CN115065230A - Three-phase bridgeless SEPIC type PFC converter - Google Patents
Three-phase bridgeless SEPIC type PFC converter Download PDFInfo
- Publication number
- CN115065230A CN115065230A CN202210856098.5A CN202210856098A CN115065230A CN 115065230 A CN115065230 A CN 115065230A CN 202210856098 A CN202210856098 A CN 202210856098A CN 115065230 A CN115065230 A CN 115065230A
- Authority
- CN
- China
- Prior art keywords
- phase
- energy storage
- switches
- switch
- bidirectional switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4233—Arrangements for improving power factor of AC input using a bridge converter comprising active switches
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P80/00—Climate change mitigation technologies for sector-wide applications
- Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Rectifiers (AREA)
- Dc-Dc Converters (AREA)
Abstract
A three-phase bridgeless SEPIC type PFC converter solves the problems that the utilization rate of topological components of the existing SEPIC type three-phase PFC converter is low and current distortion is caused by junction capacitance of a power switch, and belongs to the field of three-phase bridgeless PFC converter topology. The three-phase power supply comprises three input filter inductors, three energy storage capacitors, three energy storage inductors, three groups of bidirectional switches, six switches and two output filter capacitors, wherein the six switches are divided into three groups of unidirectional switches, and each group comprises two switches; the single-phase conversion circuits in the three-phase conversion are the same and share two output filter capacitors; compared with the existing topology, the number of semiconductor power devices, inductors and capacitors is optimal, and the utilization rate of the devices is high. Meanwhile, the critical conduction mode control is adopted, the power factor correction of the input side is realized according to the conduction time control equation, the current distortion problem is effectively solved, the conduction loss of the converter can be further reduced, and the efficiency of the converter is effectively improved.
Description
Technical Field
The invention relates to a wide-gain novel three-phase bridgeless SEPIC type PFC converter based on CRM (critical conduction mode) control, and belongs to the field of three-phase bridgeless PFC converter topology.
Background
The three-phase PFC converter topology based on the SEPIC circuit has the advantages of simple circuit structure, good power factor correction effect, wide output voltage regulation range and the like, and is widely applied to the fields of middle and small power such as LED driving power supplies, battery chargers and the like. The input side of a conventional SEPIC-type PFC converter usually introduces a rectifier bridge composed of diodes to rectify the input voltage, so that two diodes always flow current in the circuit operation. Under the condition of low power and large current, the loss of the diode of the input rectifier bridge is particularly serious. In order to reduce or even eliminate the loss in the diode rectifier bridge, three-phase bridgeless PFC converter topologies based on a SEPIC circuit are proposed successively, and at present, two types, namely a totem-pole modular SEPIC type three-phase PFC converter and a bridgeless Dual SEPIC type three-phase PFC converter, are mainly used.
The totem-pole modular SEPIC type three-phase PFC converter topology can be regarded as three parallel single-phase totem-pole bridgeless SEPIC type PFC converters, and has three independent output ports. Considering the coupling problem of the three-phase non-isolated structure, three independent output terminals cannot be connected together. Meanwhile, each single-phase module of the converter has one input diode which works all the time, and the system efficiency is reduced. The bridgeless Dual SEPIC type three-phase PFC converter topology uses more semiconductor power devices, and for each phase of alternating current input, two groups of inductors and capacitors are adopted to respectively work on a positive half shaft and a negative half shaft of input voltage, so that the coupling problem caused by a non-isolated structure is solved, but the utilization rate of the devices is low, and the power density of a system is low.
In addition, due to the actual existence of the junction capacitor of the power switch tube, during the follow current period of the turn-off of the switch tube, the junction capacitor of the switch tube can resonate with the energy storage inductor, so that the next conducting signal of the switch tube is not equal to the current of the energy storage inductor when the filtering inductor is input temporarily, and therefore the input current of the three-phase bridgeless PFC converter based on the SEPIC circuit has current distortion under the control of the DCM with the fixed duty ratio.
