Monopole isolation bridgeless AC / DC converter

Abstract

The single-pole isolation bridgeless AC / DC converter comprises one or more converter modules and a control module, each converter module comprises a switch module, an isolation converter, a fly-wheel diode and a load, and the switch module comprises at least two MOSFET switch tubes. The control module comprises a current inner loop reference value calculation unit, a loop control duty ratio calculation unit and a control signal generation unit, and the current inner loop reference value calculation unit is used for sampling an output voltage and comparing the output voltage with an output voltage set value to generate an output voltage error signal; outputting a current inner loop reference value by using a voltage PI controller according to the voltage error signal; the loop control duty ratio calculation unit is used for generating a loop control duty ratio according to the current inner loop reference value; and the control signal generation unit is used for generating a control signal for controlling the MOSFET switch tube according to the loop control duty ratio. According to the invention, the loss of diodes in the traditional topology is effectively reduced, the power conversion efficiency is improved, and the overall cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular, to a single-pole isolated bridgeless AC / DC converter. Background Art

[0002] Figure 1 The following shows a topological schematic diagram of an existing single-phase single-pole isolated AC / DC converter. As Figure 1 shown, an existing single-phase single-pole isolated AC / DC converter generally includes a rectifier bridge composed of 4 diodes and a MOS transistor, and this MOS transistor will work regardless of whether the mains power is positive or negative. Due to the inherent forward voltage drop of the diodes, there are relatively large losses, resulting in low overall energy efficiency.

[0003] Based on this, a new solution is needed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a single-pole isolated bridgeless AC / DC converter.

[0005] To achieve the above object, the present invention provides a single-pole isolated bridgeless AC / DC converter, including one or more converter modules and a control module. Each of the converter modules includes a switching module, an isolated converter, and a freewheeling diode. The switching module is connected between an input AC source and the primary side of the isolated converter. The secondary side of the isolated converter is connected to the load via the freewheeling diode. The switching module includes at least two MOSFET switching transistors. The control module includes a current inner-loop reference value calculation unit, a loop control duty ratio calculation unit, and a control signal generation unit. The current inner-loop reference value calculation unit is used to sample the output voltage and compare it with the output voltage set value to generate an output voltage error signal, and output a current inner-loop reference value using a voltage PI controller according to the voltage error signal. The loop control duty ratio calculation unit is used to generate a loop control duty ratio according to the current inner-loop reference value. The control signal generation unit is used to generate a control signal for controlling the MOSFET switching transistors according to the loop control duty ratio.

[0006] The single-pole isolated bridgeless AC / DC converter provided by the present invention has the following beneficial effects: In the present invention, through a bridgeless design and reducing the number of diodes, the number of diodes is reduced to 2 of the original, and only one MOS transistor works during the positive and negative half-cycles of the mains input, and the other is in a conducting state. This reduces the power borne by the MOS transistor, and a MOS transistor with a lower specification can be selected. At the same time, the loss when the MOS transistor is conducting is small, thereby improving the efficiency and reducing the cost. Brief Description of the Drawings

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on the provided drawings:

[0008] Figure 1 The figure shows a topological schematic diagram of an existing single-phase single-pole isolated AC / DC converter;

[0009] Figure 2 The figure shows a topology diagram of a single-pole single-phase isolated bridge-less AC / DC converter provided by an embodiment of the present invention. Among them, the switch module includes 2 MOSFET switches;

[0010] Figure 3 The figure shows a topology diagram of a single-pole single-phase isolated bridge-less AC / DC converter provided by another embodiment of the present invention. Among them, the switch module includes 2 MOSFET switches;

[0011] Figure 4 Shown is provided by an embodiment of the present invention Figure 2 The figure shows a circuit control diagram of the single-pole single-phase isolated bridge-less AC / DC converter;

[0012] Figure 5 Shown is Figure 4 The figure shows the overall waveform timing diagram of the circuit;

[0013] Figure 6 Shown is Figure 4 The figure shows the positive half-axis waveform detail timing diagram of the circuit;

[0014] Figure 7 Shown is provided by another embodiment of the present invention Figure 2 The figure shows a circuit control diagram of the single-pole single-phase isolated bridge-less AC / DC converter;

[0015] Figure 8 Shown is Figure 7 The figure shows the overall waveform timing diagram of the circuit;

