CN114337300B - Digital realization system and method for LCC resonant converter time phase shift control - Google Patents
Digital realization system and method for LCC resonant converter time phase shift control Download PDFInfo
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Abstract
The invention discloses a digital realization system and a digital realization method for time phase shift control of an LCC resonant converter, wherein the digital realization system comprises the LCC resonant converter, a zero crossing detection circuit and a digital controller; the LCC resonant converter comprises an inversion full bridge, an LCC resonant cavity circuit, a transformer and a rectifying circuit, and the output power of the LCC resonant converter is controlled by driving four switching tubes of the inversion full bridge; the zero-crossing detection circuit is responsible for detecting zero-crossing points of resonant current in the resonant cavity and providing time base signals for time phase-shifting control; the digital controller realizes time phase shift control of the LCC resonant converter based on the previous zero crossing detection signal. The invention improves the dynamic response speed of the LCC resonant converter, and simultaneously allows the LCC resonant converter to have higher input voltage ripple suppression on the premise of realizing a soft switch in a wide load range aiming at the situation that the LCC resonant converter is applied to a high-power occasion, thereby improving the steady-state performance and efficiency of the LCC resonant converter.
Description
Technical Field
The invention belongs to the field of power electronic converters, and particularly relates to a digital implementation system and method for time phase shift control of an LCC resonant converter.
Background
With the rapid development of power electronic technology and semiconductor technology in recent years, the application occasions of power electronic converters are wider and wider, the voltage output level of the converters is also continuously improved, and the high-voltage direct current power supply is widely applied to various occasions such as electrostatic dust collection, X-ray machines, nuclear magnetic resonance, high-energy physical experiments and the like.
The prior high-voltage direct-current power supply has higher requirements on voltage output level, and also provides related standards for indexes such as power density, volume, efficiency and the like of the power supply. In order to improve the performance of power supplies, resonant converters have received considerable attention from both academia and industry because of their advantage of being able to realize a wide load range soft switching without the need for auxiliary circuitry. Among them, LCC resonant converters are widely used in high-voltage dc power supplies because of their wider output voltage range and the ability to utilize the parasitic parameters of the high-voltage transformer to participate in resonance.
The main flow control method for the LCC resonant converter is mainly divided into direct frequency conversion control and phase shift control, wherein the phase shift control is difficult to obtain higher voltage gain, and a hysteresis bridge arm is easy to lose zero voltage open condition (ZVS) in light load; although the variable frequency control can obtain wider output gain, because the LCC resonant converter has a low frequency pole, the LCC resonant converter is a multi-pole high-order system, the controller is difficult to design, and the wide frequency variation range can also make the magnetic element difficult to design.
Disclosure of Invention
The invention aims to provide a digital implementation system and a digital implementation method for time phase shift control of an LCC resonant converter, which optimize the design of a controller of the LCC resonant converter in a variable frequency mode, improve the dynamic response speed of the converter, and eliminate the low-frequency pole of the LCC resonant converter by detecting the zero crossing point of resonant current and introducing a current inner loop so that the low-frequency band is similar to a first-order system, thereby further improving the bandwidth of the converter.
The technical solution for realizing the purpose of the invention is as follows: a digital implementation system for LCC resonant converter time phase shift control comprises an LCC resonant converter, a zero crossing detection circuit ZCD and a digital controller, wherein:
The LCC resonant converter is a main power circuit and comprises an inversion full bridge, an LCC resonant cavity circuit, a high-voltage transformer and a rectifying circuit, wherein parasitic parameters of the high-voltage transformer are converted into resonance capacitance and resonance inductance in the resonant cavity circuit, power conversion is realized by controlling the switches of four switching tubes Q1-Q4 of the inversion full bridge, the switching tubes on the same bridge arm cannot be simultaneously turned on, namely Q1 and Q2 are complementarily conducted, and Q3 and Q4 are complementarily conducted;
The zero-crossing detection circuit ZCD is used for detecting the positive and negative zero-crossing points of the resonant current iLr in the resonant cavity circuit, outputting ZCD synchronous signals and providing a time reference for a subsequent digital controller to realize a time phase shift control strategy;
And the digital controller is used for realizing time phase shift control, regulating an input error signal through a PI control algorithm, outputting PWM waves and controlling the switching time sequence of the switching tubes Q1-Q4 through the TSC module.