Disclosure of Invention
The invention provides a three-phase bridgeless SEPIC type PFC converter, aiming at the problems of low utilization rate of topological components of the existing SEPIC type three-phase PFC converter and current distortion caused by junction capacitance of a power switch tube.
The invention discloses a three-phase bridgeless SEPIC type PFC converter which comprises three input filter inductors, three energy storage capacitors, three energy storage inductors, three groups of bidirectional switches, six switches and two output filter capacitors, wherein the six switches are divided into three groups of unidirectional switches, and each group of two switches is provided with a first input filter inductor and a second input filter inductor; the single-phase conversion circuit comprises an input filter inductor, an energy storage capacitor, an energy storage inductor, a group of bidirectional switches, a group of unidirectional switches and two output filter capacitors;
in the single-phase conversion circuit, each phase of input power supply is respectively connected with an input filter inductor, a group of bidirectional switches and an energy storage inductor in series in sequence, two ends of the bidirectional switch connected with the energy storage inductor in series are connected with an energy storage capacitor in parallel, the connection point of the bidirectional switch and the energy storage inductor is an M point, the connection point of the energy storage inductor and the energy storage capacitor is simultaneously connected with one end of two switches in the group of unidirectional switches, and the other ends of the group of unidirectional switches are X points respectively 1 And X 2 Two output filter capacitors are respectively connected in series with X 1 Point to point M and X 2 Between points and M points.
Preferably, the bidirectional switch is two reverse series power switching tubes, the reverse series power switching tubes comprise anti-parallel diodes and junction capacitors, and the PFC converter works in a critical conduction mode;
when a group of unidirectional switch currents of the A phase and zero passage occur, the bidirectional switch of the A phase is conducted, and the conduction time is prolonged
Then, the A-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch current of the B phase crosses zero, the bidirectional switch of the B phase is conducted for the conduction time
Then, the B-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch currents of the C phase and zero passage, the C phase bidirectional switch is conducted, and the conduction time is
Then, the C-phase bidirectional switch is turned off to complete a switching period;
v A 、v B 、v C representing instantaneous values of three-phase input voltage, V, of input power at power frequency dc Is representative of the output voltage of the PFC converter,
r A ＝r B ＝r C ，
r A 、r B 、r C representing A, B, C three-phase network-side equivalent input resistance, L 2 Representing the inductance value of the energy storage inductor.
The invention also provides a four-wire three-phase bridgeless SEPIC type PFC converter, wherein the neutral line of a three-phase input power supply is connected with the M point.
Preferably, the bidirectional switch is two reverse series power switching tubes, the reverse series power switching tubes comprise anti-parallel diodes and junction capacitors, and the PFC converter works in a critical conduction mode;
when a group of unidirectional switch currents of the A phase and zero passage occur, the bidirectional switch of the A phase is conducted, and the conduction time is prolonged
Then, the A-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch current of the B phase crosses zero, the bidirectional switch of the B phase is conducted, and the conduction time
Then, the B-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch current of the C phase crosses zero, the bidirectional switch of the C phase is conducted, and the conduction time
Then, the C-phase bidirectional switch is turned off to complete a switching period;
v A 、v B 、v C representing instantaneous values of three-phase input voltage, V, of input power at power frequency dc Is representative of the output voltage of the PFC converter,
r A ＝r B ＝r C ，r A 、r B 、r C representing A, B, C three-phase network-side equivalent input resistance, L 1 Representing the inductance value, L, of the filter inductor 2 Representing the inductance value of the energy storage inductor.
As a preference, the first and second liquid crystal compositions are,
alpha represents the current ripple coefficient, T A_min Indicating the lowest switching frequency, V rms Representing the effective value of three-phase voltage, P o Representing the PFC converter output power.