[0016] Figure 9 Shown is Figure 7 The figure shows the positive half-axis waveform detail timing diagram of the circuit;

[0017] Figure 10 The figure shows a topology diagram of a single-pole single-phase isolated bridge-less AC / DC converter provided by an embodiment of the present invention. Among them, the switch module includes 4 MOSFET switches;

[0018] Figure 11The topology diagram of a single - pole single - phase isolated bridge - less AC / DC converter provided by another embodiment of the present invention is shown. Among them, the switch module includes 4 MOSFET switches;

[0019] Figure 12 Shown is that provided by an embodiment of the present invention Figure 10 The circuit control diagram of the single - pole single - phase isolated bridge - less AC / DC converter shown;

[0020] Figure 13 Shown is Figure 12 The overall waveform timing diagram of the circuit shown;

[0021] Figure 14 Shown is Figure 12 The positive - half - axis waveform detail timing diagram of the circuit shown;

[0022] Figure 15 Shown is that provided by another embodiment of the present invention Figure 10 The circuit control diagram of the single - pole single - phase isolated bridge - less AC / DC converter shown;

[0023] Figure 16 Shown is Figure 15 The overall waveform timing diagram of the circuit shown;

[0024] Figure 17 Shown is Figure 15 The positive - half - axis waveform detail timing diagram of the circuit shown;

[0025] Figure 18 Shown is that provided by yet another embodiment of the present invention Figure 10 The circuit control diagram of the single - pole single - phase isolated bridge - less AC / DC converter shown;

[0026] Figure 19 Shown is Figure 18 The overall waveform timing diagram of the circuit shown;

[0027] Figure 20 Shown is Figure 18 The positive - half - axis waveform detail timing diagram of the circuit shown;

[0028] Figure 21 The topology diagram of a single - pole three - phase isolated bridge - less AC / DC converter provided by an embodiment of the present invention is shown;

[0029] Figures 22 to 24 The topology diagram of a single - pole three - phase isolated bridge - less AC / DC converter provided by another embodiment of the present invention is shown;

[0030] Figure 25 Shown is that provided by an embodiment of the present invention Figure 21 The circuit control diagram of the single - pole single - phase isolated bridge - less AC / DC converter shown. Detailed implementation manners

[0031] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Typical embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] The single-pole isolated bridgeless AC / DC converter provided by the present invention includes one or more converter modules and a control module. Each of the converter modules includes a switch module, an isolated converter, and a freewheeling diode. The switch module is connected between the input AC source and the primary side of the isolated converter, and the secondary side of the isolated converter is connected to the load via the freewheeling diode. Among them, the switch module includes at least two MOSFET switches, and the control module includes a current inner-loop reference value calculation unit, a loop control duty ratio calculation unit, and a control signal generation unit. The current inner-loop reference value calculation unit is used to sample the output voltage and compare it with the output voltage set value to generate an output voltage error signal, and output a current inner-loop reference value using a voltage PI controller according to the voltage error signal; the loop control duty ratio calculation unit is used to generate a loop control duty ratio according to the current inner-loop reference value; the control signal generation unit is used to generate a control signal for controlling the MOSFET switch according to the loop control duty ratio.

[0034] In the traditional single-pole single-phase isolated AC / DC converter topology, 4 diodes and 1 MOS transistor are required. And within the positive and negative half-cycles of the mains input, the MOS transistor always works, which will increase the loss because the diode has an inherent conduction voltage drop. In the present invention, through the bridgeless design and reducing the number of diodes, the number of diodes is reduced to 2 of the original, and within the positive and negative half-cycles of the mains input, only one MOS transistor is working and the other is in the conducting state. This makes the power borne by the MOS transistor reduced, a MOS transistor with a lower specification can be selected, and at the same time, the loss when the MOS transistor is conducting is smaller, thereby improving the efficiency and reducing the cost.

