A soft switching control method, device, system and readable storage medium of a converter

Abstract

The application provides a soft switching control method, device and system of a converter and a readable storage medium. The method comprises: calculating a first modulation parameter of the converter and generating a plurality of first target drive signals based on the first modulation parameter, so as to control corresponding first target switching tubes to be turned on or turned off through the first target drive signals, and realize closed-loop control of output voltage and input current of the converter; calculating a second modulation parameter of the converter after closed-loop control based on the first modulation parameter; wherein one of the first modulation parameter and the second modulation parameter is a modulation ratio and the other is a phase shift ratio; generating a plurality of second target drive signals based on the second modulation parameter; wherein the drive signal corresponding to the modulation ratio is used for controlling each switching tube of a matrix circuit to be turned on or turned off, and the drive signal corresponding to the phase shift ratio is used for controlling each switching tube of a full-bridge circuit to be turned on or turned off. Through implementation of the application scheme, soft switching of all switching tubes in a full-voltage range and a full-load range can be realized.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a soft-switching control method, device, system, and readable storage medium for a converter. Background Technology

[0002] In recent years, the global new energy vehicle market has grown rapidly, and the demand for high-performance fast charging / supercharging has become increasingly urgent. Among related technologies, electric vehicle charging systems typically employ a two-stage architecture. Its main drawbacks are twofold: first, power passes through two stages of converters, thus limiting efficiency and power density; second, the intermediate bus often requires large-capacity electrolytic capacitors, increasing system cost and reducing system lifespan and reliability. Single-stage isolated AC / DC converters, because energy is converted through a single stage, can improve efficiency and power density; they also eliminate the need for electrolytic capacitors on the intermediate bus, thus attracting increasing attention and research.

[0003] In a single-stage isolated AC / DC converter, the output voltage can be controlled by adjusting the modulation ratio of the matrix circuit and the phase shift angle of the primary and secondary sides. However, related technologies usually use a fixed modulation ratio to control the phase shift angle of the primary and secondary sides or a fixed primary and secondary side phase shift angle to control the modulation ratio. This can easily cause switching losses to the switching transistors of the converter, make it difficult to achieve soft-switching control, and easily generate electromagnetic interference (EMI). Summary of the Invention

[0004] This application provides a soft-switching control method, apparatus, system, and readable storage medium for a converter, which can at least solve the problems of difficult implementation and easy generation of electromagnetic interference in the related art.

[0005] The first aspect of this application provides a soft-switching control method for a converter; the converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer via the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit each have multiple switching transistors. The soft-switching control method includes:

[0006] After the matrix circuit is connected to three-phase AC power, the first modulation parameters of the converter are calculated based on the output voltage of the converter, and multiple first target drive signals are generated based on the first modulation parameters. Each first target drive signal is used to control the corresponding first target switch to turn on or off, so as to realize closed-loop control of the output voltage and input current of the converter.

[0007] Based on the first modulation parameter, the second modulation parameter of the converter after closed-loop control is calculated; wherein, the first modulation parameter and the second modulation parameter are, respectively, the modulation ratio and the shift ratio.

[0008] Multiple second target drive signals are generated based on the second modulation parameters; each second target drive signal is used to control the corresponding second target switch to turn on or off, so as to realize the soft switching of the converter; the first target switch and the second target switch are, respectively, switches on the matrix circuit and switches on the full-bridge circuit; the drive signal corresponding to the modulation ratio is used to control the switches on or off of the matrix circuit, and the drive signal corresponding to the shift ratio is used to control the switches on or off of the full-bridge circuit.

[0009] A second aspect of this application provides a soft-switching control device for a converter; the converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer via the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit each have multiple switching transistors. The soft-switching control device includes:

[0010] The first calculation module is used to calculate the first modulation parameters of the converter based on the output voltage of the converter after the matrix circuit is connected to three-phase AC power, and to generate multiple first target drive signals based on the first modulation parameters; wherein, each first target drive signal is used to control the corresponding first target switch to be turned on or off, so as to realize closed-loop control of the output voltage and input current of the converter.

[0011] The second calculation module is used to calculate the second modulation parameters of the converter after closed-loop control based on the first modulation parameters; wherein, the first modulation parameter and the second modulation parameter are, respectively, the modulation ratio and the shift ratio.

[0012] The generation module is used to generate multiple second target driving signals based on the second modulation parameters; wherein each second target driving signal is used to control the corresponding second target switch to turn on or off, so as to realize the soft switching of the converter; the first target switch and the second target switch are respectively a switch on the matrix circuit and a switch on the full bridge circuit; the driving signal corresponding to the modulation ratio is used to control the switch on or off of each switch on the matrix circuit, and the driving signal corresponding to the shift ratio is used to control the switch on or off of each switch on the full bridge circuit.

[0013] A third aspect of this application provides a soft-switching control system, including: a converter and a controller, electrically connected. The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer via the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect to three-phase AC power. The matrix circuit is equipped with multiple switching transistors. The controller is used to implement the steps in the soft-switching control method for the converter provided in the first aspect of this application.

[0014] The fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a controller, it implements the steps of the soft-switching control method for the converter provided in the first aspect of this application.

[0015] As can be seen from the above, according to the soft-switching control method, device, system, and readable storage medium of the converter provided in this application, after the matrix circuit is connected to three-phase AC power, the first modulation parameters of the converter are calculated based on the output voltage of the converter, and multiple first target drive signals are generated based on the first modulation parameters. Each first target drive signal is used to control the corresponding first target switch to turn on or off, thereby realizing closed-loop control of the converter's output voltage and input current. Based on the first modulation parameters, the second modulation parameters of the converter after closed-loop control are calculated. The first and second modulation parameters are, respectively, a modulation ratio and a shift ratio. Multiple second target drive signals are generated based on the second modulation parameters. Each second target drive signal is used to control the corresponding second target switch to turn on or off, thereby realizing soft switching of the converter. The first and second target switches are, respectively, switches on the matrix circuit and full-bridge circuit. The drive signal corresponding to the modulation ratio is used to control the switches on the matrix circuit to turn on or off, and the drive signal corresponding to the shift ratio is used to control the switches on the full-bridge circuit to turn on or off. By implementing the solution of this application, one modulation parameter in the shift ratio or modulation ratio is first adjusted to achieve closed-loop control of the output voltage and input current; then, another modulation parameter in the shift ratio or modulation ratio is adjusted to drive the corresponding switching transistors to turn on or off at appropriate times, thereby achieving soft switching of all switching transistors across the full voltage range and full load range, which can improve the working efficiency of the converter and achieve the effects of reducing switching losses and improving EMI. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a converter provided in the first embodiment of this application;

[0017] Figure 2 A basic flowchart illustrating a soft-switching control method for a converter provided in the second embodiment of this application;

[0018] Figure 3 A spatial vector distribution map of 6 sectors is provided in the second embodiment of this application;

[0019] Figure 4 This is a schematic diagram illustrating the function of the outer shift ratio and the inner shift ratio in a dual-phase shift mode, provided in the second embodiment of this application.

[0020] Figure 5 This is a schematic diagram illustrating the function of the phase shifting phase in a single-phase shifting mode, provided in the second embodiment of this application.

[0021] Figure 6 This is a schematic diagram illustrating the polarity requirement of the inductor current when implementing soft switching in the dual-phase-shift mode in the second embodiment of this application.

[0022] Figure 7 This is a schematic diagram illustrating the polarity requirement of the inductor current when implementing soft switching in single-phase-shift mode in the second embodiment of this application.

[0023] Figure 8 This is a control block diagram for implementing soft switching when the output voltage is closed-loop controlled by adjusting the modulation ratio in the second embodiment of this application.

[0024] Figure 9 This is a control block diagram for implementing soft switching when the output voltage is closed-loop controlled by adjusting the shift ratio in the second embodiment of this application.

