CN203967994U - Unity power factor single-stage AC-DC converter - Google Patents

Abstract

The utility model discloses a unit power factor single-stage AC-DC converter, which includes an AC power supply and a filter circuit connected with the AC power supply. The filter circuit transmits the filtered signal to a rectifier for rectification processing, and the signal rectified by the rectifier is transmitted to The input end of the isolated DC-DC converter and the output end of the isolated DC-DC converter are connected in parallel with the capacitor C1 and then connected to the load. The utility model can realize bidirectional single-stage AC-DC or DC-AC isolation conversion, which is convenient for battery charging/discharging or photovoltaic grid-connected power generation, and can also realize cascade modular single-stage isolation AC-DC conversion as a power electronic transformer For high voltage AC input applications.

Description

Unity Power Factor Single-Stage AC-DC Converter

technical field

The utility model relates to the technical field of power electronic conversion, in particular to an isolated single-stage AC-DC isolation converter with a unit power factor and a control method thereof. the

Background technique

The AC-DC isolated converter is generally composed of a rectifier and an isolated DC-DC converter. This type of AC-DC converter has a low power factor because a large-capacity filter capacitor needs to be connected in parallel after the rectifier. In order to improve the power factor, in the prior art, a power factor correction (Power Factor Correction, PFC) circuit is generally added between the rectifier and the isolated DC-DC converter, as shown in Fig. 1 . This type of AC-DC isolated converter adopts two-stage high-frequency conversion, that is, PFC high-frequency conversion and isolated DC-DC high-frequency conversion, which reduces the conversion efficiency, because these two high-frequency conversions require two sets of control systems with different functions , so it has the disadvantages of complex control circuit and high cost. the

Utility model content

In order to solve the shortcomings of the existing technology, the utility model discloses a unit power factor single-stage AC-DC isolation converter. Output voltage/current wide range control and other advantages. the

In order to achieve the above object, the concrete scheme of the utility model is as follows:

Unity power factor single-stage AC-DC converter, including an AC power supply and a filter circuit connected to the AC power supply, the filter circuit transmits the filtered signal to the rectifier for rectification processing, and the signal rectified by the rectifier is transmitted to the isolated DC-DC The input end of the converter and the output end of the isolated DC-DC converter are connected in parallel with the capacitor C1 and then connected to the load. the

The rectifier is a passive rectifier, which is a single-phase full-bridge rectifier circuit composed of four diodes. the

The rectifier is an active H-bridge rectifier, which is an H-bridge conversion circuit composed of four power switch tubes with antiparallel diodes. the

The isolated DC-DC converter includes a high-frequency transformer, a primary-side conversion circuit connected to the primary side of the high-frequency transformer, and a secondary-side conversion circuit connected to the secondary side of the high-frequency transformer, and the high-frequency transformer consists of At least one inductor is connected in series with the high frequency transformer winding. the

The inductance is an independent inductance or a leakage inductance of the high frequency transformer. the

The primary-side conversion circuit and the secondary-side conversion circuit are H-bridge conversion circuits composed of four power switch tubes with anti-parallel diodes. the

The primary-side conversion circuit and the secondary-side conversion circuit are a half-bridge conversion circuit composed of two power switch tubes with anti-parallel diodes and two capacitors, wherein the two power switch tubes are connected in series to form the half-bridge conversion circuit One bridge arm of the converter, and the two capacitors are connected in series to form the other bridge arm of the half-bridge converter. the

The primary-side conversion circuit and the secondary-side conversion circuit are an H-bridge hybrid converter composed of two power switch tubes with antiparallel diodes and two diodes, wherein one diode is connected in series with a power switch tube to form the H-bridge converter One bridge arm of the converter, another diode is connected in series with another power switch tube to form the other bridge arm of the H-bridge converter, that is, the two upper tubes or two lower tubes of the H-bridge converter are replaced by diodes, forming The H-bridge hybrid conversion circuit. the

A control system for a single-stage AC-DC converter with unity power factor, including a composite controller, the composite controller receiving the secondary-side DC bus voltage and current signal of the single-stage AC-DC isolation converter, and the secondary-side DC bus reference voltage , current signal, the composite controller processes the received voltage and current and converts it into an AC current reference effective value;