[0035] Figure 2 The topology diagram of the single-pole single-phase isolated bridgeless AC / DC converter provided by the embodiment of the present invention is shown as Figure 2As shown in the figure, the switching module 110 of the single-pole single-phase isolated bridge-less AC / DC converter includes a first MOSFET switch FETD6, a second MOSFET switch FETD5, a first diode D3, and a second diode D5. The drain of the first MOSFET switch and the negative electrode of the first diode are connected to one end of the primary side of the isolation converter Tr2 via a capacitor C3. The positive electrode of the second diode and the source of the second MOSFET switch are connected to the other end of the primary side of the isolation converter Tr2. The source of the first MOSFET switch and the drain of the second MOSFET switch are connected to one end of the input AC power supply via an inductor L1. The positive electrode of the first diode and the negative electrode of the second diode are connected to the other end of the input AC power supply. The gates of the first MOSFET switch and the second MOSFET switch are respectively connected to the control signal. The freewheeling diode is the MOSFET switch FETD3, and the load is the resistor R4.

[0036] Figure 3 The figure shows the topology diagram of a single-pole single-phase isolated bridge-less AC / DC converter provided by another embodiment of the present invention. Different from Figure 2 the embodiment shown in the figure, in Figure 3 the embodiment shown in the figure, the freewheeling diode is the diode D4.

[0037] Figure 4 The figure shows the Figure 2 circuit control diagram of the single-pole single-phase isolated bridge-less AC / DC converter provided by an embodiment of the present invention. As Figure 4 shown, a control method of a battery voltage outer loop and an input current inner loop is adopted. Specifically, the loop control duty cycle calculation unit 210 obtains a current target value by multiplying the product of the current inner loop reference value and the input voltage sampling value by a proportional coefficient, generates an input current error signal according to the current target value and the input current sampling value, and then generates a loop control duty cycle by using a current PI controller according to the input current error signal. Further, in Figure 4 the embodiment shown in the figure, the PWM calculated by the loop directly acts on the first MOSFET switch FETD5 and the second MOSFET switch FETD6, that is, the control signals of the gates of the first MOSFET switch and the second MOSFET switch are the same. Figure 5 The figure shows Figure 4 the overall waveform timing diagram of the circuit shown in the figure, Figure 6 The figure shows Figure 4 the positive half-cycle waveform detail timing diagram of the circuit shown in the figure. As Figure 5 and Figure 6As shown, under the control of the control signal, the first MOSFET switch and the second MOSFET switch are turned on and off simultaneously according to the loop control duty cycle.

[0038] Figure 7 As shown in another embodiment of the present invention Figure 2 The circuit control diagram of the single-pole single-phase isolated bridgeless AC / DC converter shown. Similar to Figure 4 the embodiment shown, a control method with an outer battery voltage loop and an inner input current loop is adopted, that is, the loop control duty cycle calculation unit 210 obtains the current target value by multiplying the product of the inner current loop reference value and the input voltage sampling value by a proportionality coefficient, generates an input current error signal according to the current target value and the input current sampling value, and then generates the loop control duty cycle by using a current PI controller according to the input current error signal. Different from Figure 4 the embodiment shown, the PWM calculated by the loop is divided into positive and negative half-cycles. When the input voltage is in the positive half-cycle, the first MOSFET switch FET6 (PWM1) remains conducting, and the loop control duty cycle D acts on the second MOSFET switch FET (PWM2) 5; when the input voltage is in the negative half-cycle, the second MOSFET switch FET5 (PWM2) remains conducting, and the loop control duty cycle D acts on the first MOSFET switch FET6 (PWM1). That is, the difference from Figure 4 the embodiment shown is that in Figure 7 the embodiment shown, the control signal generation unit generates a control signal for controlling the MOSFET switch according to the loop control duty cycle and the input voltage sampling value. As Figure 9 shown, within the positive half-cycle of the input voltage, the control signal of the gate of the first MOSFET switch controls the first MOSFET switch to remain in the conducting state, and the control signal of the gate of the second MOSFET switch controls the second MOSFET switch to conduct and turn off according to the loop control duty cycle; within the negative half-cycle of the input voltage, the control signal of the gate of the second MOSFET switch controls the second MOSFET switch to remain in the conducting state, and the control signal of the gate of the first MOSFET switch controls the first MOSFET switch to conduct and turn off according to the loop control duty cycle. The constantly-on tube has no switching loss and higher efficiency.

[0039] Those skilled in the art can understand that Figure 4 and Figure 7 the circuit control diagram shown can also be applied to Figure 3 the single-pole single-phase isolated bridgeless AC / DC converter shown. The specific control process is the same as Figure 2 that, and the present invention will not repeat it here.