The invention has the advantages that diodes which work all the time do not exist at the input side in the topology, and compared with the existing topology, the number of semiconductor power devices, inductors and capacitors is optimal, and the utilization rate of components is higher. Meanwhile, aiming at the current distortion problem caused by the junction capacitance of the power switch tube, the critical conduction mode (CRM) control is adopted, the power factor correction of the input side is realized according to the conduction time control equation, the current distortion problem is effectively solved, the conduction loss of the converter can be further reduced, and the efficiency of the converter is effectively improved.
Drawings
Fig. 1 is a circuit diagram of a three-wire three-phase bridgeless SEPIC type PFC converter;
fig. 2 is a circuit diagram of a four-wire three-phase bridgeless SEPIC type PFC converter;
FIG. 3 is a diagram of a three-phase input voltage divided into different working intervals, wherein the ordinate v represents the three-phase input voltage, and the abscissa t represents the working time;
FIG. 4 shows the input voltage at[π/3,π/2]Three-wire three-phase bridgeless SEPIC type PFC converter in interval switches S in one switching period a1 、S b2 、S c2 Current, energy storage inductance L a2 、L b2 、L c2 Current and switch Q a1 、Q b2 、Q c2 A current waveform diagram;
fig. 5 is a working mode diagram of a three-wire three-phase bridgeless SEPIC PFC converter in an interval of [ pi/3, pi/2 ] of input voltages under different switching states, where fig. 5(a) is a working mode diagram of a working phase (1), fig. 5(b) is a working mode diagram of a working phase (2), fig. 5(c) is a working mode diagram of a working phase (3), fig. 5(d) is a working mode diagram of a working phase (4), and fig. 5(e) is a working mode diagram of a working phase (5); fig. 5(f) is an operation mode diagram of the operation phase (6); fig. 5(g) is an operation mode diagram of the operation phase (7);
fig. 6 is a block diagram of CRM control algorithm for a three-phase bridgeless SEPIC-type PFC converter;
FIG. 7 shows the A-phase switch S of a four-wire three-phase bridgeless SEPIC PFC converter under 4 different working modes in one switching period a1 Current, energy storage inductance L a2 Current and switch Q a1 、Q a2 A current waveform diagram;
FIG. 8 is a diagram of the operation mode of the A phase of the four-wire three-phase bridgeless SEPIC type PFC converter under different states, including the mode v in FIG. 8(a) A >0, bidirectional switch conduction mode, v in FIG. 8(b) A >0, bidirectional switch off mode, v in FIG. 8(c) A <0, conduction mode of the bidirectional switch, v in FIG. 8(d) A <0, a bidirectional switch turn-off mode;
FIG. 9 is a diagram of three-phase input voltage and current waveforms under the conditions of 110V/50Hz three-phase input and 270V/1500W output, wherein FIG. 9(a) is the input voltage and current waveforms of the three-wire three-phase bridgeless SEPIC type PFC converter of embodiment 1; fig. 9(b) shows input voltage and current waveforms of the four-wire three-phase bridgeless SEPIC type PFC converter of example 2.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
The three-phase bridgeless SEPIC type PFC converter of the embodiment comprises three input filter inductors, wherein the three input filter inductors are L respectively a1 、L b1 、L c1 Three small-capacity energy-storage capacitors, each being C a1 、C b1 、C c1 Three small inductance energy storage inductors, L respectively a2 、L b2 、L c2 Two output filter capacitors C dc1 、C dc2 Three sets of bidirectional switches, first set S a1 、S a2 (ii) a Second group S b1 、S b2 (ii) a Third group S c1 、S c2 Six switches Q a1 —Q c2 The switch can be selected according to the working mode of the circuit: the boosting mode adopts a diode/synchronous rectifier tube; the buck-boost mode uses a unidirectional current controllable switch with reverse blocking capability, such as a unidirectional current controllable switch IGBT with reverse blocking capability or a standard IGBT series diode without reverse blocking capability.