The AC current reference effective value and voltage value are calculated by the multiplier as the primary current reference signal, and the primary current reference signal, primary current signal, primary voltage signal and secondary voltage signal are all input to the current controller;

The output signal of the current controller is connected to the two input terminals of the switch signal generator, and the output signal of the switch signal generator is connected to the power switch tube of the isolated DC-DC converter in the single-stage AC-DC isolated converter for controlling the power For switching on and off of the switch tube, one input terminal of the switch signal generator is also connected with the switch synchronous signal. the

The AC current reference effective value and voltage value are calculated by a multiplier, and the voltage value in the primary side current reference signal is the output value after the primary side DC bus voltage detection signal is divided by the input AC voltage rated value U _sN by the divider.

After the AC current reference effective value and voltage value are calculated by a multiplier, the voltage value in the primary side current reference signal is the absolute value |u _sin | of the unit amplitude sinusoidal signal u _sin of the same frequency and phase as the input AC power supply u _s .

A cascade modular unit power factor single-stage AC-DC isolated converter system, which includes N (N is an integer greater than or equal to 1) said unit power factor single-stage AC-DC isolated converters, N primary A side current control unit and a secondary side composite controller; the primary side current control unit includes the current controller, a switch signal generator, a multiplier and the divider. the

The AC input ends of the N single-stage AC-DC isolation converters are connected in cascade, and the positive/negative poles of the secondary DC busbars of the N single-stage AC-DC isolation converters are respectively connected in parallel. The primary side current control unit corresponds to each of the unit power factor single-stage AC-DC isolation converters, and the output signal _Is ^* of the secondary side composite controller is connected to the input of each of the primary side current control units Terminal I _s ^* ; the frequency of the switching synchronous signal CLK of the N primary-side current control units is the same, and CLK1, CLK2, ..., CLKn can be sequentially shifted by 180°/N.

A control method for a control system of a unit power factor single-stage AC-DC converter, comprising the following steps:

Step 1: detecting the primary side DC bus voltage u _d1 and current i d1 and the secondary side DC bus voltage u _d2 and current i _d2 of the isolated DC-DC converter in the AC _- DC isolation converter;

Step 2: The secondary-side DC bus voltage reference u _d2 ^* and current reference i _d2 ^* , as well as the detected values of the secondary-side DC bus voltage u _d2 and current i _d2 are processed by the secondary-side composite controller to generate an input AC Current RMS reference I _s ^* ;

Step 3: divide the primary side DC bus voltage u _d1 by the input AC voltage rating U _sN , and then multiply the input AC current RMS reference I _s ^* to obtain the primary side DC bus current reference i _d1 ^* , namely In the formula, U _sN represents the rated value of the input AC voltage;

Step 4: Send the detection values of the primary-side DC bus current reference i _d1 ^* , the primary-side DC bus voltage u _d1 and current i _d1 , and the secondary-side DC bus voltage u _d2 to the primary-side current controller for comprehensive processing After output F ₁ and F ₂ , wherein F ₁ and F ₂ are the control quantities of the primary side and secondary side converters respectively;

Step 5: Send F ₁ and F ₂ to the switching signal generator unit for processing, and output the switching control signals for generating the primary side and secondary side power switch tubes of the isolated DC-DC converter.

The first step also includes detecting the input AC voltage u _s of the AC-DC isolation converter, and replacing the primary-side DC bus voltage u _d1 after an absolute value calculation, that is, u _d1 =|u _s |.

In the step 1 and step 2, when it is not necessary to control the secondary side DC bus current _id2 , the detection and processing of _id2 is ignored.

In the first step, the detection of the bus currents _id1 and _id2 may be replaced by detecting the current of the power switch tube.

In the third step, u _d1 /U _sN can be replaced by the absolute value |u _sin | of the unit amplitude sinusoidal signal u _sin of the same frequency and phase as the input AC voltage u _s , and the primary side DC bus current reference i _d1 ^* is i _d1 ^* = I _s ^* |*u _sin |.