Further, the resonant cavity circuit of the LCC resonant converter is composed of a series resonant capacitor Cr, a series resonant inductor Lr and a parallel resonant capacitor Cp, and the output side power is adjusted by controlling the switches of the switching transistors Q1 to Q4.
Further, the digital controller is based on a digital signal processing chip, and performs digital processing on the input output voltage error amount and the ZCD synchronous signal, and performs operation by using the digital signal processing chip to realize corresponding time phase shift control.
Further, the system realizes open loop control on one hand, and controls the switching frequency of the LCC resonant converter by giving a fixed value of a period register so as to realize power conversion of the LCC resonant converter, and also realizes closed loop control on the other hand, and an error signal obtained by comparing a reference voltage Vref with the actual output voltage Vo of the LCC resonant converter is input into the digital controller as a period register value, and the output of the LCC resonant converter is subjected to no-static-difference regulation through a PI control algorithm so as to realize power conversion of the converter.
Further, the open loop control and the closed loop control active power entering the resonant cavity circuit from the input side by controlling time Td between a resonant current zero crossing point in the resonant cavity circuit and the switching-off of the switching tube, so that the output power of the LCC resonant converter is controlled, meanwhile, the Td is required to be kept positive all the time, the resonant current resonant zero crossing point is inductive in the resonant cavity before the switching tube is switched off, and the switching tubes Q1-Q4 on the primary side can realize zero voltage switching-on.
A digital implementation method for LCC resonant converter time phase shift control constructs the digital implementation system for LCC resonant converter time phase shift control, uses a digital controller to realize the time phase shift control of the LCC resonant converter, and comprises the following specific processes:
when the switching tubes Q1 and Q4 are on, configuring a time base module in an enhanced pulse width modulation module in the digital controller into an up-counting mode and starting counting;
When the time base synchronous input of the time base module receives a time base signal sent by the zero crossing detection circuit ZCD, resetting the time base module count in the digital controller to an initial phase and restarting the count;
when the given error amount is counted, namely the value stored in the period register, the time base module is reset, and the action limiting module in the digital controller acts, so that the action limiting module is configured to turn over PWM waves when an event occurs, turn over the output driving level, output low level to the driving circuits of the Q1 and Q4, turn off the switching tubes Q1 and Q4, turn on the switching tubes Q2 and Q3 after dead time, and enable the conduction time of the Q2 and Q3 tubes to be identical with the conduction time of the Q1 and Q4 tubes through the peripheral logic circuit and the isolation chip.
Compared with the prior art, the invention has the remarkable advantages that: (1) Aiming at the condition that a plurality of poles exist in an LCC resonant converter system under the traditional direct frequency conversion control, the low-frequency poles are eliminated by introducing time phase-shifting control, so that the system is similar to a first-order system, the design of a controller is optimized, and the bandwidth of the converter is conveniently improved; (2) The dynamic response speed of the LCC resonant converter is improved, and the input voltage ripple suppression capability of the LCC resonant converter can be improved; (3) The time phase shift control strategy is optimized through the digital controller, so that an additional analog circuit is not needed, and the time phase shift control strategy can be realized only through configuring the digital controller; (4) Compared with other types of current-type LCC control strategies, the digital time phase shift control strategy does not need a high-precision current sensor, and is beneficial to reducing the circuit cost.
Drawings
Fig. 1 is a block diagram of a digital control based on LCC resonant converter time phase shift control.
Fig. 2 is a timing diagram for normal operation under digital control based on LCC resonant converter time phase shifting control.
Fig. 3 is a control flow diagram under LCC based resonant converter time phase shift control.
Fig. 4 is a diagram of a system bode under direct conversion control based on an LCC resonant converter.
Fig. 5 is a diagram of a system bode under digital control based on LCC resonant converter time phase shift control.
Fig. 6 is a simulation diagram of a set of output current voltage under direct frequency conversion control based on an LCC resonant converter.