Wherein, the inductance values of the three input filter inductors are the same and are L 1 The capacitance values of the three small-capacity energy storage capacitors are the same and are C 1 The inductance of the three small inductance energy storage inductors is the same and is L 2 The capacitance values of the two output filter capacitors are the same and are C dc Each group of bidirectional switches is realized by adopting reverse series connection of switch tube switches, the actions are the same, and the bidirectional flow of energy can be realized.
The single-phase conversion circuit comprises an input filter inductor, an energy storage capacitor, an energy storage inductor, a group of bidirectional switches, a group of unidirectional switches and two output filter capacitors;
the circuit structure of the three-phase bridgeless SEPIC type PFC converter can be divided into a three-phase three-wire system and a three-phase four-wire system according to whether a neutral wire exists in a three-phase alternating-current power supply or not.
Example 1: as shown in fig. 1, in the three-wire three-phase bridgeless SEPIC type PFC converter of the present embodiment, in the a-phase single-phase conversion circuit, the a-phase input power source and the input filter inductor L are connected to each other a1 Two-way switch S a1 、S a2 Energy storage inductor L a2 Serially connected in sequence, a bidirectional switch S a1 、S a2 And energy storage inductor L a2 Two ends of the series are connected with an energy storage capacitor C in parallel a1 Two-way switch S a1 、S a2 And energy storage inductor L a2 The connection point of (A) is M point, and the energy storage inductor L a2 And an energy storage capacitor C a1 The connecting point is simultaneously connected with one end of two switches in a group of one-way switches, and the other end of the group of one-way switches is respectively X 1 And X 2 Two output filter capacitors C dc1 、C dc2 Are respectively connected in series at X 1 Point to point M and X 2 Between points and M points.
The quantity of semiconductor power device that this embodiment used is less, compares in 18 semiconductor power device of three switch bridgeless Dual SEPIC type three-phase PFC converter, 6 energy storage capacitor, 6 energy storage inductance, and the topology of this embodiment adopts 12 semiconductor power device, 3 energy storage capacitor, 3 energy storage inductance, and semiconductor power device quantity reduces, and inductance, electric capacity quantity halve, and the components and parts utilization ratio effectively improves, and system efficiency and power density also can promote.
The working condition and three-phase input voltage v of the three-phase bridgeless SEPIC type PFC converter of the embodiment A 、v B 、v C The waveform change condition of the three-way bidirectional switch and the control condition of the three-way bidirectional switch are related. According to the polarity relation of the three-phase input voltage, a power grid period is divided into 12 intervals, and the relation between the positive value and the negative value and the absolute value of the three-phase voltage in each interval is unchanged. In the interval [ pi/3, pi/2]For example, detailed analysisAnd (4) working process of the converter.
Before analyzing the operation principle of the PFC converter, the following explanation is made:
1) the PFC converter works in a critical conduction mode (CRM);
2) output filter capacitor C dc1 、C dc2 Sufficiently large that the partial voltages of the two capacitors are equal, i.e. v Cdc1 ＝v Cdc2 ＝V dc /2；
3) The power switch tube of the bidirectional switch comprises an anti-parallel diode and a junction capacitor;
4) the switching frequency is far higher than the frequency of the input alternating current power supply, and the switching period is T S Internally considering the three-phase input voltage as a fixed value V A 、V B 、V C The voltage of the energy storage capacitor is a constant value V a1 、V b1 、V c1 。
In the three-phase input voltage [ pi/3, pi/2 ] interval, according to the conduction condition of the three-way bidirectional switch, the converter has 7 working modes, the main current waveform of the circuit in one switching period in the [ pi/3, pi/2 ] interval is shown in fig. 4, and the corresponding working mode is shown in fig. 5.