[0040] Figure 10 The topological diagram of the single - pole single - phase isolated bridge - less AC / DC converter provided by an embodiment of the present invention is shown. Different from Figure 2 the embodiment shown, in Figure 10 the embodiment shown, the switch module includes 4 MOSFET switches. The switch module includes a first MOSFET switch, a second MOSFET switch, a third MOSFET switch, and a fourth MOSFET switch. The drain of the first MOSFET switch and the drain of the third MOSFET switch are connected to one end of the primary side of the isolation converter. The source of the fourth MOSFET switch and the source of the second MOSFET switch are connected to the other end of the primary side of the isolation converter. The source of the first MOSFET switch and the drain of the second MOSFET switch are connected to one end of the input AC power supply. The source of the third MOSFET switch and the drain of the fourth MOSFET switch are connected to the other end of the input AC power supply. The gates of the first MOSFET switch, the second MOSFET switch, the third MOSFET switch, and the fourth MOSFET switch are connected to the control signal. The free - wheeling diode is MOSFET switch FETD4, and the load is resistor R5.

[0041] Figure 11 The topological diagram of the single - pole single - phase isolated bridge - less AC / DC converter provided by another embodiment of the present invention is shown. Among them, the switch module includes 4 MOSFET switches; different from Figure 10 the embodiment shown, in Figure 11 the embodiment shown, the free - wheeling diode is diode D6.

[0042] Figure 12 Shown is provided by an embodiment of the present invention Figure 10 the circuit control diagram of the single - pole single - phase isolated bridge - less AC / DC converter shown. As Figure 12As shown, a control method of an outer battery voltage loop and an inner input current loop is adopted. Specifically, the duty cycle calculation unit 210 of the loop control multiplies the product of the inner current reference value and the input voltage sampling value by a proportionality coefficient to obtain a current target value, generates an input current error signal based on the current target value and the input current sampling value, and then generates a loop control duty cycle by using a current PI controller based on the input current error signal; the control signal generation unit generates a control signal for controlling the MOSFET switch based on the loop control duty cycle and the input voltage sampling value. Further, the PWM calculated by the loop is divided into positive and negative half-cycles. When the input voltage is in the positive half-cycle, FET6 (PWM1) and FET8 (PWM4) are kept conducting, and the loop control duty cycle D acts on FET5 (PWM2) and FET7 (PWM3). When the input voltage is in the negative half-cycle, FET5 (PWM2) and FET7 (PWM3) are kept conducting, and the loop control duty cycle D acts on FET6 (PWM1) and FET8 (PWM4). That is, as Figure 14 shown, the control signals for the gates of the first MOSFET switch and the fourth MOSFET switch are both first control signals, and the control signals for the gates of the second MOSFET switch and the third MOSFET switch are both second control signals. In the positive half-cycle of the input voltage, under the control of the first control signal, the first MOSFET switch and the fourth MOSFET switch are kept in the conducting state. Under the control of the second control signal, the second MOSFET switch and the third MOSFET switch are turned on and off together according to the loop control duty cycle; in the negative half-cycle of the input voltage, under the control of the first control signal, the first MOSFET switch and the fourth MOSFET switch are turned on and off together according to the loop control duty cycle. Under the control of the second control signal, the second MOSFET switch and the third MOSFET switch are kept in the conducting state.