[0025] Figure 10 A waveform diagram of inductor current variation provided for the second embodiment of this application;

[0026] Figure 11 A spatial vector distribution map of 12 sectors is provided in the second embodiment of this application;

[0027] Figure 12 A graph showing the variation of a second modulation parameter with phase shift angle, provided for a second embodiment of this application;

[0028] Figure 13 A schematic diagram illustrating a current limiting condition for implementing soft switching, provided for a second embodiment of this application;

[0029] Figure 14 A schematic diagram of the switching state of a converter at time t0, provided for the second embodiment of this application;

[0030] Figure 15 A graph showing another second modulation parameter as a function of phase shift angle, provided for a second embodiment of this application;

[0031] Figure 16 This is a control block diagram for a soft switch implementation provided in the third embodiment of this application;

[0032] Figure 17 A waveform diagram of inductor current variation provided in the third embodiment of this application;

[0033] Figure 18 This is a control block diagram for a soft switch implementation provided in the fourth embodiment of this application;

[0034] Figure 19 A waveform diagram of inductor current variation provided in the fourth embodiment of this application;

[0035] Figure 20 This is a schematic diagram of the program module of the soft-switching control device for the converter provided in the fifth embodiment of this application. Detailed Implementation

[0036] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] In the description of the embodiments of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0040] To address the problems of difficulty in implementing soft-switching control of converters and the ease with which electromagnetic interference is generated in related technologies, the first embodiment of this application provides a soft-switching control system, including a converter and a controller. The converter and the controller are electrically connected, and the controller is used to implement the soft-switching control method of the converter.

[0041] Specifically, the converter in this embodiment can be a matrix-dual active bridge AC / DC converter. The matrix-dual active bridge AC / DC converter includes a matrix circuit, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer via an inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect to three-phase AC power. The matrix-dual active bridge AC / DC converter in this embodiment has a simplified circuit structure and a low-impedance current path. The primary-side matrix circuit can efficiently convert the three-phase AC input voltage into a high-frequency AC rectangular wave. Combined with the secondary-side full-bridge circuit, it performs phase-shift control similar to a DC / DC dual active bridge, achieving output voltage regulation and input power factor correction (PFC).

[0042] In some embodiments of this example, the converter includes an LC filter, a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit includes three arms, each arm containing two bidirectional switches connected in series, each bidirectional switch consisting of two anti-parallel series-connected switching transistors. The two ends of each arm of the matrix circuit are connected to the primary side of the isolation transformer via an inductor. The three-phase AC power, after passing through the LC filter, is connected to the midpoints of the three arms of the matrix circuit. The midpoints of the arms of the full-bridge circuit are connected to the secondary side of the isolation transformer. The two ends of the full-bridge circuit are connected to an output capacitor and then to an external load or battery.

[0043] Furthermore, in some implementations of this embodiment, such as Figure 2 As shown, the LC filter includes capacitors and inductors. That is, the converter includes three AC-side inductors, three AC-side capacitors, a matrix circuit, an isolation transformer, a full-bridge circuit, an output capacitor, and a load. The matrix circuit has three bridge arms. One end of each of the three AC-side inductors is connected to a three-phase AC power supply port, and the other end of each of the three AC-side inductors is connected to the midpoint of the three bridge arms of the matrix circuit via the three AC-side capacitors.

[0044] In some embodiments of this example, a switching transistor S is provided in the full-bridge circuit. 13 S 14 S 15 S 16 Switch S 13 The emitter and the switch S 14 The collectors of the transistors are connected as one arm of a bridge, and the midpoint of this arm is connected to one end of the secondary side of the isolation transformer; the switching transistor S 15 The emitter and the switch S 16 The collectors of the transistors are connected as one bridge arm, and the midpoint of this bridge arm is connected to the other end of the secondary side of the isolation transformer; the switching transistor S 13 collector and switch S 15 The collector of the transistor is connected to the positive DC side node of the full-bridge circuit and one end of the output capacitor Co. The switching transistor S 14 The emitter and the switch S 16 The emitter is connected to the negative DC side node of the full-bridge circuit and connected to the other end of the output capacitor Co. The output capacitor Co can also be connected to the load R.

[0045] In some embodiments of this example, the matrix circuit also includes multiple switching transistors S. ap S bp S cp S an S bn S cn Each switching transistor consists of two switching transistors connected together, that is, S ap Including switching transistors S1 and S2, S bp Including switching transistors S5 and S6, S cp Including switching transistors S9 and S 10 S an Including switching transistors S3 and S4, S bn Including switching transistors S7 and S8, S cn Including the switching transistor S 11 and S 12 AC side inductor L a With the switching transistor S ap Connection; AC side inductor L b With the switching transistor S bp Connection; AC side inductor L c With the switching transistor S bp Connection; Switch S ap Connected to one end of the primary winding of the isolation transformer; switch S an Connected to the other end of the primary winding of the isolation transformer; switch S bp Connected to one end of the primary winding of the isolation transformer, the switching transistor S bn Connected to the other end of the primary winding of the isolation transformer; switch Scp Connected to one end of the primary winding of the isolation transformer, the switching transistor S cn It is connected to the other end of the primary side of the isolation transformer.

[0046] The second embodiment of this application provides a soft-switching control method for a converter, used to implement soft-switching control of the converter in the first embodiment described above, such as... Figure 2 This is a basic flowchart illustrating the soft-switching control method for the converter provided in this embodiment. The soft-switching control method for the converter includes the following steps:

[0047] Step 201: After the matrix circuit is connected to three-phase AC power, calculate the first modulation parameters of the converter based on the output voltage of the converter, and generate multiple first target drive signals based on the first modulation parameters.

[0048] Specifically, the aforementioned output voltage refers to the DC-side output voltage of the full-bridge circuit. Each first target drive signal is used to control the corresponding first target switch to turn on or off, thereby achieving closed-loop control of the converter's output voltage and input current. The first modulation parameter can be either the shift ratio or the modulation ratio. When the first modulation parameter is the shift ratio, the first target switch includes all the switches on the full-bridge circuit; when the first modulation parameter is the modulation ratio, the first target switch includes all the switches on the matrix circuit. In specific implementation, the first modulation parameter can be controlled by a preset loop control strategy, thereby achieving the goal of closed-loop control of the output voltage and input current. The preset loop control strategy can be a PI dual-loop control, dual-loop decoupling + feedforward control, PR dual-loop control, direct power control, etc., and is not limited here.

[0049] For example, in a PI dual-loop control strategy, the control signal can be continuously updated based on error feedback, ultimately optimizing the phase shift angle. A dual-loop decoupling + feedforward control strategy can use a decoupling control algorithm to compensate for the system's non-ideal characteristics, while feedforward control predicts load changes based on the system model. By combining feedforward information with error information, the phase shift angle is ensured to be adjusted promptly and accurately. A PR dual-loop control strategy can periodically detect the harmonic components of the output signal and automatically correct the phase shift angle to optimize output quality. In a direct power control strategy, the active and reactive power outputs are directly controlled, and the phase shift angle is dynamically adjusted based on real-time power monitoring. That is, power errors can be directly fed back, and the phase shift angle can be quickly adjusted to maintain power balance.

[0050] For example, in the PI dual-loop control strategy, the modulation ratio can be changed by adjusting the PI parameters, thereby controlling the output. The dual-loop decoupling + feedforward control strategy adds decoupling and feedforward elements to the PI dual-loop control. The decoupling element eliminates the mutual influence between the current loop and the voltage loop, while the feedforward element predicts system disturbances and compensates for them in advance. In other words, by optimizing the decoupling and feedforward parameters, the accuracy of the modulation ratio and dynamic response are improved. In the PR dual-loop control strategy, a proportional-resonant (PR) regulator is used to simultaneously regulate current and voltage. The PR regulator has good band-limiting characteristics, which can effectively suppress harmonic interference and improve system stability. That is, by adjusting the PR parameters, the modulation ratio can be changed, improving the quality of the modulated waveform. In the direct power control strategy, the active and reactive power of the output are directly controlled without current and voltage loops. By calculating the power error, the modulation ratio is directly determined, achieving fast and accurate power control.