Mode I: as shown in fig. 5(a), the three sets of bidirectional switches are all on at this stage. A-phase input filter inductor L a1 Forward charging, inductance L a1 The current rises linearly in the positive direction; B. c-phase input filter inductor L b1 、L c1 Reverse charging, inductance L b1 、L c1 The current rises linearly in the opposite direction. Energy storage inductor L a2 、L b2 、L c2 The voltages at both ends are respectively equal to the energy storage capacitor C a1 、C b1 、C c1 The voltage across, i.e. v La2 ＝V a1 、v Lb2 ＝V b1 、v Lc2 ＝V c1 . Energy storage capacitor C a1 、C b1 、C c1 Respectively to energy storage inductance L a2 、L b2 、L c2 Discharge, L a2 、L b2 、L c2 Energy is stored. At the same time, output filter capacitor C dc1 、C dc2 Collectively providing energy to the load.
Mode II: as shown in FIG. 5(B), the A, C-phase bidirectional switch is turned on, and the B-phase bidirectional switch is turned onThe bi-directional switch is turned off. A. C-phase input filter inductor L a1 、L c1 Linear charging; energy storage inductor L a2 、L c2 The voltages at the two ends are still respectively the voltage V of the energy storage capacitor a1 、V c1 Inductance L a2 、L c2 And (4) linear charging. The B-phase bidirectional switch is turned off, and the voltage at two ends of the bidirectional switch is clamped to be V b1 -V dc /2. Input filter inductance L b1 Discharging to the output side, and linearly reducing the current; energy storage inductor L b2 The reference direction of the voltage at two ends is opposite to the current, and the inductance L b2 Energy is also released to the output side. At the same time, switch Q b2 Lead to filter capacitor C dc2 And the load supplies energy, the current of which drops linearly from the peak value until the switch Q b2 The current drops to 0 and the B-phase bidirectional switch starts to conduct.
Mode III: as shown in fig. 5(c), the a-phase bidirectional switch is on, and the B, C-phase bidirectional switch is off. A-phase input filter inductor L a1 Energy storage inductor L a2 And (4) linear charging. B. The C-phase bidirectional switch is turned off, and the voltage clamp at the two ends of the B-phase bidirectional switch is V b1 -V dc Voltage clamping of two ends of/2, C-phase bidirectional switch is V c1 -V dc /2. Input filter inductance L b1 、L c1 Releasing energy to the output side. Energy storage inductor L b2 、L c2 The reference direction of the voltage at two ends is opposite to the current, and the inductance L b2 、L c2 Energy is also released to the output side. At the same time, switch Q b2 、Q c2 Lead to filter capacitor C dc2 And the load supplying energy up to the switch Q b2 、Q c2 The current drops to 0 and the B, C phase bidirectional switch begins to conduct.
Mode IV: as shown in fig. 5(d), the a-phase bidirectional switch is off, and the B, C-phase bidirectional switch is on. B. C-phase input filter inductor L b1 、L c1 Linear charging; energy storage inductor L b2 、L c2 The voltages at both ends are respectively the voltage V of the energy storage capacitor b1 、V c1 Inductance L b2 、L c2 And (4) linear charging. The A-phase bidirectional switch is turned off, and the voltage clamp at two ends of the bidirectional switch is V a1 +V dc /2. Input filter inductor L a1 Discharging to the output side, and linearly reducing the current; energy storage inductor L a2 The reference direction of the voltage at two ends is opposite to the current, and the inductance L a2 Energy is also released to the output side. At the same time, switch Q a1 Lead to filter capacitor C dc1 And the load supplies energy, the current of which drops linearly from the peak value until the switch Q a1 The current drops to 0 and the a-phase bidirectional switch begins to conduct.
