Optimization control method for single-phase high-frequency chain AC-DC non-electrolytic capacitor converter

Abstract

The invention discloses an optimal control method for a single-phase high-frequency chain AC-DC non-electrolytic capacitor converter, and belongs to the technical field of power electronics. In order to realize power factor correction and soft switching without a closed-loop control circuit, the circuit comprises a converter and a controller, and the converter and the controller are connected through a signal; the controller collects a signal of the converter as a feedback signal, and generates a driving pulse signal of the converter in an SPWM mode. A phase shift control method and a dead zone self-adaptive control method are adopted to control a first series switch tube, a second series switch tube, a third series switch tube and a fourth series switch tube in a primary side matrix converter and a secondary side first switch tube and a secondary side second switch tube of a secondary side rectifier; and the frequency and the pulse width of the secondary-side third switch tube and the secondary-side fourth switch tube are optimally controlled. The driving pulse signal of the pre-stage matrix converter is generated, a direct-current link energy storage capacitor of a traditional two-stage rectifying circuit is eliminated, the size is reduced, and the hardware cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to an optimization control method for a single-phase high-frequency link AC-DC electrolytic capacitor-free converter. Background Art

[0002] With the large-scale application of new energy power systems, higher requirements are put forward for power electronics optimization technology. Among them, advanced rectification technology is the current research focus. The high-frequency link AC-DC converter is a type of bidirectional isolated converter and an extended structure of the matrix rectifier. It uses a bidirectional switch array to achieve the mutual conversion of energy between AC and DC. At the same time, due to its advantages such as high power density, low harmonic content, minimal power conversion and large input voltage range, it has become a hot spot for expert research.

[0003] The simplest control method for high-frequency link AC-DC converter is single-phase shift control. Under this method, power transmission is adjusted by controlling the phase shift angle of the high-frequency AC voltage of the full bridge on both sides of the transformer. However, single-phase shift control has low controllable freedom and high current stress. When the voltage values ​​of the previous and next stages do not match, a large power reflux will be generated. The dual-phase shift control method expands the control freedom, thereby reducing power reflux and current stress. For high-frequency link AC-DC converter control, the dead time is often fixed, and it is impossible to guarantee enough time for the charging and discharging process to complete. In addition, the traditional two-stage transmission converter topology contains a large-volume voltage-stabilizing capacitor in the middle stage. The two-stage structure has low efficiency, high complexity, complex boost inductor design, and large electrolytic capacitor on the bus side. Although the existing control scheme can achieve single-stage operation, it still requires large-volume electrolytic capacitors. Therefore, it is very meaningful to study the control strategy of resonant high-frequency link AC-DC converter without electrolytic capacitor. Summary of the invention

[0004] The problem to be solved by the present invention is to realize power factor correction and soft switching without a closed-loop control circuit, and propose an optimization control method for a single-phase high-frequency link AC-DC non-electrolytic capacitor converter.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method includes a converter and a controller, and the converter and the controller are connected through a signal;

[0007] The controller collects the signal of the converter as a feedback signal, generates a drive pulse signal of the converter in an SPWM manner, and optimizes the frequency and pulse width of the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 in the primary matrix converter and the secondary side first switch tube Q1, the secondary side second switch tube Q2, the secondary side third switch tube Q3 and the secondary side fourth switch tube Q4 of the secondary rectifier by using a phase shift control method and a dead zone adaptive control method;

[0008] The converter includes an input AC power supply, an AC filter, a primary matrix converter, a high-frequency transformer, an inductor, a secondary rectifier, and a DC power supply;

[0009] The AC filter includes an AC side filter inductor L1 and a filter capacitor C1; the primary side matrix converter is composed of a primary side first bridge arm and a primary side second bridge arm connected in parallel, the primary side first bridge arm is composed of a first series switch tube S1 and a second series switch tube S2 connected in series, and the primary side second bridge arm is composed of a third series switch tube S3 and a fourth series switch tube S4 connected in series;

[0010] One end of the AC power supply is connected to the AC side filter inductor L1, the AC side filter inductor L1 is respectively connected to the filter capacitor C1 and one end of the primary matrix converter, and the other end of the filter capacitor C1 and the primary matrix converter is connected to the other end of the AC power supply;