Fig. 7 is a set of simulation graphs of output current voltage under LCC resonant converter time phase shift control.
Fig. 8 is fundamental approximation modeling for an LCC resonant converter.
Fig. 9 is a graph of LCC resonant converter voltage output gain versus switching frequency.
Fig. 10 is a graph of LCC resonant converter impedance angle versus switching frequency.
Detailed Description
The invention relates to a digital implementation system and a digital implementation method for time phase shift control of an LCC resonant converter. The switching tube conduction of the LCC resonant converter is controlled by a digital controller (DIGITAL SIGNAL processor, DSP) and a zero-crossing detection circuit (Zero Cross Detection, ZCD). The LCC resonant converter is a main power circuit and consists of an inversion full bridge, an LCC resonant cavity circuit, a transformer and a rectifying circuit, and the output power of the LCC resonant converter is controlled by driving four switching tubes of the inversion full bridge. The zero-crossing detection circuit ZCD is responsible for detecting the zero crossing point of the resonant current in the resonant cavity and providing time base signals for time phase shift control, and the digital controller realizes the time phase shift control of the LCC resonant converter based on the ZCD signals detected by the previous zero crossing.
The invention discloses a digital realization system for time phase shift control of an LCC resonant converter, which comprises the LCC resonant converter, a zero crossing detection circuit ZCD and a digital controller, wherein:
The LCC resonant converter is a main power circuit and comprises an inversion full bridge, an LCC resonant cavity circuit, a high-voltage transformer and a rectifying circuit, wherein parasitic parameters of the high-voltage transformer are converted into resonance capacitance and resonance inductance in the resonant cavity circuit, power conversion is realized by controlling the switches of four switching tubes Q1-Q4 of the inversion full bridge, the switching tubes on the same bridge arm cannot be simultaneously turned on, namely Q1 and Q2 are complementarily conducted, and Q3 and Q4 are complementarily conducted;
The zero-crossing detection circuit ZCD is used for detecting the positive and negative zero-crossing points of the resonant current iLr in the resonant cavity circuit, outputting ZCD synchronous signals and providing a time reference for a subsequent digital controller to realize a time phase shift control strategy;
And the digital controller is used for realizing time phase shift control, regulating an input error signal through a PI control algorithm, outputting PWM waves and controlling the switching time sequence of the switching tubes Q1-Q4 through the TSC module.
As a specific embodiment, the resonant cavity circuit of the LCC resonant converter is composed of a series resonant capacitor Cr, a series resonant inductor Lr and a parallel resonant capacitor Cp, and the output side power is adjusted by controlling the switches of the switching transistors Q1 to Q4.
As a specific embodiment, the digital controller is based on a digital signal processing chip, and performs digital processing on the input output voltage error amount and the ZCD synchronous signal, and performs operation by using the digital signal processing chip to realize corresponding time phase shift control.
As a specific embodiment, the system, through configuration of a digital controller, on one hand, realizes open-loop control, and given a fixed value of a period register (Time Base Period Register, TBPRD), controls the switching frequency of the LCC resonant converter, so as to realize power conversion of the LCC resonant converter, and on the other hand, also realizes closed-loop control, and inputs an error signal obtained by comparing a reference voltage vref with an actual output voltage Vo of the LCC resonant converter as a period register value into the digital controller, and performs no-static-difference adjustment on the output of the LCC resonant converter through a PI control algorithm, so as to realize power conversion of the converter.
As a specific embodiment, the open loop control and the closed loop control active power entering the resonant cavity circuit from the input side by controlling time Td between a zero crossing point of resonant current in the resonant cavity circuit and the turn-off of the switching tube, so as to control output power of the LCC resonant converter, and meanwhile, the Td needs to be kept positive all the time, and the zero crossing point of resonant current is inductive in the resonant cavity before the switching tube is turned off, so that zero voltage turn-on (Zero Voltage Switching, ZVS) of switching tubes Q1 to Q4 on the primary side can be realized.