Mode V: as shown in fig. 5(e), the A, C-phase bidirectional switch is turned off, and the B-phase bidirectional switch is turned on. The voltage at two ends of the A-phase bidirectional switch is clamped to be V a1 +V dc Voltage clamping of two ends of/2, C-phase bidirectional switch is V c1 -V dc /2. A-phase input filter inductor L a1 Energy storage inductor L a2 Releasing energy to the output side, switch Q a1 Lead to filter capacitor C dc1 And the load provides energy. B-phase input filter inductor L b1 Energy storage inductor L b2 And (4) linear charging. C-phase input filter inductor L c1 Energy storage inductor L c2 Releasing energy to the output side, switch Q c2 Lead to filter capacitor C dc2 And the load provides energy.
Mode VI: as shown in fig. 5(f), the A, B-phase bidirectional switch is turned off, and the C-phase bidirectional switch is turned on. The voltage at two ends of the A-phase bidirectional switch is clamped to be V a1 +V dc Voltage clamping of two ends of/2, B-phase bidirectional switch is V b1 -V dc /2. A-phase input filter inductor L a1 Energy storage inductor L a2 Releasing energy to the output side, switch Q a1 Lead to filter capacitor C dc1 And the load provides energy. B-phase input filter inductor L b1 Energy storage inductor L b2 Releasing energy to the output side, switch Q b2 Lead to filter capacitor C dc2 And the load provides energy. C-phase input filter inductor L c1 Energy storage inductor L c2 And (4) linear charging.
Mode VII: as shown in fig. 5(g), the three sets of bidirectional switches are all off at this stage. The voltage at two ends of the A-phase bidirectional switch is clamped to be V a1 +V dc Voltage clamping of two ends of/2, B-phase bidirectional switch is V b1 -V dc Voltage clamping of two ends of/2, C-phase bidirectional switch is V c1 -V dc /2. Three-way input filter inductor L a1 、L b1 、L c1 And an energy storage inductor L a2 、L b2 、L c2 Releasing energy to the output side while switching Q a1 、Q b2 、Q c2 All are conducted to the filter capacitors C dc1 、C dc2 、C dc2 And the load provides energy.
Through the analysis of the above 7 operation modes, it can be known that A, B, C three-phase operation is relatively independent, and the turn-on signal of A, B, C each phase bidirectional switch is from its own switch Q a1 、Q b2 、Q c2 A zero crossing detection signal of the current. When the switch Q a1 The A-phase bidirectional switch is turned on when the current is reduced to 0, and when the switch Q is turned on b1 The B-phase bidirectional switch is turned on when the current is reduced to 0, and when the switch Q is turned on c1 When the current is reduced to 0, the C-phase bidirectional switch is conducted.
According to the analysis of the working mode of the three-phase PFC converter, taking the A phase as an example, the switch Q is required to be switched on during the conduction period of the A-phase bidirectional switch for realizing the power factor correction function a2 And (6) turning off. During the conduction period of the bidirectional switch, the switch Q a2 Voltage at both ends is V A -V dc And/2, when the converter works in a boost mode, namely the output voltage is more than 2 times of the peak value of the single-phase input voltage, the switch Q a1 The voltage at both ends is negative, at this time, the switch Q a1 The power factor correction function can be realized by adopting a diode/synchronous rectifier tube. When the converter works in a buck-boost working mode, namely the output voltage is 2 times less than the peak value of the single-phase input voltage, the switch Q a2 The PFC function of the converter is realized by adopting a unidirectional current controllable switch with reverse blocking capability, such as a unidirectional current controllable switch IGBT with reverse blocking capability or a standard IGBT series diode without reverse blocking capability. When the standard IGBT without reverse blocking capability is adopted to be connected with the diode in series, the working frequency of the standard IGBT without reverse blocking capability is the frequency of the three-phase input power supply.