[0043] Figure 15 As shown, another embodiment of the present invention provides Figure 10 the circuit control diagram of the single-pole single-phase isolated bridge-less AC / DC converter shown. As Figure 15As shown, a control method of an outer battery voltage loop and an inner input current loop is adopted. Specifically, the duty cycle calculation unit 210 of the loop control multiplies the product of the inner current loop reference value and the input voltage sampling value by a proportionality coefficient to obtain a current target value, generates an input current error signal based on the current target value and the input current sampling value, and then generates a loop control duty cycle using a current PI controller based on the input current error signal; the control signal generation unit generates a control signal for controlling the MOSFET switch based on the loop control duty cycle and the input voltage sampling value. Further, the PWM calculated by the loop directly acts on FETD5 and FETD6 (PWM1 and PWM2 are turned on and off simultaneously); however, during the positive half-cycle, FET8 (PWM4) remains conducting and FET7 (PWM3) remains off; during the negative half-cycle, FET8 (PWM4) remains off and FET7 (PWM3) remains conducting. That is, as Figure 17 shown, the control signals for the gates of the first MOSFET switch and the second MOSFET switch are both third control signals, the control signal for the gate of the third MOSFET switch is a fourth control signal, and the control signal for the gate of the fourth MOSFET switch is a fifth control signal. Under the control of the third control signal, the first MOSFET switch and the second MOSFET switch are turned on and off simultaneously according to the loop control duty cycle; during the positive half-cycle of the input voltage, under the control of the fourth control signal, the third MOSFET switch remains in the off state, and under the control of the fifth control signal, the fourth MOSFET switch remains in the conducting state; during the negative half-cycle of the input voltage, under the control of the fourth control signal, the third MOSFET switch remains in the conducting state, and under the control of the fifth control signal, the fourth MOSFET switch remains in the off state.

[0044] Figure 18 shown, another embodiment of the present invention provides Figure 10 the circuit control diagram of the single-pole single-phase isolated bridge-less AC / DC converter shown. As Figure 18As shown in the figure, a control method with an outer battery voltage loop and an inner input current loop is adopted. Specifically, the duty cycle calculation unit 210 of the loop control multiplies the product of the inner current loop reference value and the input voltage sampling value by a proportionality coefficient to obtain a current target value, generates an input current error signal based on the current target value and the input current sampling value, and then generates a loop control duty cycle using a current PI controller based on the input current error signal; the control signal generation unit generates a control signal for controlling the MOSFET switch based on the loop control duty cycle and the input voltage sampling value. Further, the PWM calculated by the loop is divided into positive and negative half-cycles. When the input voltage is in the positive half-cycle, FET6 (PWM1) remains conducting, the loop control duty cycle D acts on FET (PWM2) 5, FET8 (PWM4) remains conducting, and FET7 (PWM3) remains off. When the input voltage is in the negative half-cycle, FET5 (PWM2) remains conducting, the loop control duty cycle D acts on FET6 (PWM1), FET8 (PWM4) remains off, and FET7 (PWM3) remains conducting. That is, as Figure 20 shown, the control signal for the gate of the first MOSFET switch is the sixth control signal, the control signal for the gate of the second MOSFET switch is the seventh control signal, the control signal for the gate of the third MOSFET switch is the eighth control signal, and the control signal for the gate of the fourth MOSFET switch is the ninth control signal; within the positive half-cycle of the input voltage, under the control of the sixth control signal, the first MOSFET switch remains in the conducting state, under the control of the seventh control signal, the second MOSFET switch turns on and off according to the loop control duty cycle, under the control of the eighth control signal, the third MOSFET switch remains in the off state, and under the control of the ninth control signal, the fourth MOSFET switch remains in the conducting state; within the negative half-cycle of the input voltage, under the control of the sixth control signal, the first MOSFET switch turns on and off according to the loop control duty cycle, under the control of the seventh control signal, the second MOSFET switch remains in the conducting state, under the control of the eighth control signal, the third MOSFET switch remains in the conducting state, and under the control of the ninth control signal, the fourth MOSFET switch remains in the off state.

[0045] Those skilled in the art can understand that Figure 12 、 Figure 15 and Figure 17 the circuit control diagrams shown can also be applied to Figure 11 the single-pole single-phase isolated bridge-less AC / DC converter shown. The specific control process is the same as Figure 10 that, and the present invention will not be elaborated herein.

[0046] The present invention provides multiple control methods for a single - pole single - phase isolated bridge - less AC / DC converter. By adopting PWM control (pulse - width modulation control), it can accurately adjust the on - and off - times of the MOSFET switches, thereby optimizing the operating state of the circuit, reducing switching losses, and improving the overall efficiency. By combining current inner - loop control and battery - voltage outer - loop control, it can maintain the stability of current and voltage, avoid fluctuations in the output voltage or current, and ensure the stability of the system. The current PI controller can adjust the error signal to make the system response more accurate. Especially when the load fluctuates or the input voltage changes, the system can still maintain good performance. Due to the adoption of a feedback control system, the circuit can quickly respond to load changes or input - voltage fluctuations, timely adjust the operating state, and thus provide a more stable output. By precisely controlling the switching state of the switches, it reduces the ineffective energy transfer, thereby improving the energy - conversion efficiency. Especially when the load is light, it can still maintain a high efficiency. The flexible adjustment of the control signal enables the system to adjust the operating parameters according to actual needs. For example, by adjusting the duty cycle of the loop control to optimize the performance and adapt to different load and input - voltage conditions.