The invention discloses a digital implementation method of LCC resonant converter time phase shift control, which constructs a digital implementation system of LCC resonant converter time phase shift control, and uses a digital controller to realize the time phase shift control of the LCC resonant converter, and the specific process is as follows:
Configuring a time base module in an enhanced pulse width modulation module (Enhanced Pulse Width Modulator, EPWM) in the digital controller to an up-count mode and starting counting when the switching transistors Q1, Q4 are on;
when the time base synchronization input (Time Base Synchronization Input, SYNCI) of the time base module receives the time base signal sent by the zero crossing detection circuit ZCD, the time base module count in the digital controller is reset to the initial phase and the count is restarted;
When a given error amount, namely a value stored in a period register (TBPRD), is counted, the time base module is reset and an Action limiting module (AQ) in the digital controller acts, so that the Action limiting module (AQ) is configured to turn over a PWM wave (Toggle Epwm) when an event occurs, the output driving level is turned over, the driving circuit of Q1 and Q4 is output with a low level, the switching tubes Q1 and Q4 are turned off, and after dead time passes, the switching tubes Q2 and Q3 are turned on, and the conduction time of the Q2 and Q3 tubes is the same as the conduction time of the Q1 and Q4 tubes through the peripheral logic circuit and the isolation chip.
The present invention will be further described with reference to the drawings and the specific embodiments.
Examples
As shown in fig. 1, the method for realizing the digitization of the time phase shift control based on the LCC resonant converter comprises the following steps: LCC resonant converter, zero-crossing detection circuit ZCD, digital controller and time phase shift control strategy digital implementation method. Wherein: the LCC resonant converter is a main controlled object and plays a role of a power converter. The zero-crossing detection circuit ZCD is used for detecting the zero crossing point of the resonant current in the resonant cavity and providing a time base signal for the digital controller. The digital controller is used for realizing a time phase shift control strategy for the LCC resonant converter, controlling the driving of a switching tube of the LCC resonant converter and realizing power conversion.
The LCC resonant converter is shown in fig. 1, and mainly comprises an inverter full bridge, an LCC resonant cavity, a transformer and a rectifying circuit. The inverter full-bridge circuit is a switching circuit formed by switching tubes Q1, Q2, Q3 and Q4 in fig. 1, and mainly plays a role of converting direct current at an input side into alternating current to be supplied to a resonant cavity. The resonant cavity circuit mainly comprises a series resonant capacitor Cr, a series resonant inductor Lr and a parallel resonant capacitor Cp in FIG. 1, and is used for forming an inductive resonant cavity, so that the current in the resonant cavity lags behind the voltage Vab between bridge arms, and a large enough current is provided for the parallel diodes of the switching tubes Q1 to Q4 to be switched on in advance, so that the switching tubes realize Zero Voltage Switching (ZVS). The transformer is equivalent to an ideal transformer as shown in fig. 1, and parasitic parameters such as distributed capacitance, leakage inductance and the like are all converted into resonance elements on the primary side, and participate in resonance when the transformer works. As shown in fig. 1, the secondary side rectifying circuit is composed of diodes D1, D2, D3, D4 and an output filter capacitor, and mainly plays a role of converting an ac current in the resonant cavity into a dc current and filtering out high-frequency components in the dc current at the output side for output.
The resonant current zero-crossing detection circuit (ZCD) can compare the resonant current with zero level through a comparator, detect the forward and reverse zero crossing points of the resonant current in the resonant cavity, and give a ZCD synchronous signal to provide a time reference for the subsequent digital controller.
The digital controller consists of a digital signal processing chip (DSP) and a peripheral circuit, and is used for converting analog signals into digital signals and processing the digital signals, and the peripheral circuit provides various peripheral devices for the digital signal processing chip, so that the digital signal processing chip is more convenient to use in the fields of control, signal processing and the like.
