising edge time of the switching tube Q3 of the second phase is 1/3T 1 and the whole period of the second phase is T1; correspondingly, the driving rising edge time of the third phase switching tube Q5 is 2/3T1, and the period is also T1, so that accurate 120-degree phase delay can be kept among the three phases. Assuming that after the switching tube Q1 is turned on for the time of TIpk 1, a current turn-off event is generated by comparing a sampling value of the resonant current in the resonant branch connected with the switching tube Q1 with a feedback signal of the voltage outer ring, when the switching tube Q1 and the switching tube Q2 are both turned on for a time period of TIpk 1 in a next switching period, so that the next switching tube period t2= 2*TIpk 1+2*Tdead,Tdead is dead time, and during the time period, the switching tube Q1 and the switching tube Q2 are both turned off, so that the switching tube Q1 and the switching tube Q2 are prevented from being burnt out due to short circuit; the next switching period of the second phase may be determined to be T2 with a phase delay of 1/3T2; the next switching period of the third phase can also be determined as T2, and the phase delay is 2/3T2, so that 120-degree phase delay of the third phase can be strictly maintained when a current turn-off event occurs;
fig. 5 is a control timing chart of the control method according to the first embodiment of the present invention, as shown in fig. 5, only two phases of the control timing chart are shown, the rising edge of the driving of the switching tube Q1 in fig. 1 is taken as the starting time, the current switching period T1 is determined by the current switching event in the last switching period, which is known, so that the current switching period T1 is known before the starting time of the driving of the switching tube Q1, and thus the switching time of the first phase is known; further, it is known that the driving rising edge time of the switching tube Q3 of the second phase is 1/3T 1 and the whole period of the second phase is T1; correspondingly, the driving rising edge time of the third phase switching tube Q5 is 2/3T1, and the period is also T1, so that accurate 120-degree phase delay can be kept among the three phases. Assuming that no current turn-off event occurs during the period when the switching tube Q1 is turned on Ton1, in the next switching period, the switching tube Q1 and the switching tube Q2 are turned on Ton1+Δt for a period of time, so that the next switching tube period t2=2× (Ton 1+Δt) +2×tdead; the next switching period of the second phase may be determined to be T2 with a phase delay of 1/3T2; the next switching period of the third phase may also be determined to be T2 with a phase delay of 2/3T2, thus ensuring that the three phases remain exactly 120 ° phase delay in the absence of a current turn-off event.
As can be seen from the analysis of the above working principle, the difference between the working frequency of the embodiment and the method of fig. 2 is that the working frequency of fig. 2 is only determined by the feedback signal of the secondary output voltage, but the working frequency of the embodiment is not only related to the feedback signal of the outer voltage loop but also related to the feedback signal of the inner current loop, the control method of the embodiment reduces the second order system to the first order system relative to the voltage type control, widens the bandwidth of the system, is more convenient for loop compensation, can promote the dynamic performance of the system, and can keep a fixed angle between each phase of the N-phase LLC topology by acting the current turn-off event of the current period on the next switching period, namely three-phase interleaving of 360 °/N, thereby ensuring the characteristic of each phase current flow, being beneficial to reducing the output ripple of the switching power supply and enhancing the reliability of the switching power supply.
Second embodiment
The embodiment provides a control device, which is applied to an N-phase LLC topology controlled by a current mode, where N is a natural number greater than or equal to 2, and the control device includes:
the detection module is used for detecting whether a certain switching tube in the primary side inverter circuit of the N-phase LLC topology generates a current turn-off event or not in the current switching period, wherein the current turn-off event is a control quantity and is used for realizing closed-loop control that the electric parameter output by the N-phase LLC topology reaches an expected value;
the processing module is used for controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
The present embodiment is a control device corresponding to the control method of the first embodiment, and has the same advantageous effects, and further refinements, improvements, and the like in the control method of the first embodiment are applicable to the control device of the present embodiment.