Working principle: the output signal of the switching signal generator is connected to the power switch tube of the isolated DC-DC converter in the single-stage AC-DC isolated converter, and is used to control the on-off of the power switch tube; the output of the current controller Signals _F1 and _F2 are connected to the two input terminals of the switch signal generator, and a switch synchronous signal CLK is connected to the third input terminal of the switch signal generator; the output signal I _s ^* of the secondary side compound controller is used as the input AC current RMS reference, the isolated DC-DC converter primary side DC bus voltage detection signal u _d1 is divided by the divider by the input AC voltage rating U _sN and then output u _unit , namely After multiplying I _s ^* and u _unit by a multiplier, the output is the primary side current reference signal i _d1 ^* , that is The output signal i _d1 ^* of the multiplier, the primary side DC bus voltage detection signal u _d1 and the current detection signal i _d1 of the isolated DC-DC converter, and the secondary side DC bus voltage detection signal of the isolated DC-DC converter u _d2 is connected to the input of the current controller. The secondary side DC bus voltage u _d2 and current i _d2 detection signals and the secondary side DC bus voltage u _d2 ^* and current reference signal i _d2 ^* are connected to the input terminal of the secondary side composite controller. The secondary side compound controller realizes the closed-loop control of the secondary side voltage or current. When the secondary side load is a storage battery or a solar battery, the secondary side composite controller realizes the closed-loop control of charging and discharging of the battery. The switch signal generator controls the on-off of the primary side converter switch tube of the isolated DC-DC converter according to the input signal _F1 and the CLK signal, and controls the isolated DC-DC converter according to the input signal _F2 and the CLK signal. The switch tube of the secondary side converter of the DC converter is turned on and off, and the CLK signal is a switch synchronization signal. The switch signal generator can generate an output switch control signal by phase-shift control, peak current control or other control methods.

The output u _unit =u _d1 /U _sN of the divider can be replaced by the absolute value |u _sin | of the unit amplitude sinusoidal signal u _sin of the same frequency and phase as the input AC voltage u _s , that is, the primary side DC bus The current reference i _d1 ^* is i _d1 ^* = I _s ^* * |u _sin |.

A cascaded modular unit power factor single-stage AC-DC isolation converter system, the AC input terminals of the N single-stage AC-DC isolation converters are connected in cascade, that is, the first single-stage AC-DC The first AC input terminal ac1 of the isolation converter is connected to an input terminal of the AC power supply, and the first AC input terminal ac1 of the second single-stage AC-DC isolation converter is connected to the first single-stage AC-DC isolation converter The second AC input end ac2 of the third single-stage AC-DC isolation converter is connected to the second AC input end ac2 of the second single-stage AC-DC isolation converter, and so on , the first AC input end ac1 of the Nth single-stage AC-DC isolation converter is connected to the second AC input end ac2 of the N-1th single-stage AC-DC isolation converter, and the Nth single-stage AC-DC isolation The second AC input terminal ac2 of the converter is connected to the other input terminal of the AC power supply. The positive/negative poles of the secondary DC buses of the N single-stage AC-DC isolated converters are respectively connected in parallel, that is, the positive poles of the secondary DC buses of the N single-stage AC-DC isolated converters are connected together, and the N The negative poles of the secondary DC bus bars of the single-stage AC-DC isolation converter are connected together. Each of the primary side current control units corresponds to each of the unit power factor single-stage AC-DC isolation converters, and the output signal I _s ^* of the secondary side composite controller is connected to each of the primary side current control units. The input terminal I _s ^* of the unit. The switching synchronization signals CLK of the N primary-side current control units have the same frequency, and the phases of CLK1, CLK2, . . . , CLKn can be sequentially shifted by 180°/N.

As another improvement of the present utility model, a three-phase unit power factor single-stage AC-DC isolation converter system includes three N (N is an integer greater than or equal to 1) modular single-stage AC-DC isolation conversion Inverter system and a secondary-side composite controller, in which three N modular single-stage AC-DC isolated converters are connected in Y shape or △ shape to form a three-phase single-stage AC-DC isolated converter system; the N modules The current reference input terminals I _s ^* of the simplified single-stage AC-DC isolation converters are connected together and connected with the output terminal I _s ^* of the secondary-side composite controller.