[0051] Step 202: Based on the first modulation parameters, calculate the second modulation parameters of the converter after closed-loop control.

[0052] Specifically, the first modulation parameter and the second modulation parameter are the modulation ratio and the phase shift angle, respectively. This embodiment can fully utilize the two control degrees of freedom (modulation ratio and phase shift angle). By adaptively adjusting both, soft switching of each switch can be achieved across the entire voltage range and the entire load range.

[0053] Step 203: Generate multiple second target driving signals based on the second modulation parameters.

[0054] Specifically, each second target drive signal is used to control the corresponding second target switch to turn on or off, thereby achieving soft switching of the converter; the first target switch and the second target switch are, respectively, switches on the matrix circuit and the full-bridge circuit; the drive signal corresponding to the modulation ratio is used to control the switching of each switch on the matrix circuit, and the drive signal corresponding to the shift ratio is used to control the switching of each switch on the full-bridge circuit. Through the implementation of this embodiment, when the voltage changes alternately, the target drive signals can be used to drive the corresponding switches to turn on and off in a timely manner, allowing them to switch in a zero-current or zero-voltage state. This can significantly reduce the losses of each switch in the converter during the switching process and improve the overall operating efficiency of the converter.

[0055] In some embodiments of this example, the shift ratio includes an outer shift ratio and an inner shift ratio; correspondingly, the step of calculating the second modulation parameter of the matrix circuit in the converter after closed-loop control based on the first modulation parameter includes: substituting the first modulation parameter into the target calculation formula to calculate the second modulation parameter of the matrix circuit; wherein, the target calculation formula includes a dual-phase-shift mode calculation formula and a single-phase-shift mode calculation formula; the dual-phase-shift mode calculation formula is expressed as:

[0056] U m M+K1D1U o +K2D2U o +K3U o =K4

[0057] The calculation formula for single-phase shift mode is expressed as follows:

[0058] U m M+(K1+K2)D1U o +(K2+K3)U o =K4

[0059] D1 represents the outward shift comparison, D2 represents the inward shift comparison, K1, K2, K3, and K4 are preset constant values, and U o Indicates the output voltage, M represents the modulation ratio, and U represents the modulation ratio. m This indicates the peak value of the three-phase AC phase voltage.

[0060] Specifically, this embodiment provides a coordinated control scheme for the modulation ratio M and the primary-secondary side shift ratios (outer shift ratio D1 and inner shift ratio D2) to achieve soft switching of all switching transistors in the matrix-dual active bridge converter, thereby improving the converter's efficiency and lifespan. The primary-side matrix circuit is responsible for converting the three-phase power frequency input into a volt-second balanced high-frequency AC square wave, which is then sent to the isolation transformer. The matrix circuit has six effective vectors and three zero vectors, and the distribution of the effective vectors is as follows: Figure 3 As shown. The modulation ratio of the matrix circuit is defined as the reference vector magnitude |I|. ref |With effective vector magnitude|I AC |ratio If the multiple is denoted by M, then:

[0061]

[0062] like Figure 4 As shown, when the converter operates in dual-phase shift mode, it has two shift ratios, D1 and D2. The outer shift ratio is defined as D1 = φ1 / π, and the inner shift ratio is defined as D2 = φ2 / π, where φ1 is the secondary arm voltage v. S The rising edge and the output voltage v of the matrix circuit PN The phase shift angle at the rising edge; φ2 is the secondary arm voltage v. S The falling edge and the output voltage v of the matrix circuit PN The magnitude of the phase shift angle at the rising edge.

[0063] like Figure 5 As shown, when D2 = 1 + D1, the converter simplifies from a two-phase-shift mode to a single-phase-shift mode. Hard switching of the switching transistors increases converter losses and heat generation, and also generates significant electromagnetic interference.

[0064] The polarity requirement of the inductor current varies depending on the timing of soft switching. In some implementations of this embodiment, such as... Figure 6 As shown, when the reference vector I ref When the angle between the inductor current and the α-axis in the effective vector distribution diagram is in the interval [-π / 6, 0], due to the symmetry of the three-phase AC, the inductor current easily satisfies the soft-switching condition for t1, t2, t3, t4, t6, t7, t8, and t9, and ZVS (zero voltage switching) is not lost. However, whether ZVS can be achieved for the switching transistors turned on at time t0 and t5 depends on the initial value of the inductor current, i. L The polarity of (t0). When the magnitudes of the phase shift ratio and modulation ratio satisfy the dual-phase shift mode calculation formula, i L The polarity of (t0) is negative, enabling soft switching of all switches in the matrix-dual active bridge converter. In some embodiments of this example, when D2 = 1 + D1, the converter is simplified from a dual-phase-shift mode to a single-phase-shift mode, and when the reference vector I... ref When the angle between the inductor current and the α-axis in the effective vector distribution diagram is in the interval [-π / 6, 0], the polarity of the inductor current satisfies... Figure 7 The conditions shown enable soft switching. When the relationship between the modulation ratio and the phase shift ratio satisfies the single-phase-shift mode calculation formula described above, the return power during the switching cycle can be suppressed to the rated power P. o It is K times that of soft switching.

[0065] In some embodiments of this example, the initial value of the inductor current can be constrained within -40A to -0.1A, and the constant values ​​K1 and K can be constrained in the manner shown in Table 1. S K3 and K4 can be constrained using the method shown in Table 2. By optimizing the selection of the above parameter values, soft switching of all switching transistors can be achieved without bringing high return current power.

[0066] Table 1:

[0067] parameter Range of values <![CDATA[K1]]> [0,20] <![CDATA[K2]]> [-20,20] <![CDATA[K3]]> [-40,0] <![CDATA[K4]]> [0,100]

[0068] Table 2:

[0069] parameter Range of values <![CDATA[Phase shift ratio D1]]> [0,0.8] <![CDATA[Phase shift ratio D2]]> [0,1.8] Modulation ratio M [0,1]

[0070] In some implementations of this embodiment, such as Figure 8 As shown, closed-loop control of the output voltage can be achieved by controlling the modulation ratio, and the corresponding shift ratio can be calculated according to the above target calculation formula. Specifically, the sampled three-phase input voltage and current and output voltage are sent to the closed-loop controller to calculate the modulation ratio M and reactive power control quantity u.q M and u q After dq / αβ coordinate transformation, the control quantity u in the αβ coordinate system is obtained. α and u β The vector modulator generates drive signals V for the first to twelfth switches accordingly. GS_1 ~V GS_12 Used to control the first to twelfth switches S1 to S2 of the matrix circuit. 12 The switching on and off of the transistors achieves output voltage control and input power factor control. The phase shift ratios D1 and D2 are calculated based on the aforementioned target calculation formula and vary linearly with the modulation ratio M. The phase shift controller generates drive signals V for the thirteenth to sixteenth switching transistors based on the phase shift ratios D1 and D2. GS_13 ~V GS_16 Used to control the thirteenth to sixteenth switching transistors S in the full-bridge circuit 13 ~S 16 It can turn on and off to achieve the effect of soft switching.

[0071] In other embodiments of this example, such as Figure 9 As shown, closed-loop control of the output voltage can be achieved by controlling the phase shift ratio, and the corresponding modulation ratio can be calculated according to the above target calculation formula. Specifically, the sampled output voltage is sent to the closed-loop controller to perform transformation control on the output voltage, and the phase shift ratios D1 and D2 are calculated. The phase shift controller generates the drive signals V for the thirteenth to sixteenth switches based on the phase shift ratios D1 and D2. GS_13 ~V GS_16 This is used to control the on / off state of switches thirteen through sixteen in the full-bridge circuit. Simultaneously, the modulation ratio M is calculated using the aforementioned target formula and varies with the shift ratios D1 and D2. The modulation ratio M and the reactive power control quantity u... q (U is taken when unity power factor control is achieved) q =0) After the dq / αβ coordinate transformation, the control quantity u in the αβ coordinate system is obtained. α and u β The vector modulator generates drive signals V for the first to twelfth switches accordingly. GS_1 ~V GS_12 Used to control the first to twelfth switches S1 to S2 of the matrix circuit. 12 The modulation ratio M and the shift ratio D1 and D2 satisfy the relationship defined by the above target calculation formula, which can achieve the control effect of soft switching.