[0011] The secondary rectifier is composed of a secondary first bridge arm and a secondary second bridge arm connected in parallel, the secondary first bridge arm is composed of a secondary first switch tube Q1 and a secondary second switch tube Q2 connected in series, and the secondary second bridge arm is composed of a secondary third switch tube Q3 and a secondary fourth switch tube Q4 connected in series; the two ends of the DC power supply are respectively connected to the two ends of the secondary rectifier;

[0012] One end of the primary side of the high-frequency transformer is connected to the midpoint of the first bridge arm of the primary matrix converter, and the other end of the primary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the primary matrix converter; one end of the secondary side of the high-frequency transformer is connected to the inductor L, and the other end of the inductor L is connected to the midpoint of the first bridge arm of the secondary rectifier, and the other end of the secondary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the secondary rectifier;

[0013] The controller collects the signal of the converter as a feedback signal and adopts phase shift control and dead zone adaptive control strategies to optimize the frequency and pulse width of the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 in the primary matrix converter and the secondary side first switch tube Q1, the secondary side second switch tube Q2, the secondary side third switch tube Q3 and the secondary side fourth switch tube Q4 of the secondary rectifier.

[0014] Furthermore, the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 are all connected in a common source manner. 11 , S 12 The second series switch tube includes a switch tube S 21 , S 22 The third series switch tube includes a switch tube S 31 , S 32 ; The fourth series switch tube includes a switch tube S 41 , S 42 .

[0015] Furthermore, the phase shift control method comprises the following steps:

[0016] In the AC side control, the modulation is performed by the triangular carrier u0, and in the DC side control, the modulation is performed by the triangular carrier u1 and u2 after the phase shift of the triangular carrier u0. The converter switching pulse is adjusted by the phase shift control, and the adjustment range of the phase shift angle φ is as follows:

[0017] 0≤φ≤π (1);

[0018] The controller first uses numerical calculation to calculate the peak current i of the primary matrix converter p , the calculation expression is:

[0019]

[0020] Where p is the transmission power and k is the voltage conversion ratio;

[0021] Solving for partial derivatives The optimal control coordinate φ op , where i p is the peak current of the primary matrix converter;

[0022] Due to the boundary conditions in equation (1), when φ op When in the operating area, φ=φ op ; When φ op When it is outside the operating area, the closest extreme point on the boundary of the operating area is selected as the optimization result;

[0023] The calculation formula of voltage conversion ratio k is:

[0024] k=v dc / nv ac

[0025] Among them, v dc is the DC power supply voltage, v ac is the AC power supply voltage;

[0026] Then calculate the phase shift φ between the DC and AC sides of the converter op , the calculation expression is:

[0027]

[0028] Furthermore, the SPWM control method also includes, in the AC side control, modulating by a triangular carrier u0, when u0 is greater than 0, the first series switch tube and the fourth series switch tube of the primary matrix converter are turned on, and when u0 is less than 0, the second series switch tube and the third series switch tube of the primary matrix converter are turned on;

[0029] In the DC side control, the triangular carrier u1 and u2 are modulated by the phase-shifted triangular carrier u0, with u1 shifted by φ relative to u0 and u2 shifted by 180° relative to u1.

[0030] The DC side is modulated by the signal u control Modulation duty cycle, defining the modulation signal u control The expression is:

[0031] u control =-|sin(ω s t)|+1 (4)

[0032] Among them, ω s is the switching angular frequency, and t is the time.

[0033] Furthermore, the dead time adaptive control strategy is set such that the dead time interval between two switches on a bridge arm should be longer than the time required for the parallel capacitor to be fully discharged, and in order to avoid excessive dead time increasing switching losses, adaptive dead time control is adopted. The relationship between the dead time and the drain-source current is as follows:

[0034]

[0035] Among them, t d is the dead time interval, V DS is the drain-source voltage, i Lrms is the effective value of the inductor current, C oss is a parallel capacitor; the dead zone time interval is calculated in real time based on the sampled inductor current.