The beneficial effects of the utility model:

(1) The utility model provides a single-stage AC-DC isolation converter circuit. The whole conversion system only needs one stage of high-frequency conversion link and one stage of large-capacity capacitor filter link, which improves the conversion efficiency and reduces the cost. the

(2) The utility model can realize unity power factor, has the capability of raising and lowering voltage, and can realize wide-range control of output voltage/current. the

(3) The utility model can adopt the cascading modular technology to realize automatic voltage equalization between modules, and can be used as a power electronic transformer for high-voltage AC input applications. the

(4) The utility model can be used in a three-phase unit power factor single-stage AC-DC isolation converter. the

(5) The utility model can realize bidirectional single-stage AC-DC or DC-AC isolation conversion, which is convenient for battery charging/discharging or photovoltaic grid-connected power generation. the

Description of drawings

Figure 1 is an existing two-stage AC-DC isolation converter;

Fig. 2 is the single-stage AC-DC isolation converter of the present utility model;

Fig. 3 is a kind of passive rectifier topological structure;

Figure 3a is an H-bridge active rectifier topology;

Fig. 4 is the synchronous rectification control unit of the H bridge active rectifier of Fig. 3a;

Figure 5 is a DC-DC full-bridge isolated converter main circuit topology;

Fig. 5 a is another form of Fig. 5;

Figure 6 is a DC-DC half-bridge isolated converter main circuit topology;

Fig. 6a is another form of Fig. 6;

Figure 7 is a bidirectional DC-DC full-bridge isolated converter main circuit topology;

Fig. 8 is a kind of single-stage AC-DC isolation converter control system of the present utility model;

Fig. 9 is another kind of single-stage AC-DC isolation converter control system of the present utility model;

Fig. 10 is the cascaded modularized single-stage AC-DC isolation converter system of the present invention;

Figure 11 is a three-phase Y-connection cascaded modular single-stage AC-DC isolation converter system of the present invention;

Figure 11a is a three-phase △-shaped connection cascaded modular single-stage AC-DC isolation converter system of the present invention;

Among them, 1. Filter circuit, 2. Rectifier, 3. Isolated DC-DC converter, 4. Single-stage AC-DC isolated converter, 5. Secondary side composite controller, 6. Primary side current control unit, 7. , current controller, 8, switch signal generator, 9, multiplier, 10, divider, 11, phase-locked loop (PLL), 12, comparator, 13, inverter, 14, synchronous rectification control unit, 15 , N-module single-stage AC-DC isolation converter system. the

Detailed ways:

The utility model is described in detail below in conjunction with accompanying drawing:

Figure 2 shows the main circuit block diagram of the unit power factor single-stage AC-DC isolation converter of the present invention, which includes an AC side filter circuit 1, a rectifier circuit 2 and an isolated DC-DC converter 3. There is no need to connect a large-capacity filter capacitor in parallel between the rectifier circuit 2 and the isolated DC-DC converter 3 . the

Fig. 3 shows a passive rectifier circuit structure Fig. 2, including four diodes Z1-Z4, forming a known single-phase full-bridge rectifier circuit. the

Fig. 3a shows an active H-bridge rectifier circuit structure Fig. 2, which includes four power switch tubes Q1-Q4 with anti-parallel diodes, forming a known H-bridge conversion circuit. the

FIG. 4 shows the synchronous rectification control unit 14 of the active H-bridge rectifier 2. In the figure, the comparator 12 realizes the comparison of the input AC voltage, and the inverter 13 realizes logic inversion. When the input AC voltage u _s is greater than 0, the comparator 12 outputs a logic "1", and the inverter 13 outputs a logic "0", which controls the switching tubes Q1 and Q1 of the active H-bridge rectifier shown in Figure 3a Q4 is turned on, and Q2 and Q3 are turned off. Conversely, when the input AC voltage u _s is less than 0, the comparator 12 outputs a logic "0", and the inverter 13 outputs a logic "1". The control is shown in Figure 3a The switching tubes Q2 and Q3 of the active H-bridge rectifier are turned on, and Q1 and Q4 are turned off.