[0072] Using the above Figure 8 When the control converter is turned on to operate in the manner shown in Figure 9, for any given set of parameters (L = 10uH, n = 1, U...), o =500V, f sThe waveform of inductor current change at 70kHz, K1=0.667, K2=0.667, K3=-1.333, K4=18.667 (e.g.) Figure 10 As shown in the figure, it can be seen that under different loads, the initial value of the inductor current can always be precisely controlled at the desired -10A, which helps to achieve soft switching of all switching transistors in the full range and improve the efficiency of the converter.

[0073] In one embodiment of this example, before the step of calculating the second modulation parameters of the matrix circuit in the converter after closed-loop control based on the first modulation parameters, the method further includes: generating a spatial vector diagram of the converter based on the current vectors corresponding to different operating modes of the matrix circuit and the phase voltage values ​​in the three-phase AC power; wherein, the spatial vector diagram includes multiple sectors, each sector in the time domain corresponds to multiple switching cycles, and each switching cycle corresponds to multiple operating modes; based on the symmetrical distribution rules of the vector current in the sectors of the spatial vector diagram, combined with the vector duty cycle of the target sector in the spatial vector diagram and the phase voltage values ​​in the three-phase AC power, the target calculation formula is derived.

[0074] Specifically, the matrix circuit can convert the three-phase power frequency input into a volt-second balanced high-frequency AC square wave and send it to the primary side of the isolation transformer. To ensure the normal operation of the circuit, short circuits are not allowed at its input and open circuits are not allowed at its output. Nine current vectors can be set, as shown in Table 1. The on / off state of the switch corresponding to each vector is represented by 1 / 0, and one current vector corresponds to one operating mode.

[0075] Table 1:

[0076]

[0077]

[0078] Based on the magnitudes of adjacent vectors and the phase voltage values ​​in the three-phase AC current, a spatial vector diagram of the converter is constructed, and the spatial vector diagram is divided into 12 small sectors, such as... Figure 11 As shown in Table 2, the vector selection within each small sector and the corresponding vector duty cycle are shown in Table 2, where D R D represents the duty cycle of the effective vector to the right of the reference vector. L D0 represents the duty cycle of the effective vector to the left of the reference vector, and D0 represents the duty cycle of the zero-effective vector. M is the modulation ratio of the matrix circuit.

[0079] Table 2:

[0080]

[0081] Based on the spatial vector diagram, the duty cycle of the aforementioned current vector, and the symmetry characteristics of the sector current vector, a quantitative analysis of the converter's operating modes can be performed, leading to the derivation of the control expression for achieving soft switching, which is also the aforementioned target calculation formula.

[0082] Taking sector 1 as an example, that is, determining the first sector as the target sector, we can perform a quantitative analysis of the converter's operating modes:

[0083] Definition of shift compared to: D φ1 =φ1 / π, where φ1 represents the phase shift angle of the primary and secondary sides.

[0084] First working mode (t0-t1): Original edge S ap and S bn When the circuit is turned on, the output voltage of the matrix circuit is the line voltage u. AB Secondary side S 14 and S 15 When the circuit is turned on, the voltage refracted to the primary side is -nU. o Where n represents the primary-to-secondary turns ratio of the transformer, i.e., the ratio of the primary turns to the secondary turns, U o This represents the output voltage of the converter. The voltage across the inductor L is u. AB +nU o The inductor current increases linearly. At the moment when the inductor current crosses zero (t... zc Before a certain point in time (t), energy is transferred from the inductor to the primary power source and the secondary load. zc After a certain time, the primary power supply and secondary load store energy in the inductor. The expression for the inductor current during this stage is:

[0085]

[0086] The inductor current at the end of the mode is:

[0087]

[0088] Second working mode: Primary edge S ap and S bn When the circuit is turned on, the output voltage of the matrix circuit is the line voltage u. AB Secondary side S 13 and S 16 When the circuit is turned on, the voltage refracted to the primary side is nU. o The voltage across inductor L is u AB -nU o Whether the inductor current rises or falls depends on the sign of the voltage across its terminals. During this stage, the primary power supply transfers energy to the secondary load. The expression for the inductor current during this stage is:

[0089]

[0090] The inductor current at the end of the mode is:

[0091]

[0092] Third working mode: Primary edge S ap and S cn When the circuit is turned on, the output voltage of the matrix circuit is the line voltage u. AC Secondary side S 13 and S 16 When the circuit is turned on, the voltage refracted to the primary side is nU. o The voltage across inductor L is u AC -nU o Whether the inductor current rises or falls depends on the sign of the voltage across its terminals. During this stage, the primary power supply transfers energy to the secondary load. The expression for the inductor current during this stage is:

[0093]

[0094] The inductor current at the end of the mode is:

[0095]

[0096] Fourth working mode: primary side S ap and S an When the circuit is turned on, the output voltage of the matrix circuit is 0, and the secondary side S... 13 and S 16 When the circuit is turned on, the voltage refracted to the primary side is nU. o The voltage across inductor L is -nU o The inductor current decreases linearly as the inductor transfers energy to the secondary load. The expression for the inductor current during this stage is:

[0097]

[0098] The inductor current at the end of the mode is:

[0099]

[0100] The operating modes in the second half of the switching cycle are symmetrical to those in the first half of the switching cycles, and will not be elaborated here.

[0101] Due to the current symmetry of a single switching cycle, i L (t4)=-i L (t0), that is:

[0102]

[0103] Simplifying, we can obtain the initial value i of the inductor current in sector 1. L The expression for (t0) is:

[0104]

[0105] The three-phase input line voltage U ab and U ac The expression is:

[0106]

[0107]

[0108] Where w is the angular frequency of the AC input voltage, and pi is pi (π).

[0109] D in Table 2 R =M*sin(π / 6-ωt) and D L =M*sin(π / 6+ωt) Substitute into D ab and D ac In the above, combined with the three-phase input line voltage U ab and U ac The expression for the initial value of the inductor current can be further simplified to:

[0110]

[0111] Based on this, the corresponding relationship between the modulation ratio M and the phase shift angle φ1 in single-phase shift mode can be derived as Equation 1 (that is, the expansion of the above single-phase shift mode calculation formula):

[0112]

[0113] Among them, f s f represents the switching frequency. s =1 / T s .

[0114] Therefore, while controlling the output voltage through the modulation ratio M, to achieve a fixed negative current control in each switching cycle, an initial inductor current value i can be set. L Substituting (t0) into the above formula, the phase shift angle φ1 changes linearly with the modulation ratio M, achieving precise control of the initial current value. A curve showing the change in phase shift angle and modulation ratio can be plotted, such as... Figure 12 As shown, the initial value of the fixed current i L At time (t0), there is a linear relationship between the phase shift angle φ1 and the modulation ratio M.

[0115] By reasonably limiting the current polarity and current amplitude of each switching transistor, soft switching can be achieved for all switching transistors across the entire voltage range (e.g., 300V~1000V) and the entire load range (e.g., 0~40kW); the limiting conditions can be set according to... Figure 13 Configure as shown in Table 3:

[0116] Table 3:

[0117]

[0118]

[0119] It should be understood that in the relevant technical solutions, because only power output requirements are considered, there are no constraints on the inductor current waveform. This causes some switches in the matrix circuit to lose the ZVS (zero-voltage switching) condition, resulting in significant conduction losses. This is especially true when the input and output voltages are mismatched, making the ZVS loss even more severe. This will introduce additional switching losses to the hard switching of the switches, reducing the converter's conversion efficiency; it will also lead to greater noise, adversely affecting the overall EMI level of the device.