Third embodiment
The embodiment provides a switching power supply, which adopts a current-controlled N-phase LLC topology, where N is a natural number greater than or equal to 2, where the switching power supply includes any one of the control devices in the second embodiment, and is configured to control the on duration of each switching tube in a primary inverter circuit.
Preferably, N is 3, and the phase number increase can reduce the LLC output ripple current, but can greatly increase the volume of the switching power supply, so that the optimization of the switching power supply volume and the output ripple current can be better realized when N is 3.
The above-mentioned embodiments of the present invention are not intended to limit the scope of the present invention, and the embodiments of the present invention are not limited thereto, and all kinds of modifications, substitutions or alterations made to the above-mentioned structures of the present invention according to the above-mentioned general knowledge and conventional means of the art without departing from the basic technical ideas of the present invention shall fall within the scope of the present invention.
Claims (8)
1. A control method applied to a current-controlled N-phase LLC topology, said N being a natural number greater than or equal to 2, the control method comprising:
detecting whether a certain switching tube in a primary side inverter circuit of the N-phase LLC topology generates a current turn-off event or not in a current switching period, wherein the current turn-off event is a control quantity and is used for realizing closed-loop control of an electric parameter outputted by the N-phase LLC topology reaching an expected value;
controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
2. The control method according to claim 1, characterized in that: the current turn-off event is generated by comparing a sampling value of the resonant current in the resonant branch connected to the certain switching tube with a feedback value of the output voltage of the N-phase LLC topology, or by comparing a sampling value of the voltage across the resonant capacitor in the resonant branch connected to the certain switching tube with a feedback value of the output voltage of the N-phase LLC topology.
3. The control method according to claim 1, characterized in that: the set values of the conduction time increase of the upper switching tube and the lower switching tube of the same bridge arm in the primary side inverter circuit of the same switching period are equal.
4. The control method according to claim 1, characterized in that: the set value of the increase of the conduction time of each switching tube in the primary side inverter circuit of different switching periods is adjustable.
5. The control method according to any one of claims 1 to 4, characterized in that: the upper switching tube and the lower switching tube of each bridge arm in the primary side inverter circuit of each switching period are alternately conducted, the conduction time length of the upper switching tube and the conduction time length of the lower switching tube of each bridge arm are the same after dead time is ignored, and the phase of each bridge arm driving pulse is delayed by 360 degrees/N in sequence.
6. A control apparatus applied to an N-phase LLC topology for current mode control, the N being a natural number greater than or equal to 2, the control apparatus comprising:
the detection module is used for detecting whether a certain switching tube in the primary side inverter circuit of the N-phase LLC topology generates a current switching-off event or not in the current switching period, wherein the current switching-off event is a control quantity and is used for realizing closed-loop control that the electric parameter output by the N-phase LLC topology reaches an expected value;
the processing module is used for controlling the conduction time of each switching tube in the primary side inverter circuit of the next switching period according to the detection result: if a current turn-off event is generated by a certain switching tube in the current switching period, the time length from the turn-on time of the certain switching tube in the current switching period to the time when the current turn-off event is generated is taken as the turn-on time length of each switching tube in the primary inverter circuit of the next switching period; if the current turn-off event is not generated in the certain switching tube in the current switching period, the turn-on duration of each switching tube in the primary side inverter circuit of the current switching period is increased by a set value and then used as the turn-on duration of each switching tube in the primary side inverter circuit of the next switching period.
7. A switching power supply adopts a current-controlled N-phase LLC topology, wherein N is a natural number greater than or equal to 2, and the switching power supply is characterized by comprising the control device of claim 6, and the control device is used for controlling the on-time of each switching tube in a primary side inverter circuit.
8. The switching power supply of claim 7 wherein: and N is 3.
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| CN202311153608.3A CN117353543A (en) | 2023-09-07 | 2023-09-07 | Control method, control device and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311153608.3A CN117353543A (en) | 2023-09-07 | 2023-09-07 | Control method, control device and switching power supply |
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