The time phase shift control strategy based on the LCC resonant converter is a system which consists of the parts together as shown in fig. 1, on one hand, open loop control can be realized through the configuration of a digital controller, the switching frequency of the converter is given TBPRD, so that the power conversion of the converter can be realized, on the other hand, closed loop control can also be realized, an error signal obtained by comparing the reference voltage Vref with the actual output voltage Vo is input into the digital controller as TBPRD, and no static difference adjustment is carried out on the output of the LCC resonant converter through programming a PI control algorithm, so that the power conversion of the converter is realized. Whether the open loop control or the closed loop control is carried out, the active power entering the resonant cavity from the input side is controlled by controlling the time Td between the zero crossing point of the resonant current in the resonant cavity and the turn-off of the switching tube, so that the output power of the LCC resonant converter is controlled, and meanwhile, the Td is required to be kept positive all the time, so that the zero crossing point of the resonant current resonance is ensured to be inductive in the resonant cavity before the switching tube is turned off, and ZVS can be realized by the switching tubes Q1 to Q4 on the primary side.
The time phase shift control digital implementation method based on the LCC resonant converter comprises the following steps:
step1, an LCC resonant converter bears the task of power conversion and is a main control object of the invention;
step 2, a zero detection circuit ZCD can detect positive and negative zero crossing points of resonant current in the resonant cavity, and gives out ZCD synchronous signals to provide a time reference for a subsequent digital controller;
Step 3, the digital controller mainly comprises a digital processing chip (DSP) and peripheral circuits thereof, and realizes Time phase shift control of the LCC resonant converter by configuring a Time-based (TB) module and an Action-qualitier (AQ) module in the DSP, wherein the specific steps are as follows: when the switching transistors Q1, Q4 are turned on, a Time Base (TB) module in the digital controller is configured in an up-count mode and starts counting, and the time base signal sent by the zero crossing detection circuit (ZCD) is received by the SYNCI of the digital controller, so that the time base module in the digital controller is reset to an initial phase and restarted to count, when the input error amount TBPRD is counted, the time base module is reset and the AQ module in the digital controller acts, so that the AQ module in the digital controller is configured as Toggle Epwm, the output driving level is turned over, so that the switching transistors Q1, Q4 are turned off, and after a short dead time passes, the switching transistors Q2, Q3 are turned on.
The working principle is analyzed as follows:
The time phase-shifting control is essentially a variable frequency control under fixed working conditions by controlling the time Td between the zero crossing point of the resonant current and the turn-off of the switching tube, because Td is related to the impedance angle of the resonant cavity and the impedance angle is related to the quality factor and the frequency, but by detecting the zero crossing point of the resonant current, the time phase-shifting control introduces a current inner loop, and can have faster response speed and smaller ripple wave compared with the traditional direct variable frequency control. Fig. 4 and 5 are bode diagrams of LCC resonant converters under direct frequency conversion control and time phase shift control, respectively, obtained by sweeping the simulation circuitry with matlab. As can be seen from fig. 4, the low frequency of the LCC resonant converter system under direct frequency control has a pole, which causes the controller of the LCC resonant converter to be difficult to design, and in general engineering, in order to avoid the low frequency pole, the crossover frequency is additionally reduced, which greatly reduces the dynamic response speed of the converter. In fig. 5, it can be seen that the LCC resonant converter using time phase shift control is similar to a first order system, the pole at low frequency is eliminated, and has a relatively high low frequency gain, which is beneficial to improving the dynamic response speed of the LCC resonant converter.
The time phase shift control is to control the switching tube to be switched on and off based on the zero crossing point of the resonant current, in the full-bridge LCC resonant converter, the time Td between the zero crossing point of the resonant current and the switching tube Q1 and Q4 is controlled, and meanwhile, after the short dead time, the switching tube Q2 and Q3 are switched on for the same time as the previous Q1 and Q4, so that the time phase shift is completed.