[0120] Furthermore, in one embodiment of this invention, the initial value of the inductor current and the output voltage of the matrix circuit satisfy the following relationship:

[0121]

[0122] Where u represents the voltage value output by the matrix circuit at the corresponding time, and t dead c represents the dead time. 0_mosfet This represents the equivalent capacitance of the target switching transistor.

[0123] Specifically, the initial value of the inductor current has a significant impact on the implementation of soft switching, such as... Figure 14 As shown, taking time t0 of sector 1 as an example, the inductor current condition for the switch to achieve ZVS turn-on is explained. At time t0, the previous cycle ends, and S... an Shutdown, S bn Not yet connected, at this time S bn With voltage positive at the bottom and negative at the top, to achieve ZVS turn-on, an inductor current i is required. L In dead time t dead S cn The charge on it is discharged, and at the same time, it is given to S. an Charge to u AB The required inductor current i L The polarity must be negative, and the absolute value of the inductor current must satisfy:

[0124]

[0125] Initial value of negative inductor current i L (t0) If the polarity is set to negative and the absolute value is too large, the return current power will increase, which will negatively impact efficiency. To achieve soft switching of all switching transistors without introducing additional return current power, in some specific implementations, the initial value of the inductor current can be set to:

[0126]

[0127] Substituting the initial value of the inductor current into Equation 1, which describes the relationship between the modulation ratio M and the phase angle φ1 in single-phase-shift mode, we can derive Equation 2, which describes a more specific relationship between the phase angle φ1 and the modulation ratio M:

[0128]

[0129] Based on this, for any given set of parameters (L=15uH, n=1, U o =500V, f s =70kHz i L Under (t0)=-10A), the curve of modulation ratio M as a function of phase shift angle φ1 can be obtained as follows: Figure 15 As shown. Closed-loop control of the converter's output voltage is achieved through phase-shift control, resulting in output voltage stabilization. The modulation ratio M is obtained from the above formula, allowing the modulation ratio M to adjust with the phase shift ratio D. φ1 Linear variation achieves the control effect of soft switching.

[0130] Therefore, through the implementation of this embodiment, after the matrix circuit is connected to three-phase AC power, the first modulation parameters of the converter are calculated based on the output voltage of the converter, and multiple first target drive signals are generated based on the first modulation parameters. Each first target drive signal is used to control the corresponding first target switch to turn on or off, realizing closed-loop control of the converter's output voltage and input current. Based on the first modulation parameters, the second modulation parameters of the converter after closed-loop control are calculated. The first and second modulation parameters are, respectively, a modulation ratio and a shift ratio. Multiple second target drive signals are generated based on the second modulation parameters. Each second target drive signal is used to control the corresponding second target switch to turn on or off, realizing soft switching of the converter. The first and second target switches are, respectively, switches on the matrix circuit and full-bridge circuit. The drive signal corresponding to the modulation ratio is used to control the switches on the matrix circuit to turn on or off, and the drive signal corresponding to the shift ratio is used to control the switches on the full-bridge circuit to turn on or off. By implementing the solution of this application, one modulation parameter in the shift ratio or modulation ratio is first adjusted to achieve closed-loop control of the output voltage and input current; then, another modulation parameter in the shift ratio or modulation ratio is adjusted to drive the corresponding switching transistors to turn on or off at appropriate times, thereby achieving soft switching of all switching transistors across the full voltage range and full load range, which can improve the working efficiency of the converter and achieve the effects of reducing switching losses and improving EMI.

[0131] The third embodiment of this application provides a specific control method for soft switching of a converter, using the shift ratio as the first modulation parameter and the modulation ratio as the second modulation parameter to control the converter and achieve soft switching of each switching transistor across the entire voltage range; specifically, it includes the following implementation methods:

[0132] In one embodiment of this example, after the matrix circuit is connected to three-phase AC power, the step of calculating the first modulation parameter of the converter based on the output voltage of the converter includes: after the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be a shift ratio, calculating the first error parameter between the output voltage of the converter and a preset output voltage reference value; inputting the first error parameter to a preset voltage loop PI regulator to output the shift ratio through the voltage loop PI regulator.

[0133] Specifically, after the matrix circuit is connected to three-phase AC power, a first error parameter between the output voltage and the preset output voltage reference value is calculated; the first error parameter is input to a preset voltage loop PI regulator so that the shift ratio of the converter is output through the voltage loop PI regulator; based on the shift ratio, the output voltage of the converter is controlled in a closed loop.

[0134] Furthermore, in one embodiment of this example, the step of performing closed-loop control of the converter's output voltage based on the phase shift ratio includes: determining the target transfer energy from the primary side to the secondary side of the converter based on the phase shift ratio; generating a phase shift control signal for the converter based on the target transfer energy; wherein the phase shift control signal is used to regulate the phase difference between the primary side and the secondary side to achieve closed-loop control of the converter's output voltage.

[0135] Specifically, such as Figure 16 The diagram shows a control block diagram for soft switching in one specific implementation. To satisfy the closed-loop control of the output voltage, a mathematical model corresponding to the converter can be constructed based on a PI dual-loop control strategy, forming an outer voltage loop and an inner current loop. The outer voltage loop controls the DC-side voltage of the converter, and the inner current loop controls the current according to the parameters output by the outer voltage loop.

[0136] The voltage outer loop is composed of U o_ref U o And the PI (Protein Injection) stage. U o_ref U is the output voltage reference value. o The output voltage of the converter is represented by PI, which indicates a voltage loop PI regulator, also known as a proportional-integral regulator. The output voltage reference value U is... o_ref With output voltage U o The difference obtained by subtraction (i.e., the first error parameter mentioned above) is fed into the voltage loop PI regulator, and the output shift ratio of the voltage loop PI regulator is D. φ1Furthermore, the output voltage U can be controlled via a voltage loop PI regulator. o Real-time follow reference value U o_ref This achieves the goal of closed-loop control of the output voltage. Specifically, during the closed-loop control process, when the output voltage is too low, U... o_ref and U o When the difference is positive, the output of the voltage loop PI regulator increases, shifting the ratio D. φ1 As the voltage increases, more energy is transferred from the primary side to the secondary side, resulting in a higher output voltage and achieving a closed-loop effect.

[0137] In one embodiment of this example, the step of calculating the modulation ratio of the matrix circuit in the converter after closed-loop control based on the phase shift ratio includes: substituting the phase shift ratio into the single-phase-shift mode calculation formula to calculate the modulation ratio of the matrix circuit; wherein, the single-phase-shift mode calculation formula is expressed as:

[0138]

[0139] Among them, D φ1 Compared to moving, i L (t0) represents the initial value of the inductor current in the sector to which the converter's current operating mode belongs, L represents the inductance value, and f s U represents the switching frequency. o Indicates the output voltage, n represents the turns ratio of the primary and secondary sides of the isolation transformer, M represents the modulation ratio, and U... m This indicates the peak value of the three-phase AC phase voltage.

[0140] Furthermore, in some specific implementations, the modulation ratio required for soft-switching control can be calculated using the following specific single-phase-shift mode calculation formula, which is expressed as follows:

[0141]

[0142] Among them, t dead C represents the dead time. 0mosfet This represents the equivalent capacitance of the target switching transistor.

[0143] Furthermore, in one embodiment of this example, the step of generating the target drive signal of the matrix circuit based on the modulation ratio includes: determining the modulation ratio as an active control quantity, and inputting the active control quantity and a preset reactive control quantity into a preset dq / αβ transformation model to calculate the vector modulation parameters of the matrix circuit; and generating the target drive signal of the matrix circuit based on the vector modulation parameters.