[0036] Furthermore, the controller controls the converter to achieve 6 working states in one high frequency cycle:

[0037] Mode 1: Time period t0 to t1, S 11 , S 12 , S 41 and S 42 Turn on, form a loop with the input inductor, and Q1 and Q4 work in synchronous rectification mode;

[0038] Mode 2: During the time period from t1 to t2, the current flows through S 21 and S 22 The current rises, Q1 turns off, Q2 is turned on with zero voltage, and the current flows through the anti-parallel diode of Q2 to form a closed circuit;

[0039] Mode 3: During the time period from t2 to t3, the current starts to decrease, Q4 is turned off, and Q3 is turned on. During the dead time, the current flows through the anti-parallel diode of Q3 to form a closed circuit, so Q3 is turned on with zero voltage, and Q2 and Q3 are in synchronous rectification mode.

[0040] Mode 4: Time period t3 to t4, S 21 , S 22 , S 31 , S 32 Turn on, the converter is in rectification state, the DC side switch state does not change, and the input inductor current i g Increase, energy is transferred to the DC side, Q2 and Q3 work in synchronous rectification mode to reduce conduction loss;

[0041] Mode 5: Time period t4 to t5, the inductor current i in the converter circuit L Continue to rise, and during the dead time, the current flows through the Q4 anti-parallel diode to form a closed circuit, and Q4 is turned on at zero voltage;

[0042] Mode 6: Time period t5 to t6, S 21 , S 22 , S 31 , S 32 The current of the transformer begins to rise, the DC side current flows through Q1 and Q4 to form a closed circuit, and Q1 is turned on with zero voltage.

[0043] Beneficial effects of the present invention:

[0044] The single-phase high-frequency link AC-DC electrolytic capacitor-free converter optimization control method described in the present invention adopts SPWM to generate a driving pulse signal of a front-stage matrix converter, eliminates the DC link energy storage capacitor of a traditional two-stage rectifier circuit, reduces the volume, and saves hardware costs.

[0045] The present invention discloses an optimization control method for a single-phase high-frequency link AC-DC electrolytic capacitor-free converter. In specific operation, the controller collects voltage signals at both ends of the load as feedback signals, adopts a phase-shift modulation strategy to control power transmission in the primary matrix converter and the rectifier circuit, and uses a current peak optimization method to calculate the optimized control variables to reduce switching losses.

[0046] The optimization control method of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter described in the present invention includes adaptive dead time control to avoid the parallel capacitor from being unable to be fully discharged during the dead time interval between two switches on a line, and to avoid switching losses caused by excessive dead time. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A topological schematic diagram of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter according to the present invention;

[0048] Figure 2 This is an equivalent topological diagram of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter of the present invention;

[0049] Figure 3 A control principle diagram of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter provided by the present invention;

[0050] Figure 4 A single-phase high-frequency link AC-DC electrolytic capacitor-free converter SPWM modulation principle waveform diagram provided by the present invention;

[0051] Figure 5 A principle waveform diagram of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter optimization control method provided by the present invention within a switching cycle;

[0052] Figure 6 The current path diagram of different modes in one switching cycle of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter optimization control method of the present invention, wherein (a) is mode 1, (b) is mode 2, (c) is mode 3, (d) is mode 4, (e) is mode 5, and (f) is mode 6;

[0053] Figure 7 The experimental waveform diagrams of the optimized control method and the traditional single phase shift control method when power is transmitted from the DC side to the AC side of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter when k=1.33 of the present invention, (a) is the optimized control strategy of the present invention, and (b) is the traditional control strategy. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0055] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected specific embodiments of the present invention. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0056] In order to further understand the content, features and effects of the present invention, the following specific implementation methods are given as examples, and the attached Figure 1 -Attached Figure 7 The detailed instructions are as follows:

[0057] Embodiment 1:

[0058] A single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method includes a converter and a controller, and the converter and the controller are connected through a signal;

[0059] The controller collects the signal of the converter as a feedback signal, generates a drive pulse signal of the converter in an SPWM manner, and optimizes the frequency and pulse width of the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 in the primary matrix converter and the secondary side first switch tube Q1, the secondary side second switch tube Q2, the secondary side third switch tube Q3 and the secondary side fourth switch tube Q4 of the secondary rectifier by using a phase shift control method and a dead zone adaptive control method;

[0060] The converter includes an input AC power supply, an AC filter, a primary matrix converter, a high-frequency transformer, an inductor, a secondary rectifier, and a DC power supply;