The invention applies a time phase shift control strategy to the LCC resonant converter for the first time and realizes the time phase shift control strategy through a digital controller without building an additional analog control circuit. In this example, taking DSP28335 developed by TI company as an example, a specific timing diagram is shown in fig. 2, a TB submodule in a digital controller EPWM module is configured into an up-count counting mode, when the counting module is 0, counting is started, when the counting module is TBPRD, the counter is reset, and when the counting reaches TBPRD, the output high-low level is turned over by configuring the AQ submodule, so as to output a PWM wave meeting the requirement, wherein the value of TBPRD can be directly given, or the error amount of the output voltage and the reference voltage can be input into the digital controller through a conditioning circuit, and then the value of TBPRD is given after PI algorithm calculation. It should be noted that, in order to implement the digitalized time phase shift control strategy, the zero crossing detection signal (ZCD) needs to be used as an external trigger signal, and is fed into the digital controller, and the TB submodule is configured into a mode of counting and resetting the external trigger signal, so that the time Td between the zero crossing of the resonant current and the turn-off of the switching tube can be controlled by the external trigger signal and TBPRD, thereby implementing the time phase shift control of the LCC resonant converter by using the digital controller. The specific digital control flow chart is shown in fig. 3, it can be seen that the LCC resonant converter under digital time phase shift control has strong robustness, because even if the current inner loop fails, that is, the resonant current Zero Crossing Detection (ZCD) is lost, the LCC resonant converter cannot directly work, but can be degenerated into direct frequency control, and meanwhile, if the delay count is less than TBPRD, an error joint defense module (TZ) is triggered, so that the driving level of the switching tube is forced to turn over, the situation that a certain tube is opened for a long time is avoided, and the safety of the main power board is protected.
The present invention has previously mentioned that the time phase shift control is both a current type control strategy and also a frequency conversion control in essence, and the relationship between the control quantity Td of the time phase shift control and the control quantity fs of the direct frequency conversion control is simply deduced. First, the LCC resonant converter is analyzed based on an extended fundamental wave approximation method, which is well known to those skilled in the art, and will not be described in detail herein. A fundamental equivalent model of the LCC resonant converter can be obtained here, as shown in fig. 8. The analysis of the equivalent circuit can be obtained:
Resonant cavity voltage gain:
The normalization treatment can be carried out to obtain:
Wherein the ratio of series-parallel capacitance is normalized Quality factor/>Equivalent resistance/>Where kv denotes the form factor/>Normalized angular frequency/>Series-parallel resonant angular frequency/>
Input impedance angle normalization expression:
The impedance angle of the LCC resonant converter can be plotted against the output gain versus switching frequency by Mathcad software, as shown in fig. 9 and 10. The relationship between the switching frequency and the output voltage gain and impedance angle can be seen more clearly. Meanwhile, the controlled quantity of the LCC resonant converter under the control of time phase shift has the following relation with the impedance angle of the resonant cavity:
in view of the above, it is not difficult to obtain the relationship between the phase shift time Td and the output voltage gain and impedance angle.
The invention provides a time phase shift digital control method based on an LCC resonant converter for the first time, so that the LCC resonant converter approximates to a first-order system, the dynamic response speed of the LCC resonant converter is improved, the design of a controller is optimized, and meanwhile, on the premise of realizing a soft switch in a wide load range, the LCC resonant converter is allowed to have higher input voltage ripple suppression by approximating to the first-order single-stage system, and the steady-state performance and efficiency of the LCC resonant converter are improved.
Claims (5)
1. The digital implementation system for the LCC resonant converter time phase shift control is characterized by comprising the LCC resonant converter, a zero crossing detection circuit ZCD and a digital controller, wherein:
The LCC resonant converter is a main power circuit and comprises an inversion full bridge, an LCC resonant cavity circuit, a high-voltage transformer and a rectifying circuit, wherein parasitic parameters of the high-voltage transformer are converted into resonance capacitance and resonance inductance in the resonant cavity circuit, power conversion is realized by controlling the switches of four switching tubes Q1-Q4 of the inversion full bridge, the switching tubes on the same bridge arm cannot be simultaneously turned on, namely Q1 and Q2 are complementarily conducted, and Q3 and Q4 are complementarily conducted;
The zero-crossing detection circuit ZCD is used for detecting the positive and negative zero-crossing points of the resonant current iLr in the resonant cavity circuit, outputting ZCD synchronous signals and providing a time reference for a subsequent digital controller to realize a time phase shift control strategy;
The digital controller is used for realizing time phase shift control, regulating an input error signal through a PI control algorithm, outputting PWM waves and controlling the switching time sequence of the switching tubes Q1-Q4 through a TSC module;
The digital implementation system for the time phase shift control of the LCC resonant converter uses a digital controller to realize the time phase shift control of the LCC resonant converter, and the specific process is as follows:
when the switching tubes Q1 and Q4 are on, configuring a time base module in an enhanced pulse width modulation module in the digital controller into an up-counting mode and starting counting;
When the time base synchronous input of the time base module receives a time base signal sent by the zero crossing detection circuit ZCD, resetting the time base module count in the digital controller to an initial phase and restarting the count;
when the given error amount is counted, namely the value stored in the period register, the time base module is reset, and the action limiting module in the digital controller acts, so that the action limiting module is configured to turn over PWM waves when an event occurs, turn over the output driving level, output low level to the driving circuits of the Q1 and Q4, turn off the switching tubes Q1 and Q4, turn on the switching tubes Q2 and Q3 after dead time, and enable the conduction time of the Q2 and Q3 tubes to be identical with the conduction time of the Q1 and Q4 tubes through the peripheral logic circuit and the isolation chip.