[0144] Specifically, such as Figure 16 As shown, the modulation ratio M is determined as the active power control quantity, and is matched with the preset reactive power control quantity u. qThis allows for control of the input power factor. To achieve corrective control of the input power factor, the reactive power control quantity u can be... q Setting it to 0 will control the power factor to 1. M and u q Through the dq / αβ transformation model, the coordinate transformation from the two-phase rotating dq coordinate system to the two-phase stationary αβ coordinate system can be realized, and the control quantity u in the two-phase stationary αβ coordinate system can be obtained. α and u β Furthermore, the matrix vector modulator can be combined with u α and u β Calculate the S of each switch in the primary matrix circuit. ap S bp S cp S an S bn S cn Target driving signal V GS_AP V GS_BP V GS_CP V GS_AN V GS_BN V GS_CN .

[0145] Through the implementation of the scheme in this embodiment, for any given set of parameters (L=10uH, n=1, U o =500V, f s =70kHz, i L (t0)=-10A), all can be obtained as follows: Figure 17 The waveform diagram showing the inductor current variation demonstrates that, under different modulation ratios, the initial inductor current can always be precisely controlled at the desired -10A, helping to achieve soft switching of all switching transistors across the entire range and improving converter efficiency. It is important to emphasize that in related technologies, closed-loop control of output voltage regulation and correction of input power factor often require sampling the three-phase input current and placing it into the current loop for control. However, this embodiment does not require sampling the three-phase input current, saving the cost of current sampling chips and peripheral circuitry, and further increasing power density.

[0146] Therefore, through the implementation of this embodiment, after the matrix circuit is connected to three-phase AC power, the phase shift ratio of the converter is calculated based on the converter's output voltage, and closed-loop control of the converter's output voltage is performed. Based on the phase shift ratio, the modulation ratio of the matrix circuit in the converter after closed-loop control is calculated. Based on the modulation ratio, a target drive signal for the matrix circuit is generated. This target drive signal is used to drive the corresponding bidirectional switching transistors to turn on or off during the converter's mode switching process, thereby achieving soft switching of the converter. In this embodiment, closed-loop control of the output voltage is performed by adjusting the phase shift angle. According to the target calculation formula, the corresponding modulation ratio M is calculated, achieving soft switching of all switching transistors across the entire voltage and load range. This helps reduce switching losses, improve converter efficiency, and reduce EMI. Furthermore, the soft-switching control method provided in this embodiment does not require sampling the input current to complete power factor correction, which helps save circuit costs.

[0147] The fourth embodiment of this application also provides a specific control method for soft switching of a converter, using the modulation ratio as the first modulation parameter and the shift ratio as the second modulation parameter to control the converter and realize soft switching of each switching transistor across the entire voltage range; specifically, it includes the following implementation methods:

[0148] In one embodiment of this example, the step of calculating the first modulation parameter of the converter based on the output voltage of the converter after the matrix circuit is connected to three-phase AC power includes: after the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be the modulation ratio, calculating the second error parameter between the output voltage of the converter and the preset output voltage reference value, and determining the current active component reference value of the matrix circuit based on the second error parameter; combining the three-phase current sampling value of the converter and the current active component reference value, performing input power factor correction on the matrix circuit, and outputting the modulation ratio.

[0149] Specifically, after the matrix circuit is connected to three-phase AC power, a second error parameter between the output voltage and the preset output voltage reference value is calculated, and the active current component reference value of the matrix circuit is determined based on the second error parameter. Combining the three-phase current sampling value and the active current component reference value, the input power factor of the matrix circuit is corrected to obtain the corresponding reactive power control quantity and modulation ratio. Based on the reactive power control quantity and modulation ratio, a first drive signal for the matrix circuit is generated. The first drive signal is used to drive the corresponding second switch to turn on or off, so as to realize closed-loop control of the converter output voltage and input current.

[0150] Furthermore, in one embodiment of this example, the step of combining the three-phase current sampling values ​​and the active current component reference values ​​to perform input power factor correction on the matrix circuit and obtain the corresponding reactive control quantity and modulation ratio includes: inputting the three-phase current sampling values ​​into a preset abc / dq conversion model to calculate the reactive current and active current corresponding to the three-phase current sampling values; generating power factor correction parameters by combining the reactive current and the preset reactive current component reference values; inputting the power factor correction parameters into the reactive current PI regulator of the converter to realize input power factor correction of the matrix circuit and output the corresponding reactive control quantity; and inputting the active current component reference values ​​and the active current into the active current PI regulator of the converter so that the active current PI regulator outputs the modulation ratio of the matrix circuit.

[0151] Furthermore, in one embodiment of this example, the step of generating the first drive signal of the matrix circuit based on the reactive power control quantity and the modulation ratio includes: inputting the reactive power control quantity and the modulation ratio into a preset dq / αβ transformation model, calculating the vector modulation parameters of the matrix circuit, and generating the first drive signal of the matrix circuit based on the vector modulation parameters.

[0152] Specifically, such as Figure 18 The diagram shows a control block diagram for soft switching in one specific implementation. To satisfy closed-loop control of the output voltage and power factor correction control of the input current, a mathematical model corresponding to the converter is constructed based on a PI dual-loop control strategy, forming an outer voltage loop and an inner current loop. The outer voltage loop controls the DC-side voltage of the converter, and the inner current loop controls the current according to the parameters output by the outer voltage loop.

[0153] The voltage outer loop is composed of U o_ref U o And the PI (Protein Injection) stage. U o_ref U is the output voltage reference value. o The output voltage of the converter is represented by PI, indicating a voltage loop PI regulator. The output voltage reference value U is... o_ref With output voltage U o The difference obtained by subtraction (i.e., the second error parameter mentioned above) is fed into the voltage loop PI regulator; the voltage loop PI regulator controls the output voltage U. o Real-time follow reference value U o_ref This achieves the goal of closed-loop control of the output voltage, and uses the output of the voltage loop PI regulator as the reference value i for the active current component in the two-phase rotating dq coordinate system. dref .

[0154] The inner current loop is composed of i abc abc / dq, i d i q u d_PI uq_PI It consists of two PI stages. abc The sampled values ​​of the three-phase input current (i.e., the three-phase current sampled values ​​mentioned above) are represented by the abc / dq transformation model, which can realize the coordinate transformation from the three-phase stationary abc coordinate system to the two-phase rotating dq coordinate system. d and i q i abc The output active and reactive currents after abc / dq coordinate transformation. The reference value i of the active component of the current in the two-phase rotating dq coordinate system. dref With active current i d The difference is fed into the active current PI regulator, which outputs the modulation ratio M. The current loop PI regulator controls the input active current to follow the reference value i in real time. dref To achieve power factor correction and ensure that the input voltage and input current are in phase, ideally there should be no reactive current. Therefore, the reactive current reference value can be set to 0, and 0 should be related to the reactive current i. q The difference between the two values ​​is fed into the reactive current PI regulator, which controls the reactive current to be zero. The active current PI regulator outputs the modulation ratio M, and the reactive current PI regulator outputs the reactive control quantity u. q M and u q The dq / αβ transformation model can realize the coordinate transformation from the two-phase rotating dq coordinate system to the two-phase stationary αβ coordinate system, and obtain the vector modulation parameter u in the two-phase stationary αβ coordinate system. α and u β . will u α and u β The input is fed into a matrix vector modulator, which can then calculate the S values ​​of each bidirectional switch in the primary-side matrix circuit. ap S bp S cp S an S bn S cn The first driving signal V GS_AP V GS_BP V GS_CP V GS_AN V GS_BN V GS_CN .