[0047] Figure 21 The topology diagram of a single - pole three - phase isolated bridge - less AC / DC converter provided by an embodiment of the present invention is shown as follows. As Figure 21 shown, the switch module 110 of the single - pole three - phase isolated bridge - less AC / DC converter includes three identical converter modules, namely, a first converter module, a second converter module, and a third converter module. Each converter module includes a first MOSFET switch, a second MOSFET switch, a first diode, and a second diode. The drain of the first MOSFET switch and the negative pole of the first diode are connected to one end of the primary side of the isolation converter via a capacitor. The positive pole of the second diode and the source of the second MOSFET switch are connected to the other end of the primary side of the isolation converter. The source of the first MOSFET switch and the drain of the second MOSFET switch are connected to one end of the input AC power supply via an inductor. The positive pole of the first diode and the negative pole of the second diode are connected to the other end of the input AC power supply. The gates of the first MOSFET switch and the second MOSFET switch are respectively connected to the control signal. The free - wheeling diode is a MOSFET switch, and the load is a resistor.

[0048] Figure 22 The topology diagram of a single - pole three - phase isolated bridge - less AC / DC converter provided by another embodiment of the present invention is shown as follows. The difference from the Figure 22 embodiment shown is that in the Figure 22 embodiment shown, the free - wheeling diode is a diode. Figure 23FIG. 1 is a topological diagram of a single-pole three-phase isolated bridgeless AC / DC converter provided by another embodiment of the present invention. Figure 21 The embodiment shown differs in that Figure 23 In the embodiment shown, each converter module includes four MOSFET switch tubes, and the specific connection method is similar to Figure 10 The topology diagram of the single-pole single-phase isolated bridgeless AC / DC converter shown is similar, and the present invention will not be repeated here. Figure 24 FIG. 1 is a topological diagram of a single-pole three-phase isolated bridgeless AC / DC converter provided by another embodiment of the present invention. Figure 23 The embodiment shown differs in that Figure 24 In the illustrated embodiment, the freewheeling diode is a diode.

[0049] Figure 25 An embodiment of the present invention is shown Figure 21 The circuit control diagram of the single-pole single-phase isolated bridgeless AC / DC converter is shown in FIG. Figure 25 As shown, the control signal generating unit 230 includes a first control signal generating subunit 2301, a second control signal generating subunit 2302 and a third control signal generating subunit 2303. The loop control duty cycle calculating unit 210 generates an output current error signal according to the current inner loop reference value and the output current sampling value, and then generates a current loop output using a current PI controller according to the output current error signal, and generates a loop control duty cycle according to the product of the current loop output and the duty cycle feedforward; the first control signal generating subunit generates a control signal for controlling the MOSFET switch tube of the first converter module according to the loop control duty cycle and the AC input voltage sampling of the first converter module; the second control signal generating subunit generates a control signal for controlling the MOSFET switch tube of the second converter module according to the loop control duty cycle and the AC input voltage sampling of the second converter module; the third control signal generating subunit generates a control signal for controlling the MOSFET switch tube of the third converter module according to the loop control duty cycle and the AC input voltage sampling of the third converter module. In this embodiment, the control without AC side current sampling is adopted, and the control mode of battery voltage outer loop and battery current inner loop is adopted. The duty cycle required for control is calculated by multiplying the current loop output with the duty cycle feedforward. This scheme can save three AC side current samplings. Saving AC side current sampling not only reduces the cost, but also improves the simplicity of the circuit and the reliability of the system, while optimizing the performance of the system. Figure 6 , 10 The specific wave generation methods shown in 15 and 18 can be directly applied to the three-phase control scheme and will not be described in detail here.

[0050] It can be understood by those skilled in the art that Figure 25The circuit control diagram shown can also be applied to Figures 22 - 25 the single - pole three - phase isolated bridge - less AC / DC converter shown. The specific control process is the same as that of Figure 21 which, and the details will not be repeated in this invention.