2. The system for digitally implementing the time phase shift control of the LCC resonant converter according to claim 1, wherein the resonant cavity circuit of the LCC resonant converter is composed of a series resonant capacitor Cr, a series resonant inductor Lr and a parallel resonant capacitor Cp, and the output side power is adjusted by controlling the switching of the switching transistors Q1 to Q4.
3. The system for digitally implementing the LCC resonant converter time phase shift control according to claim 1, wherein the digital controller performs the corresponding time phase shift control by performing digital processing on the input output voltage error amount and the ZCD synchronization signal based on a digital signal processing chip and performing an operation using the digital signal processing chip.
4. The digitized implementation system of the LCC resonant converter time phase shift control according to claim 1, wherein the system is configured by a digital controller, on one hand, to implement open loop control, give a fixed value to a period register, control a switching frequency of the LCC resonant converter, thereby implementing power conversion of the LCC resonant converter, and on the other hand, also implement closed loop control, input an error signal obtained by comparing a reference voltage Vref with an actual output voltage Vo of the LCC resonant converter as a period register value to the digital controller, and perform no-dead-difference adjustment on an output of the LCC resonant converter by a PI control algorithm, thereby implementing power conversion of the converter.
5. The system for digitally implementing the LCC resonant converter time phase shift control of claim 4, wherein the open loop control and the closed loop control active power entering the resonant cavity circuit from the input side by controlling time Td between a zero crossing point of resonant current in the resonant cavity circuit and turn-off of the switching tube, so as to control output power of the LCC resonant converter, and meanwhile, the output power of the LCC resonant converter needs to be kept positive all the time, the zero crossing point of resonant current is inductive in the resonant cavity before the switching tube is turned off, so that the switching tubes Q1 to Q4 on the primary side can realize zero voltage turn-on.
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| EP2942142A2 (en) * | 2014-04-02 | 2015-11-11 | Lorch Schweisstechnik GmbH | Method for regulating a welding power source |
| CN106655781A (en) * | 2016-10-19 | 2017-05-10 | 东南大学 | LCC resonant converter PWM phase shift mixed control and efficiency optimization method |
| CN109617416A (en) * | 2018-12-12 | 2019-04-12 | 华南理工大学 | LCC controlled resonant converter realizes the frequency plot autocontrol method for stablizing zero voltage switch |
| CN111107703A (en) * | 2019-12-06 | 2020-05-05 | 中国科学院电工研究所 | Current detection type synchronous rectification control method based on Rogowski coil |
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| EP2942142A2 (en) * | 2014-04-02 | 2015-11-11 | Lorch Schweisstechnik GmbH | Method for regulating a welding power source |
| CN106655781A (en) * | 2016-10-19 | 2017-05-10 | 东南大学 | LCC resonant converter PWM phase shift mixed control and efficiency optimization method |
| CN109617416A (en) * | 2018-12-12 | 2019-04-12 | 华南理工大学 | LCC controlled resonant converter realizes the frequency plot autocontrol method for stablizing zero voltage switch |
| CN111107703A (en) * | 2019-12-06 | 2020-05-05 | 中国科学院电工研究所 | Current detection type synchronous rectification control method based on Rogowski coil |
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