[0061] The AC filter includes an AC side filter inductor L1 and a filter capacitor C1; the primary side matrix converter is composed of a primary side first bridge arm and a primary side second bridge arm connected in parallel, the primary side first bridge arm is composed of a first series switch tube S1 and a second series switch tube S2 connected in series, and the primary side second bridge arm is composed of a third series switch tube S3 and a fourth series switch tube S4 connected in series;

[0062] One end of the AC power supply is connected to the AC side filter inductor L1, the AC side filter inductor L1 is respectively connected to the filter capacitor C1 and one end of the primary matrix converter, and the other end of the filter capacitor C1 and the primary matrix converter is connected to the other end of the AC power supply;

[0063] The secondary rectifier is composed of a secondary first bridge arm and a secondary second bridge arm connected in parallel, the secondary first bridge arm is composed of a secondary first switch tube Q1 and a secondary second switch tube Q2 connected in series, and the secondary second bridge arm is composed of a secondary third switch tube Q3 and a secondary fourth switch tube Q4 connected in series; the two ends of the DC power supply are respectively connected to the two ends of the secondary rectifier;

[0064] One end of the primary side of the high-frequency transformer is connected to the midpoint of the first bridge arm of the primary matrix converter, and the other end of the primary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the primary matrix converter; one end of the secondary side of the high-frequency transformer is connected to the inductor L, and the other end of the inductor L is connected to the midpoint of the first bridge arm of the secondary rectifier, and the other end of the secondary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the secondary rectifier;

[0065] The controller collects the signal of the converter as a feedback signal and adopts phase shift control and dead zone adaptive control strategies to optimize the frequency and pulse width of the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 in the primary matrix converter and the secondary side first switch tube Q1, the secondary side second switch tube Q2, the secondary side third switch tube Q3 and the secondary side fourth switch tube Q4 of the secondary rectifier.

[0066] Furthermore, the first series switch tube S1, the second series switch tube S2, the third series switch tube S3 and the fourth series switch tube S4 are all connected in a common source manner. 11 , S 12 The second series switch tube includes a switch tube S 21 , S 22 The third series switch tube includes a switch tube S 31 , S 32 ; The fourth series switch tube includes a switch tube S 41 , S 42 .

[0067] Furthermore, the topology includes an AC filter, which includes an AC side filter inductor L1 and a filter capacitor C1. The voltage across the capacitor is v1, and the voltage difference between the midpoints of the AC side bridge arms is v p1 , the secondary side voltage of the high frequency transformer is v p2 , the transformer primary current is i p1 , the voltage difference at the midpoint of the DC bridge arm is v s The DC power supply is v dc , the AC power supply is v ac , the AC input current is i g . High frequency transformer T r The transformation ratio is 1:n. L is the current flowing through the inductor L.

[0068] Furthermore, the switch tubes all use SiC MOSFET.

[0069] Furthermore, the phase shift control method comprises the following steps:

[0070] In the AC side control, the modulation is performed by the triangular carrier u0, and in the DC side control, the modulation is performed by the triangular carrier u1 and u2 after the phase shift of the triangular carrier u0. The converter switching pulse is adjusted by the phase shift control, and the adjustment range of the phase shift angle φ is as follows:

[0071] 0≤φ≤π (1);

[0072] The controller first uses numerical calculation to calculate the peak current i of the primary matrix converter p , the calculation expression is:

[0073]

[0074] Where p is the transmission power and k is the voltage conversion ratio;

[0075] Solving for partial derivatives The optimal control coordinate φ op , where i p is the peak current of the primary matrix converter;

[0076] Due to the boundary conditions in equation (1), when φ op When in the operating area, φ=φ op ; When φ op When it is outside the operating area, the closest extreme point on the boundary of the operating area is selected as the optimization result;

[0077] The calculation formula of voltage conversion ratio k is:

[0078] k=v dc / nv ac

[0079] Among them, v dc is the DC power supply voltage, v ac is the AC power supply voltage;

[0080] Then calculate the phase shift φ between the DC and AC sides of the converter op , the calculation expression is:

[0081]

[0082] Furthermore, the SPWM control method also includes, in the AC side control, modulating by a triangular carrier u0, when u0 is greater than 0, the first series switch tube and the fourth series switch tube of the primary matrix converter are turned on, and when u0 is less than 0, the second series switch tube and the third series switch tube of the primary matrix converter are turned on;

[0083] In the DC side control, the triangular carrier u1 and u2 are modulated by the phase-shifted triangular carrier u0, with u1 shifted by φ relative to u0 and u2 shifted by 180° relative to u1.