[0051] In the specification provided herein, a large number of specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well - known methods, structures and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0052] Similarly, it should be understood that, in order to streamline this disclosure and assist in understanding one or more of the various inventive aspects, in the foregoing description of exemplary embodiments of the invention, the various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the invention.

[0053] Those skilled in the art will appreciate that the modules in the devices in the embodiments can be adaptively changed and disposed in one or more devices different from those of the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition, they can be divided into multiple sub - modules or sub - units or sub - components. Except that at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract and drawings) and all the processes or units of any method or device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0054] In addition, those skilled in the art will be able to understand that, although some of the embodiments herein include certain features included in other embodiments but not others, the combination of features of different embodiments is meant to be within the scope of the invention and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0055] Each component embodiment of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or in any other form.

[0056] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In the unit claims listing several devices, several of these devices can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names.

Claims

1. A single - pole isolated bridgeless AC / DC converter, characterized in that, It includes one or more converter modules and a control module. Each of the converter modules includes a switch module, an isolation converter, and a freewheeling diode. The switch module is connected between the input AC source and the primary side of the isolation converter. The secondary side of the isolation converter is connected to the load via the freewheeling diode. The switch module includes at least two MOSFET switches. The control module includes a current inner-loop reference value calculation unit, a loop control duty ratio calculation unit, and a control signal generation unit. The current inner-loop reference value calculation unit is used to sample the output voltage and compare it with the output voltage set value to generate an output voltage error signal, and output a current inner-loop reference value using a voltage PI controller according to the voltage error signal. The loop control duty ratio calculation unit is used to generate a loop control duty ratio according to the current inner-loop reference value. The control signal generation unit is used to generate a control signal for controlling the MOSFET switches according to the loop control duty ratio.

2. The single-pole isolated bridge-less AC / DC converter according to claim 1, wherein The loop control duty ratio calculation unit obtains a current target value by multiplying the product of the current inner-loop reference value and the input voltage sampling value by a proportionality coefficient, generates an input current error signal according to the current target value and the input current sampling value, and then generates a loop control duty ratio using a current PI controller according to the input current error signal.

3. The single-pole isolated bridge-less AC / DC converter according to claim 2, characterized in that It includes one converter module. The switch module includes a first MOSFET switch, a second MOSFET switch, a first diode, and a second diode. The drain of the first MOSFET switch and the negative electrode of the first diode are connected to one end of the primary side of the isolation converter. The positive electrode of the second diode and the source of the second MOSFET switch are connected to the other end of the primary side of the isolation converter. The source of the first MOSFET switch and the drain of the second MOSFET switch are connected to one end of the input AC power supply. The positive electrode of the first diode and the negative electrode of the second diode are connected to the other end of the input AC power supply. The gates of the first MOSFET switch and the second MOSFET switch are respectively connected to the control signal.

4. The single-pole isolated bridge-less AC / DC converter according to claim 3, characterized in that, The control signals of the gates of the first MOSFET switch and the second MOSFET switch are the same. Under the control of the control signal, the first MOSFET switch and the second MOSFET switch turn on and off simultaneously according to the loop control duty ratio.

5. The single-pole isolated bridge-less AC / DC converter according to claim 3, wherein The control signal generation unit generates a control signal for controlling the MOSFET switch according to the loop control duty ratio and the sampled value of the input voltage. During the positive half-cycle of the input voltage, the control signal of the gate of the first MOSFET switch controls the first MOSFET switch to remain in the on state, and the control signal of the gate of the second MOSFET switch controls the second MOSFET switch to turn on and off according to the loop control duty ratio; during the negative half-cycle of the input voltage, the control signal of the gate of the second MOSFET switch controls the second MOSFET switch to remain in the on state, and the control signal of the gate of the first MOSFET switch controls the first MOSFET switch to turn on and off according to the loop control duty ratio.