Figure 5 shows a main circuit topology of a unidirectional DC-DC full-bridge isolated converter. In the figure, the primary side is an H-bridge high-frequency converter, and the secondary side is an H-bridge hybrid conversion circuit (ie, The two upper tubes or two lower tubes of the device are replaced by diodes), between the primary side and the secondary side is a high-frequency transformer Tr with an inductance Ls in series (the inductance Ls can be replaced by the leakage inductance of the transformer Tr). This topology has step-up/buck control capability, i.e. or The power in this topology flows in one direction, and the power flows from the primary side to the secondary side. The rectifier circuit 2 can be shown in FIG. 3 .

Figure 5a shows another topology of the main circuit of the unidirectional DC-DC full-bridge isolated converter. An active H-bridge rectifier as shown in Figure 3a is used. the

Figure 6 shows a main circuit topology of a unidirectional DC-DC half-bridge isolated converter. The difference from Figure 5 is that the primary side of Figure 6 is a half-bridge high-frequency converter. the

Figure 6a shows a main circuit topology of a unidirectional DC-DC half-bridge isolated converter. The difference from Figure 5a is that the secondary side of Figure 6a is a half-bridge high-frequency converter. the

Figure 7 shows a main circuit topology of a bidirectional DC-DC full-bridge isolated converter. In the figure, both the primary side and the secondary side use H-bridge high-frequency converters. An H-bridge rectifier that enables bidirectional flow of power between the primary and secondary sides. This topology also has buck-boost control capability, that is, or

Example 1:

The rectifier 2 in Fig. 2 is realized by Fig. 3, and the DC-DC isolated converter 3 is realized by Fig. 5, which forms a main circuit topology of a unidirectional unit power factor single-stage full-bridge AC-DC isolated converter. The load is transmitted from the input alternating current (AC) side to the direct current (DC) side (that is, in Figure 2, power is transmitted from left to right). The detection of the primary side DC bus current i _d1 can be replaced by detecting the switching tube current i _s2 and i _s4 or i _s1 and i _s3 after addition, and the detection of the secondary side DC bus current i _d2 can be detected by detecting the switching tube current i _s6 and i _s8 Substitute after addition.

Example 2:

The rectifier 2 in Fig. 2 is realized by Fig. 3a, and the DC-DC isolated converter 3 is realized by Fig. 5a, which forms a main circuit topology of a unidirectional unit power factor single-stage full-bridge grid-connected DC-AC isolated converter. Its power is transmitted from the DC side (DC) load to the input AC side (AC) side (that is, in Figure 2, the power is transmitted from the right side to the left side). The detection of the primary side DC bus current i _d1 can be replaced by the detection of the switching tube currents i _s2 and i _s4 after addition, and the detection of the secondary side DC bus current i _d2 can be detected by the detection of the switching tube currents i _s6 and i _s8 or i _s5 and i _s7 Substitute after addition.

Example 3:

The rectifier 2 in Fig. 2 is realized by Fig. 3, and the DC-DC isolated converter 3 is realized by Fig. 6, which constitutes a unidirectional unit power factor single-stage half-bridge type AC-DC isolated converter main circuit topology, and its power The load is transmitted from the input alternating current (AC) side to the direct current (DC) side (that is, in Figure 2, power is transmitted from left to right). the

Example 4:

The rectifier 2 in Fig. 2 is realized by Fig. 3a, and the DC-DC isolated converter 3 is realized by Fig. 6a, which constitutes a unidirectional unit power factor single-stage half-bridge grid-connected DC-AC isolated converter main circuit topology, Its power is transmitted from the DC side (DC) load to the input AC side (AC) side (that is, in Figure 2, the power is transmitted from the right side to the left side). the

Embodiment 5:

The rectifier 2 in Fig. 2 is realized by Fig. 3a, and the DC-DC isolated converter 3 is realized by Fig. 7, which constitutes a bidirectional unit power factor single-stage full-bridge AC-DC isolated converter main circuit topology, and its power can be Realize two-way transmission. The detection of the primary side DC bus current i _d1 can be replaced by detecting the switching tube current i _s2 and i _s4 or i _s1 and i _s3 after addition, and the detection of the secondary side DC bus current i _d2 can be detected by detecting the switching tube current i _s6 and i _s8 Or i _s5 and i _s7 are replaced after addition.