[0155] Furthermore, in some embodiments of this example, given the completion of the aforementioned voltage outer loop + current inner loop, the modulation ratio M calculated by the active current PI regulator is substituted into the target calculation formula to calculate the shift ratio D. φ1 The size of the phase shifter, and thus, the phase shifter can shift the phase relative to D. φ1Calculate the second drive signal V corresponding to each of the first switching transistors S1, S2, S3, and S4 in the full-bridge circuit. GS_1 V GS_2 V GS_3 V GS_4 In some specific drive control schemes, that is, in the process of driving and controlling the corresponding first switching transistor through the second drive signal, V can be made... GS_1 V GS_4 With both signals on and off simultaneously, and ignoring dead time, the duty cycle is 50%. In terms of phase, the rising edge of the second drive signal differs from the rising edge of the first vector of the primary matrix circuit by D. φ1 T s V GS_2 V GS_3 When both switches are on and off simultaneously, ignoring dead zones, the duty cycle is 50%, and it is the same as V. GS_1 V GS_4 Complementary. Based on this drive control scheme, any set of parameters (L=15uH, n=1, U) can be obtained. o =500V, f s =70kHz, i L The waveform of the inductor current change under (t0)=-10A is shown in the figure. Figure 19 As shown, the initial value of the inductor current can always be precisely controlled at the desired -10A under different modulation ratios. That is, it can help achieve soft switching of all switching transistors in the full voltage range and full load range, thereby improving the efficiency of the converter.

[0156] Therefore, through the implementation of this embodiment, after the matrix circuit is connected to three-phase AC power, the modulation ratio of the matrix circuit is calculated based on the output voltage and three-phase current sampling values ​​of the converter, and the output voltage of the converter is subjected to closed-loop control. Based on the modulation ratio, the phase shift ratio of the converter after closed-loop control is calculated. Based on the phase shift ratio, a second drive signal for the full-bridge circuit is generated. The second drive signal is used to drive the corresponding first switch to turn on or off during the switching of the converter's operating mode, thereby realizing the soft switching of the converter. Specifically, this embodiment takes output voltage control and input power factor correction control as the first control objective, and realizes soft switching of all switches in the full voltage range and full load range as the second control objective, making full use of the control degrees of freedom (modulation ratio M and phase shift angle φ1) in the converter. The output voltage is controlled in a closed loop by adjusting the modulation ratio M. The corresponding phase shift angle φ1 is calculated according to the target calculation formula, which can realize soft switching of all switches in the full voltage range and full load range, thereby reducing switching losses, improving converter efficiency, and improving EMI.

[0157] Figure 20This application provides a soft-switching control device for a converter according to a fifth embodiment. The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer via the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. Both the matrix circuit and the full-bridge circuit are equipped with multiple switching transistors. Figure 10 As shown, the soft-switching control device of the converter mainly includes:

[0158] The first calculation module 2001 is used to calculate the first modulation parameters of the converter based on the output voltage of the converter after the matrix circuit is connected to three-phase AC power, and to generate multiple first target drive signals based on the first modulation parameters; wherein, each first target drive signal is used to control the corresponding first target switch to be turned on or off, so as to realize closed-loop control of the output voltage and input current of the converter.

[0159] The second calculation module 2002 is used to calculate the second modulation parameters of the converter after closed-loop control based on the first modulation parameters; wherein, the first modulation parameter and the second modulation parameter are, respectively, the modulation ratio and the shift ratio.

[0160] The generation module 2003 is used to generate multiple second target driving signals based on the second modulation parameters; wherein, each second target driving signal is used to control the corresponding second target switch to turn on or off, so as to realize the soft switching of the converter; the first target switch and the second target switch are, respectively, a switch on the matrix circuit and a switch on the full-bridge circuit; the driving signal corresponding to the modulation ratio is used to control the switch on or off of each switch on the matrix circuit, and the driving signal corresponding to the shift ratio is used to control the switch on or off of each switch on the full-bridge circuit.

[0161] In some embodiments of this example, the first calculation module is specifically used to: calculate a first error parameter between the output voltage of the converter and a preset output voltage reference value after the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be the shift ratio; input the first error parameter to a preset voltage loop PI regulator so as to output the shift ratio through the voltage loop PI regulator.

[0162] In some embodiments of this example, the first calculation module is further specifically used to: after the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be the modulation ratio, calculate the second error parameter between the output voltage of the converter and the preset output voltage reference value, and determine the current active component reference value of the matrix circuit based on the second error parameter; combine the three-phase current sampling value of the converter and the current active component reference value to perform input power factor correction on the matrix circuit and output modulation ratio.

[0163] In some embodiments of this example, the phase shift ratio includes an outer phase shift ratio and an inner phase shift ratio; correspondingly, the second calculation module is specifically used to: substitute the first modulation parameter into the target calculation formula to calculate the second modulation parameter of the matrix circuit; wherein, the target calculation formula includes a dual-phase-shift mode calculation formula and a single-phase-shift mode calculation formula; the dual-phase-shift mode calculation formula is expressed as:

[0164] U m M+K1D1U o +K2D2U o +K3U o =K4

[0165] The calculation formula for single-phase shift mode is expressed as follows:

[0166] U m M+(K1+K2)D1U o +(K2+K3)U o =K4

[0167] D1 represents the outward shift comparison, D2 represents the inward shift comparison, K1, K2, K3, and K4 are preset constant values, and U o Indicates the output voltage, M represents the modulation ratio, and U represents the output voltage. m This indicates the peak value of the three-phase AC phase voltage.

[0168] In some embodiments of this example, a derivation module is also included. The derivation module is used to: generate a spatial vector diagram of the converter based on the current vectors corresponding to different operating modes of the matrix circuit and the phase voltage values ​​in the three-phase AC power; wherein, the spatial vector diagram includes multiple sectors, each sector in the time domain corresponds to multiple switching cycles, and each switching cycle corresponds to multiple operating modes; based on the symmetrical distribution rules of the vector current in the sector of the spatial vector diagram, combined with the vector duty cycle of the target sector in the spatial vector diagram and the phase voltage values ​​in the three-phase AC power, derive the target calculation formula.

[0169] Furthermore, in some embodiments of this example, the initial value of the inductor current and the output voltage of the matrix circuit satisfy the following relationship:

[0170]

[0171] Where u represents the voltage value output by the matrix circuit at the corresponding time, and t dead C represents the dead time. 0_mosfet This represents the equivalent capacitance of the target switching transistor.

[0172] In some embodiments of this example, the generation module is specifically used to: when the second modulation parameter is the modulation ratio, determine the second modulation parameter as the active control quantity, and input the active control quantity and the preset reactive control quantity into the preset dq / αβ transformation model to calculate the vector modulation parameters of the matrix circuit; based on the vector modulation parameters, generate the second target drive signal for each switch in the matrix circuit.

[0173] According to the soft-switching control device for the converter provided in this embodiment, after the matrix circuit is connected to three-phase AC power, the first modulation parameters of the converter are calculated based on the output voltage of the converter, and multiple first target drive signals are generated based on the first modulation parameters. Each first target drive signal is used to control the corresponding first target switch to turn on or off, thereby achieving closed-loop control of the converter's output voltage and input current. Based on the first modulation parameters, the second modulation parameters of the converter after closed-loop control are calculated. The first and second modulation parameters are, respectively, a modulation ratio and a shift ratio. Based on the second modulation parameters, multiple second target drive signals are generated. Each second target drive signal is used to control the corresponding second target switch to turn on or off, thereby achieving soft switching of the converter. The first and second target switches are, respectively, switches on the matrix circuit and full-bridge circuit. The drive signal corresponding to the modulation ratio is used to control the switches on the matrix circuit to turn on or off, and the drive signal corresponding to the shift ratio is used to control the switches on the full-bridge circuit to turn on or off. By implementing the solution in this application, one modulation parameter in the shift ratio or modulation ratio is first adjusted to achieve closed-loop control of the output voltage and input current; then, another modulation parameter in the shift ratio or modulation ratio is adjusted to drive each corresponding switch to turn on or off at the appropriate time, thereby achieving soft switching of all switches across the full voltage range and full load range, which can improve the working efficiency of the converter and reduce switching losses and improve EMI.