6. The single-pole isolated bridge-less AC / DC converter according to claim 2, characterized in that It includes a converter module. The control signal generation unit generates a control signal for controlling the MOSFET switch according to the loop control duty ratio and the sampled value of the input voltage. The switch module includes a first MOSFET switch, a second MOSFET switch, a third MOSFET switch, and a fourth MOSFET switch. The drain of the first MOSFET switch and the drain of the third MOSFET switch are connected to one end of the primary side of the isolation converter. The source of the fourth MOSFET switch and the source of the second MOSFET switch are connected to the other end of the primary side of the isolation converter. The source of the first MOSFET switch and the drain of the second MOSFET switch are connected to one end of the input AC power supply. The source of the third MOSFET switch and the drain of the fourth MOSFET switch are connected to the other end of the input AC power supply. The gates of the first MOSFET switch, the second MOSFET switch, the third MOSFET switch, and the fourth MOSFET switch are connected to the control signal.

7. The single-pole isolated bridge-less AC / DC converter according to claim 6, wherein The control signals of the gates of the first MOSFET switch and the fourth MOSFET switch are both the first control signal, and the control signals of the gates of the second MOSFET switch and the third MOSFET switch are both the second control signal. During the positive half-cycle of the input voltage, under the control of the first control signal, the first MOSFET switch and the fourth MOSFET switch remain in the on state. Under the control of the second control signal, the second MOSFET switch and the third MOSFET switch turn on and off simultaneously according to the loop control duty ratio. During the negative half-cycle of the input voltage, under the control of the first control signal, the first MOSFET switch and the fourth MOSFET switch turn on and off simultaneously according to the loop control duty ratio. Under the control of the second control signal, the second MOSFET switch and the third MOSFET switch remain in the on state.

8. The single-pole isolated bridgeless AC / DC converter according to claim 6, characterized in that, The control signals for the gates of the first MOSFET switch and the second MOSFET switch are both the third control signal, the control signal for the gate of the third MOSFET switch is the fourth control signal, and the control signal for the gate of the fourth MOSFET switch is the fifth control signal. Under the control of the third control signal, the first MOSFET switch and the second MOSFET switch turn on and off simultaneously according to the loop control duty cycle. During the positive half - cycle of the input voltage, under the control of the fourth control signal, the third MOSFET switch remains in the off state, and under the control of the fifth control signal, the fourth MOSFET switch remains in the on state. During the negative half - cycle of the input voltage, under the control of the fourth control signal, the third MOSFET switch remains in the on state, and under the control of the fifth control signal, the fourth MOSFET switch remains in the off state.

9. The single-pole isolated bridge-less AC / DC converter according to claim 6, wherein, The control signal for the gate of the first MOSFET switch is the sixth control signal, the control signal for the gate of the second MOSFET switch is the seventh control signal, the control signal for the gate of the third MOSFET switch is the eighth control signal, and the control signal for the gate of the fourth MOSFET switch is the ninth control signal. During the positive half - cycle of the input voltage, under the control of the sixth control signal, the first MOSFET switch remains in the on state, under the control of the seventh control signal, the second MOSFET switch turns on and off simultaneously according to the loop control duty cycle, under the control of the eighth control signal, the third MOSFET switch remains in the off state, and under the control of the ninth control signal, the fourth MOSFET switch remains in the on state. During the negative half - cycle of the input voltage, under the control of the sixth control signal, the first MOSFET switch turns on and off simultaneously according to the loop control duty cycle, under the control of the seventh control signal, the second MOSFET switch remains in the on state, under the control of the eighth control signal, the third MOSFET switch remains in the on state, and under the control of the ninth control signal, the fourth MOSFET switch remains in the off state.

10. The single-pole isolated bridge-less AC / DC converter according to claim 1, characterized in that, It includes a first converter module, a second converter module, and a third converter module. The control signal generation unit includes a first control signal generation sub - unit, a second control signal generation sub - unit, and a third control signal generation sub - unit. The loop control duty cycle calculation unit generates an output current error signal based on the current inner loop reference value and the output current sampling value, then generates a current loop output using a current PI controller based on the output current error signal, and generates a loop control duty cycle based on the product of the current loop output and the duty cycle feedforward; the first control signal generation subunit generates a control signal for controlling the MOSFET switch of the first converter module based on the loop control duty cycle and the AC input voltage sampling of the first converter module; the second control signal generation subunit generates a control signal for controlling the MOSFET switch of the second converter module based on the loop control duty cycle and the AC input voltage sampling of the second converter module; the third control signal generation subunit generates a control signal for controlling the MOSFET switch of the third converter module based on the loop control duty cycle and the AC input voltage sampling of the third converter module.

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