Example 6

FIG. 8 shows a single-stage AC-DC isolation converter control system of the present invention, which includes a secondary-side composite controller 5 and a primary-side current control unit 6 . The primary side current control unit 6 includes a current controller 7 , a switch signal generator 8 , a multiplier 9 and a divider 10 . The output signal of the switch signal generator 8 is connected to the power switch tube of the isolated DC-DC converter 3 in the single-stage AC-DC isolation converter 4, and is used to control the on-off of the power switch tube; the current The output signals _F1 and _F2 of the controller 7 are connected to the two input terminals of the switch signal generator 8, and a switch synchronization signal CLK is connected to the third input terminal of the switch signal generator 8; The output signal I _s ^* of the controller 5 is used as a reference for the effective value of the input AC current, and the detection signal u _d1 of the primary side DC bus voltage of the isolated DC-DC converter 3 is divided by the rated value of the input AC voltage by the divider 10 Output u _unit after U _sN , namely After multiplying I _s ^* and u _unit by the multiplier 9, the primary side current reference signal i _d1 ^* is output, namely The output signal i _d1 ^* of the multiplier 9 , the primary side DC bus voltage detection signal u _d1 and the current detection signal i _d1 of the isolated DC-DC converter 3 , and the isolated DC-DC converter 3 The secondary side DC bus voltage detection signal u _d2 is connected to the input terminal of the current controller 7 . The secondary side DC bus voltage u _d2 and current i _d2 detection signals and the secondary side DC bus voltage u _d2 ^* and current reference signal i _d2 ^* are connected to the input terminal of the secondary side composite controller 5 .

The secondary-side composite controller 5 implements closed-loop control of secondary-side voltage or current. When the secondary side load is a storage battery or a solar battery, the secondary side composite controller 5 realizes closed-loop control of charging and discharging of the battery. the

The switch signal generator 8 controls the on-off of the primary-side converter switch tubes S1 _- S4 of the isolated DC-DC converter 3 according to the input signal F1 and the CLK signal, and according to the input signal _F2 and the CLK signal, Controlling the on-off of the secondary-side converter switch tubes S5 - S8 of the isolated DC-DC converter 3 , wherein the CLK signal is a switch synchronization signal. The switch signal generator 8 can generate an output switch control signal by using phase shift control, peak current control or other control methods.

When the switch signal generator 8 adopts phase shift control, for embodiment 1, _F1 represents the phase shift angle between the left/right bridge arm switch signals on the primary side, and _F2 represents the phase shift angle between the secondary side and the primary side switch signals. The phase shift angle, the secondary side switches S6 and S8 are square wave complementary control. For Embodiment 2, _F2 represents the phase shift angle between the left/right bridge arm switch signals on the secondary side, _F1 represents the phase shift angle between the primary side and secondary side switch signals, and the primary side switch tubes S2 and S4 It is a square wave complementary control. For Embodiment 3, _F1 represents the pulse width of the switching signals of the primary side switching tubes S1 and S2, _F2 represents the phase shift angle between the secondary side and the primary side switching signals, and the secondary side switching tubes S6 and S8 are square waves complementary control. For Embodiment 4, _F2 represents the pulse width of the switching signals of the switching tubes S5 and S6, _F1 represents the phase shift angle between the primary side and the secondary side switching signals, and the primary side switching tubes S2 and S4 are controlled by square wave complementarity. For Embodiment 5, when the power is transmitted from the input AC side (AC) side to the DC side load (that is, in Figure 2, the power is transmitted from the left side to the right side), F ₁ represents the left/right bridge arm of the primary side The phase shift angle between the switching signals, F ₂ represents the phase shift angle between the secondary side and the primary side switching signals, the secondary side switching tubes S6 and S8 are square wave complementary control, and the switching tubes S5 and S7 are cut off; when the power When the load is transmitted from the DC side (DC) to the input AC side (AC) side (that is, power is transmitted from the right side to the left side in Figure 2), F ₂ represents the shift between the left/right bridge arm switching signals on the secondary side Phase angle, F ₁ represents the phase shift angle between the primary side and the secondary side switch signal, the primary side switch tubes S2 and S4 are square wave complementary control, and the switch tubes S1 and S3 are cut off.