[0084] The DC side is modulated by the signal u control Modulation duty cycle, defining the modulation signal u control The expression is:

[0085] u control =-|sin(ω s t)|+1 (4)

[0086] Among them, ω s is the switching angular frequency, and t is the time.

[0087] Furthermore, the dead time adaptive control strategy is set such that the dead time interval between two switches on a bridge arm should be longer than the time required for the parallel capacitor to be fully discharged, and in order to avoid excessive dead time increasing switching losses, adaptive dead time control is adopted. The relationship between the dead time and the drain-source current is as follows:

[0088]

[0089] Among them, t d is the dead time interval, V DS is the drain-source voltage, i Lrms is the effective value of the inductor current, C oss is a parallel capacitor; the dead zone time interval is calculated in real time based on the sampled inductor current.

[0090] Figure 6 This is a current path diagram of different modes in a switching cycle of a single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method of this embodiment. Assuming that all components in the converter are ideal components, according to the working principle, there are 6 working states in a high-frequency cycle. Further, the controller controls the converter to achieve 6 working states in a high-frequency cycle:

[0091] Mode 1: Time period t0 to t1, S 11 , S 12 , S 41 and S 42 Turn on, form a loop with the input inductor, and Q1 and Q4 work in synchronous rectification mode;

[0092] Mode 2: During the time period from t1 to t2, the current flows through S 21 and S 22 The current rises, Q1 turns off, Q2 is turned on with zero voltage, and the current flows through the anti-parallel diode of Q2 to form a closed circuit;

[0093] Mode 3: During the time period from t2 to t3, the current starts to decrease, Q4 is turned off, and Q3 is turned on. During the dead time, the current flows through the anti-parallel diode of Q3 to form a closed circuit, so Q3 is turned on with zero voltage, and Q2 and Q3 are in synchronous rectification mode.

[0094] Mode 4: Time period t3 to t4, S 21 , S 22 , S 31 , S 32 Turn on, the converter is in rectification state, the DC side switch state does not change, and the input inductor current i g Increase, energy is transferred to the DC side, Q2 and Q3 work in synchronous rectification mode to reduce conduction loss;

[0095] Mode 5: Time period t4 to t5, the inductor current i in the converter circuit L Continue to rise, and during the dead time, the current flows through the Q4 anti-parallel diode to form a closed circuit, and Q4 is turned on at zero voltage;

[0096] Mode 6: Time period t5 to t6, S 21 , S 22 , S 31 , S 32 The current of the transformer begins to rise, the DC side current flows through Q1 and Q4 to form a closed circuit, and Q1 is turned on with zero voltage.

[0097] Figure 2 is an equivalent topological diagram of the single-phase high-frequency link AC-DC converter without electrolytic capacitor in this embodiment; p1 and v p2 are the primary and secondary voltages of the transformer, v s is the midpoint voltage of the subsequent rectifier. p1 is the primary current of the transformer, i L is the current flowing through the inductor L.

[0098] Figure 4 This is a single-phase high-frequency link AC-DC non-electrolytic capacitor converter SPWM modulation principle waveform diagram provided in this embodiment, v s is the midpoint voltage of the post-stage rectifier. The two bridge arm drive signals of the post-stage rectifier have a 180° phase shift, u control is the DC side modulation signal, u2 and u1 are the DC side carrier signals, u0 is the AC side carrier signal, and D is the DC side duty cycle.

[0099] Figure 5 The schematic waveform diagram of a single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method provided in this embodiment within a switching cycle is shown in FIG. Figure 5 For the corresponding Figure 4 Current path diagram under different modes in a switching cycle. L is the inductor current of the converter, v p2 is the secondary voltage of the transformer. p2 and v s The phase shift angle at the midpoint is φ, and D is the DC side duty cycle.

[0100] In order to verify the effectiveness of the method of this embodiment, an experimental platform was used to conduct experimental verification and comparison on the optimization method.