[0174] The sixth embodiment of this application also provides a soft-switching control system. This soft-switching control system can be used to implement the soft-switching control method for the converter in the foregoing embodiments, mainly including: a converter and a controller electrically connected to the converter; the controller can be configured with a memory, a controller, and a computer program stored in the memory and executable on the controller, the memory and the controller being communicatively connected. When the controller executes the computer program, it implements the method in the second embodiment described above. The number of controllers can be one or more.

[0175] The memory can be high-speed random access memory (RAM) or non-volatile memory, such as disk storage. The memory is used to store executable program code, and the controller is coupled to the memory.

[0176] Furthermore, embodiments of this application also provide a computer-readable storage medium, which may be disposed in the aforementioned soft-switching control system, and may be the memory in the foregoing embodiments.

[0177] The computer-readable storage medium stores a computer program that, when executed by the controller, implements the soft-switching control method for the converter in the aforementioned embodiments. Furthermore, the computer-readable storage medium can also be a USB flash drive, external hard drive, read-only memory (ROM), RAM, magnetic disk, or optical disk, or any other medium capable of storing program code.

[0178] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0179] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0180] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0181] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned readable storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0182] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0183] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0184] The above is a description of the soft-switching control method, apparatus, system, and readable storage medium of the converter provided in this application. For those skilled in the art, based on the ideas of the embodiments of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A soft-switching control method for a converter, characterized in that, The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer through the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors; The soft-switching control method includes: After the matrix circuit is connected to three-phase AC power, the first modulation parameters of the converter are calculated based on the output voltage of the converter, and multiple first target drive signals are generated based on the first modulation parameters; wherein, each first target drive signal is used to control the corresponding first target switch to turn on or off, so as to realize closed-loop control of the output voltage and input current of the converter; Based on the first modulation parameter, the second modulation parameter of the converter after closed-loop control is calculated; wherein, the first modulation parameter and the second modulation parameter, one is the modulation ratio and the other is the shift ratio, the shift ratio including the outer shift ratio and the inner shift ratio; the calculation of the second modulation parameter of the matrix circuit in the converter after closed-loop control based on the first modulation parameter includes: Substituting the first modulation parameter into the target calculation formula, the second modulation parameter of the matrix circuit is calculated; wherein, the target calculation formula includes a dual-phase-shift mode calculation formula and a single-phase-shift mode calculation formula; the dual-phase-shift mode calculation formula is expressed as: The calculation formula for the single-phase shift mode is expressed as follows: Compared to the aforementioned outward movement, Compared to the inward shift, , , , These are preset constant values. U o This indicates the output voltage. M This indicates the modulation ratio. U m Indicates the peak value of the three-phase AC phase voltage; Multiple second target drive signals are generated based on the second modulation parameters; wherein each second target drive signal is used to control the corresponding second target switch to turn on or off, so as to realize the soft switching of the converter; the first target switch and the second target switch are respectively the switch on the matrix circuit and the switch on the full bridge circuit; the drive signal corresponding to the modulation ratio is used to control the switch on or off of each of the switches on the matrix circuit, and the drive signal corresponding to the shift ratio is used to control the switch on or off of each of the switches on the full bridge circuit.

2. The soft-switching control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, the calculation of the first modulation parameters of the converter based on the output voltage of the converter includes: After the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be the shift ratio, the first error parameter between the output voltage of the converter and the preset output voltage reference value is calculated. The first error parameter is input to a preset voltage loop PI regulator, so that the shift ratio is output through the voltage loop PI regulator.

3. The soft-switching control method for the converter according to claim 1, characterized in that, After the matrix circuit is connected to three-phase AC power, the calculation of the first modulation parameters of the converter based on the output voltage of the converter includes: After the matrix circuit is connected to three-phase AC power and the first modulation parameter of the converter is determined to be the modulation ratio, the second error parameter between the output voltage of the converter and the preset output voltage reference value is calculated, and the reference value of the active current component of the matrix circuit is determined based on the second error parameter. By combining the three-phase current sampling values ​​of the converter and the reference value of the active current component, the matrix circuit is subjected to input power factor correction, and the modulation ratio is output.

4. The soft-switching control method for the converter according to claim 1, characterized in that, Before calculating the second modulation parameters of the converter after closed-loop control based on the first modulation parameters, the method further includes: Based on the current vectors corresponding to different operating modes of the matrix circuit and the phase voltage values ​​in the three-phase AC power, a spatial vector diagram of the converter is generated; wherein, the spatial vector diagram includes multiple sectors, each sector in the time domain corresponds to multiple switching cycles, and each switching cycle corresponds to multiple operating modes; Based on the symmetrical distribution rules of vector current within the sector of the spatial vector diagram, and combined with the vector duty cycle of the target sector in the spatial vector diagram and the phase voltage values ​​in the three-phase AC power, the target calculation formula is derived.

5. The soft-switching control method for the converter according to claim 1, characterized in that, The initial value of the inductor current and the output voltage of the matrix circuit satisfy the following relationship: in, This represents the voltage value output by the matrix circuit at the corresponding moment. Indicates dead time. This represents the equivalent capacitance of the target switching transistor.

6. The soft-switching control method for the converter according to claim 2, characterized in that, The generation of multiple second target driving signals based on the second modulation parameters includes: When the second modulation parameter is the modulation ratio, the second modulation parameter is determined as the active power control quantity, and the active power control quantity and the preset reactive power control quantity are input to the preset dq / αβ transformation model to calculate the vector modulation parameters of the matrix circuit. Based on the vector modulation parameters, a second target drive signal corresponding to each of the switching transistors in the matrix circuit is generated.

7. A soft-switching control device for a converter, characterized in that, The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer through the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors; The soft-switching control device includes: The first calculation module is used to calculate the first modulation parameters of the converter based on the output voltage of the converter after the matrix circuit is connected to three-phase AC power, and to generate a plurality of first target drive signals based on the first modulation parameters; wherein, each first target drive signal is used to control the corresponding first target switch to be turned on or off, so as to realize closed-loop control of the output voltage and input current of the converter. The second calculation module is used to calculate the second modulation parameters of the converter after closed-loop control based on the first modulation parameters; wherein, the first modulation parameter and the second modulation parameter are, respectively, a modulation ratio and a shift ratio, the shift ratio including an outer shift ratio and an inner shift ratio; the calculation of the second modulation parameters of the matrix circuit in the converter after closed-loop control based on the first modulation parameters includes: Substituting the first modulation parameter into the target calculation formula, the second modulation parameter of the matrix circuit is calculated; wherein, the target calculation formula includes a dual-phase-shift mode calculation formula and a single-phase-shift mode calculation formula; the dual-phase-shift mode calculation formula is expressed as: The calculation formula for the single-phase shift mode is expressed as follows: Compared to the aforementioned outward movement, Compared to the inward shift, , , , These are preset constant values. U o This indicates the output voltage. M This indicates the modulation ratio. U m Indicates the peak value of the three-phase AC phase voltage; A generation module is used to generate multiple second target drive signals based on the second modulation parameters; wherein each second target drive signal is used to control the corresponding second target switch to turn on or off, so as to realize the soft switching of the converter; the first target switch and the second target switch are respectively the switch on the matrix circuit and the switch on the full-bridge circuit; the drive signal corresponding to the modulation ratio is used to control the switch on or off of each of the switches on the matrix circuit, and the drive signal corresponding to the shift ratio is used to control the switch on or off of each of the switches on the full-bridge circuit.

8. A soft-switching control system, characterized in that, Includes a converter and a controller electrically connected to the converter, wherein: The converter includes a matrix circuit, an inductor, an isolation transformer, and a full-bridge circuit. The matrix circuit is connected to the primary side of the isolation transformer through the inductor, and the full-bridge circuit is connected to the secondary side of the isolation transformer. The matrix circuit is used to connect to three-phase AC power. The matrix circuit and the full-bridge circuit are each equipped with multiple switching transistors. The controller is used to perform the steps in the method of any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the controller, it implements the steps of the method according to any one of claims 1 to 6.

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