When the rectifier 2 adopts the active H-bridge rectifier shown in FIG. 3 a , the synchronous rectification of the active H-bridge rectifier 2 is realized by the synchronous rectification control circuit 14 shown in FIG. 4 . the

Example 7

Fig. 9 has provided another kind of single-stage AC-DC isolation converter control system of the present utility model, and the main difference with Fig. 8 is: an input u _unit of multiplier 9 in Fig. 8 is used with described input AC voltage U _s is replaced by the absolute value |u _sin | of the unit amplitude sinusoidal signal u _sin of the same frequency and phase, where |u _sin | is the output u _sin of the phase-locked loop (PLL) 11 and then calculates the absolute value, so that the primary side DC The bus current refers to i _d1 ^* as i _d1 ^* = I _s ^* *|u _sin |.

Example 8

Figure 10 shows a cascaded modular single-stage AC-DC isolated converter system, which includes N (N is an integer greater than or equal to 1) said unit power factor single-stage AC-DC isolated converters 4, N One said primary side current control unit 6 and one secondary side compound controller 5. The AC input terminals of the N single-stage AC-DC isolation converters 4 are connected in cascade, that is, the first AC input terminal ac1 of the first single-stage AC-DC isolation converter 4 is connected to an input terminal of the AC power supply , the first AC input end ac1 of the second single-stage AC-DC isolation converter is connected to the second AC input end ac2 of the first single-stage AC-DC isolation converter 4, and the third single-stage AC-DC isolation conversion The first AC input terminal ac1 of the device 4 is connected to the second AC input terminal ac2 of the second single-stage AC-DC isolation converter 4, and so on, the first AC-DC isolation converter 4 of the Nth single-stage The AC input terminal ac1 is connected to the second AC input terminal ac2 of the N-1th single-stage AC-DC isolation converter 4, and the second AC input terminal ac2 of the Nth single-stage AC-DC isolation converter 4 is connected to the The other input terminal of the above-mentioned AC power supply. The positive/negative poles of the secondary DC buses of the N single-stage AC-DC isolated converters 4 are respectively connected in parallel, that is, the positive poles of the secondary DC buses of the N single-stage AC-DC isolated converters 4 are connected together, The negative poles of the secondary DC bus bars of the N single-stage AC-DC isolation converters 4 are connected together. the

Each of the primary side current control units 6 corresponds to each of the unit power factor single-stage AC-DC isolation converters 4, and the output signal _Is ^* of the secondary side compound controller 5 is connected to each of the primary The input terminal I _s ^* of the side current control unit 6 . The frequency of the switching synchronous signal CLK of the N primary-side current control units 6 is the same, and CLK1, CLK2, .

The unit power factor single-stage AC-DC isolation converter 4 may be composed of the unidirectional single-stage AC-DC isolation converter in Embodiments 1 to 4, or the bidirectional single-stage AC-DC in Embodiment 5. Isolation converter composition. the

Example 9

Figure 11 shows a three-phase Y-connection cascaded modular single-stage AC-DC isolated converter system, which includes three N (N is an integer greater than or equal to 1) modular single-stage AC-DC isolated converter system 15 and a compound controller 5 on the secondary side. The first AC input terminals N1 of the three N-module single-stage AC-DC isolation converter systems 15 are respectively connected to the output of the three-phase power supply, and the second terminals of the three N-module single-stage AC-DC isolation converter systems 15 The AC input terminal N2 is connected together; the current reference input terminal I _s ^* of the three-phase N module single-stage AC-DC isolation converter system 15 is connected together, and is connected with the output terminal of the secondary side compound controller 5 I _s ^* connected.