[0101] Figure 7 The voltage and current waveforms of the high-frequency link electrolytic capacitor-free converter under the proposed optimized control method and the traditional single phase shift control method when the power is transmitted from the DC side to the AC side at the microsecond time scale when k = 1.33 and n = 1. It can be observed from the figure that the proposed control strategy significantly reduces the peak-to-peak value of the inductor current.

[0102] The above analysis shows that the circuit uses the current peak optimization formula to solve the optimal duty cycle, thereby reducing current stress and improving power transmission efficiency. At the same time, without relying on additional buffers or clamping circuits, single-stage power transmission is achieved, eliminating the large-volume electrolytic capacitor in the middle stage. Adaptive dead time control is used to avoid the inability of parallel capacitors to fully discharge during the dead time interval between two switches on a line, and to avoid switching losses caused by excessive dead time. The converter has a simple structure and obvious advantages, and has broad application prospects.

[0103] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0104] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method, It is characterized in that It includes a converter and a controller, and the converter and the controller are connected via a signal; The controller collects the signal of the converter as the feedback signal, generates the drive pulse signal of the converter by SPWM method, and uses the phase shift control method and the dead zone adaptive control method to control the first series switch tube S in the primary matrix converter. 1 , the second series switch tube S 2 , the third series switch tube S 3 and the fourth series switch tube S 4 And the secondary side first switch tube Q of the secondary side rectifier 1 , the second switch tube Q on the secondary side 2 , the third switch tube Q on the secondary side 3 And the fourth switch tube Q 4 Optimize the frequency and pulse width of the The converter includes an input AC power supply, an AC filter, a primary matrix converter, a high-frequency transformer, an inductor, a secondary rectifier, and a DC power supply; The AC filter includes an AC side filter inductor L 1 、Filter capacitor C 1 The primary matrix converter is composed of a primary first bridge arm and a primary second bridge arm connected in parallel, and the primary first bridge arm is composed of a first series switch tube S 1 And the second series switch tube S 2 The second bridge arm of the primary side is composed of the third series switch tube S 3 and the fourth series switch tube S 4 Series composition; One end of the AC power supply is connected to the AC side filter inductor L 1 , the AC side filter inductor L 1 Connect filter capacitors C 1 and one end of the primary matrix converter, the filter capacitor C 1 The other end of the primary matrix converter is connected to the other end of the AC power supply; The secondary rectifier is composed of a secondary first bridge arm and a secondary second bridge arm connected in parallel, and the secondary first bridge arm is composed of a secondary first switch tube Q 1 And the secondary side second switch tube Q 2 The second bridge arm of the secondary side consists of the third switch tube Q 3 And the fourth switch tube Q 4 The two ends of the DC power supply are connected in series to the two ends of the secondary rectifier respectively; One end of the primary side of the high-frequency transformer is connected to the midpoint of the first bridge arm of the primary matrix converter, and the other end of the primary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the primary matrix converter; one end of the secondary side of the high-frequency transformer is connected to the inductor L, and the other end of the inductor L is connected to the midpoint of the first bridge arm of the secondary rectifier, and the other end of the secondary side of the high-frequency transformer is connected to the midpoint of the second bridge arm of the secondary rectifier; The controller collects the signal of the converter as the feedback signal and uses the phase shift control and dead zone adaptive control strategy to control the first series switch tube S in the primary matrix converter. 1 , the second series switch tube S 2 , the third series switch tube S 3 and the fourth series switch tube S 4 And the secondary side first switch tube Q of the secondary side rectifier 1 , the second switch tube Q on the secondary side 2 , the third switch tube Q on the secondary side 3 And the fourth switch tube Q 4 The frequency and pulse width are optimized and controlled.

2. According to claim 1, a single-phase high-frequency link AC-DC non-electrolytic capacitor converter optimization control method, It is characterized in that The first series switch tube S 1 , the second series switch tube S 2 , the third series switch tube S 3 and the fourth series switch tube S 4 All of them are connected in common source mode. The first series switch tube includes a switch tube S 11 , S 12 The second series switch tube includes a switch tube S 21 , S 22 The third series switch tube includes a switch tube S 31 , S 32 ; The fourth series switch tube includes a switch tube S 41 , S 42 .