Example 10

Figure 11a shows a three-phase △-connection cascade modular single-stage AC-DC isolated converter system, which includes three N (N is an integer greater than or equal to 1) modular single-stage AC-DC isolated converter system 15 and a compound controller 5 on the secondary side. The two AC input terminals N1 and N2 of the three N-module single-stage AC-DC isolation converter systems 15 are respectively connected across the output of the three-phase power supply in sequence, that is, the a-phase N-module single-stage AC-DC isolation converter system The two AC input terminals N1 and N2 of 15 are connected across the a-phase and b-phase power output, and the two AC input terminals N1 and N2 of the b-phase N module single-stage AC-DC isolation converter system 15 are connected across the b-phase and b-phase C-phase power output, the two AC input terminals N1 and N2 of the c-phase N module single-stage AC-DC isolation converter system 15 are connected across the c-phase and a-phase power output; the three-phase N module single-stage AC-DC The current reference input terminals I _s ^* of the isolated converter system 15 are connected together and connected to the output terminal I _s ^* of said secondary side composite controller 5 .

Although the specific implementation of the utility model has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the utility model. Those skilled in the art should understand that on the basis of the technical solution of the utility model, those skilled in the art do not need to Various modifications or deformations that can be made with creative efforts are still within the protection scope of the present utility model. the

Claims (8)

1. Unity power factor single-stage AC-DC converter, which is characterized in that it includes an AC power supply and a filter circuit connected to the AC power supply, the filter circuit transmits the filtered signal to the rectifier for rectification processing, and the rectified signal through the rectifier is transmitted To the input end of the isolated DC-DC converter, the output end of the isolated DC-DC converter is connected in parallel with the capacitor C1 and then connected to the load. the 2. The single-stage AC-DC converter with unity power factor as claimed in claim 1, wherein the rectifier is a passive rectifier, a single-phase full-bridge rectifier circuit composed of four diodes. the 3. unit power factor single-stage AC-DC converter as claimed in claim 1, is characterized in that, described rectifier is active H bridge rectifier, is the H bridge conversion that the power switching tube of four band antiparallel diodes forms circuit. the 4. The unit power factor single-stage AC-DC converter as claimed in claim 1 is characterized in that, the isolated DC-DC converter comprises a high-frequency transformer, a primary-side converter connected to the primary side of the high-frequency transformer The circuit and the secondary-side conversion circuit connected to the secondary side of the high-frequency transformer, the high-frequency transformer is composed of at least one inductance connected in series with the winding of the high-frequency transformer. the 5. The single-stage AC-DC converter with unity power factor as claimed in claim 4, wherein the inductance is an independent inductance or a leakage inductance of the high frequency transformer. the 6. unit power factor single-stage AC-DC converter as claimed in claim 4, is characterized in that, described primary side conversion circuit and secondary side conversion circuit are H bridge conversion circuit. the 7. The unit power factor single-stage AC-DC converter as claimed in claim 4 is characterized in that, said primary side conversion circuit and secondary side conversion circuit are two power switch tubes with anti-parallel diodes and two A half-bridge conversion circuit composed of capacitors, wherein two power switch tubes are connected in series to form one bridge arm of the half-bridge converter, and the two capacitors are connected in series to form the other bridge arm of the half-bridge converter. the 8. The unit power factor single-stage AC-DC converter as claimed in claim 4 is characterized in that, the primary side conversion circuit and the secondary side conversion circuit are two power switch tubes with anti-parallel diodes and two An H-bridge hybrid converter composed of diodes, wherein one diode is connected in series with a power switch tube to form a bridge arm of the H-bridge converter, and the other diode is connected in series with another power switch tube to form the other bridge arm of the H-bridge converter. The bridge arms, that is, the two upper transistors or the two lower transistors of the H-bridge converter are replaced with diodes to form the H-bridge hybrid conversion circuit. the