3. A single-phase high-frequency link AC-DC electrolytic capacitor-free converter optimization control method according to claim 1 or 2, It is characterized in that The phase shift control method comprises the following steps: In the AC side control, the triangular carrier u 0 Modulation is performed in DC side control through a triangular carrier u 0 The phase-shifted triangular carrier u 1 and u 2 Modulation is performed, and the converter switching pulse is adjusted by phase shift control. The adjustment range of the phase shift angle φ is as follows: 0≤φ≤π (1); The controller first uses numerical calculation to calculate the peak current i of the primary matrix converter p , the calculation expression is: Where p is the transmission power and k is the voltage conversion ratio; Solving for partial derivatives The optimal control coordinate φ op , where i p is the peak current of the primary matrix converter; Due to the boundary conditions in equation (1), when φ op When in the operating area, φ=φ op ; When φ op When it is outside the operating area, the closest extreme point on the boundary of the operating area is selected as the optimization result; The calculation formula of voltage conversion ratio k is: k=v dc / nv ac Among them, v dc is the DC power supply voltage, v ac is the AC power supply voltage; Then calculate the phase shift φ between the AC and DC sides of the converter op , the calculation expression is:

4. The optimization control method of a single-phase high-frequency link AC-DC electrolytic capacitor-free converter according to claim 3, It is characterized in that The SPWM control method also includes, in the AC side control, using a triangular carrier u 0 Modulation is performed, when u 0 When u is greater than 0, the first series switch tube and the fourth series switch tube of the primary matrix converter are turned on. 0 When it is less than 0, the second series switch tube and the third series switch tube of the primary matrix converter are turned on; In DC side control, the triangular carrier u 0 The phase-shifted triangular carrier u 1 and u 2 Modulation, u 1 Relative u 0 Phase shift φ,u 2 Relative u 1 Phase shift 180°; The DC side is modulated by the signal u control Modulation duty cycle, defining the modulation signal u control The expression is: you control =-|sin(ω s t)|+1 (4) Among them, ω s is the switching angular frequency, and t is the time.

5. The optimization control method of a single-phase high-frequency link AC-DC non-electrolytic capacitor converter according to claim 4, It is characterized in that The dead time adaptive control strategy is set to the dead time interval between two switches on a bridge arm should be longer than the time required for the parallel capacitor to be fully discharged. In order to avoid excessive dead time increasing switching losses, adaptive dead time control is adopted. The relationship between dead time and drain-source current is as follows: Among them, t d is the dead time interval, V DS is the drain-source voltage, i Lrms is the effective value of the inductor current, C oss is a parallel capacitor; the dead zone time interval is calculated in real time based on the sampled inductor current.

6. The optimization control method of a single-phase high-frequency link AC-DC non-electrolytic capacitor converter according to claim 5, It is characterized in that The controller controls the converter to achieve 6 working states in one high-frequency cycle: Mode 1: t 0 ~t 1 Time period, S 11 , S 12 , S 41 and S 42 Turn on, form a loop with the input inductor, Q 1 and Q 4 Works in synchronous rectification mode; Mode 2: t 1 ~t 2 Time period, flowing through S 21 and S 22 The current rises, Q 1 Shutdown, Q 2 Achieve zero voltage turn-on, current flows through Q 2 The anti-parallel diodes form a closed circuit; Mode 3: t 2 ~t 3 During this period, the current starts to decrease, Q 4 Shutdown, Q 3 Turn on, current flows through Q during the dead time 3 The anti-parallel diode forms a closed circuit, so Q 3 Achieve zero voltage turn-on, Q 2 and Q 3 It is synchronous rectification mode; Mode 4: t 3 ~t 4 Time period, S 21 , S 22 , S 31 , S 32 Turn on, the converter is in rectification state, the DC side switch state does not change, and the input inductor current i g Increase, energy is transferred to the DC side, Q 2 and Q 3 Works in synchronous rectification mode to reduce conduction losses; Mode 5: t 4 ~t 5 Time period, the inductor current i in the converter circuit L Continue to rise, and the current flows through Q during the dead time 4 The anti-parallel diode forms a closed circuit, Q 4 Achieve zero voltage switching; Mode 6: t 5 ~t 6 Time period, S 21 , S 22 , S 31 , S 32 and the transformer current begins to rise, the DC side current flows through Q 1 and Q 4 Form a closed circuit, Q 1 Achieve zero voltage switching.

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