The average voltage in the period of the voltage switches at the two ends of the three-phase input filter inductor is 0, so that:
v A 、v B 、v C three-phase input voltage instantaneous values v of input power supply under power frequency AM 、v BM 、v CM Respectively representing instantaneous values, v, of the voltage between node A, B, C and point M at power frequency MN The instantaneous value of the voltage between the output capacitor midpoint M and the three-phase power supply midpoint N under the power frequency is represented;
three-phase AC voltage balance, v A +v B +v C When 0, this gives:
the formula (2) can be substituted for the formula (1):
this makes it possible to obtain:
taking into account the energy storage inductance L a2 、L b2 、L c2 The average voltage in the period of the two-end voltage switch is 0, and the energy storage capacitor C is arranged at power frequency a1 、C b1 、C c1 Instantaneous value v of the voltage across the terminals Ca1 、v Cb1 、v Cc1 Can be expressed as:
energy storage capacitor C a1 、C b1 、C c1 The voltages at the two ends are respectively equal to A, B, C three-phase voltages. Thus during the switching cycle there are:
through the analysis of the previous 7 working modes, the turn-off time of the bidirectional switch is the switch Q a1 、Q b2 、Q c2 The peak moment of the current. Considering L 1 >>L 2 Neglecting the change of current on each phase of input filter inductor, the switch Q a1 、Q b2 、Q c2 Current peak value i Qa_peak 、i Qb_peak 、i Qc_peak Can be expressed as:
in the formula (d) A 、T A Respectively, the A-phase bidirectional switch duty ratio and the switching period, d B 、T B Respectively B-phase bidirectional switch duty ratio and switching period, d C 、T C Respectively, the duty cycle and the switching period of the C-phase bidirectional switch.
Energy storage inductor L a2 、L b2 、L c2 The switching period of the voltage at two ends meets the volt-second balance, namely:
the Q switch in the switching period can be obtained according to the formula (7) and the formula (8) a1 、Q b2 、Q c2 Average value of current i Qa_avg 、i Qb_avg 、i Qc_avg ：
In other intervals of three-phase alternating voltage, the working condition of the converter is similar to [ pi/3, pi/2 ] intervals, and an expression of three-phase input current under CRM control is obtained according to the input-output power conservation condition under an ideal condition:
in the formula, T A_ON 、T B_ON 、T C_ON Respectively, the conduction time of the A, B, C three-phase bidirectional switch.
In order to realize the unit power factor correction of the three-phase input side, the conduction time of each-phase bidirectional switch control needs to meet the following requirements:
in the formula, r A 、r B 、r C A, B, C three-phase network side equivalent input resistances respectively, r is generated when three-phase voltage and power are balanced A ＝r B ＝r C 。
Order to
A modification of equation (11) can be obtained:
equation (12) is a CRM control equation of the proposed three-phase bridgeless SEPIC type PFC converter, and a structural block diagram of a control method is shown in fig. 6, where V is m Can be obtained by a voltage closed loop of the output voltage. The CRM control method based on the formula (12) comprises the steps of conducting at fixed time and controlling to be turned off, wherein a conducting signal depends on a zero-crossing detection signal of current sum of each phase switch, namely the conducting time of the phase A is i Qa1 +i Qa2 The B-phase conduction time is i Qb1 +i Qb2 C-phase conduction time is i Qc1 +i Qc2 Current and zero crossing time. The current sum is selected because the stage of each phase of input voltage being positive is that the upper switch works and the lower switch is turned off, the stage of each phase of input voltage being negative is that the lower switch works and the upper switch is turned off, and the zero-crossing detection of the current sum can omit the input electricityAnd (6) judging the pressure. Resetting the integrator and starting to couple V at the turn-on time of each phase bidirectional switch m And starting integration until the output of each phase of integrator meets the CRM control equation shown in the formula (12), turning over the comparator, turning off the bidirectional switch, and finishing one switching period. By adopting the CRM control method based on the formula (12), the three-phase PFC converter can work in a critical conduction state, the follow current stage is effectively avoided, and the problem that the input current is distorted due to the resonance of the bidirectional switch junction capacitor in the follow current stage is effectively solved.
According to equation (8), the three-phase PFC converter has a wider output gain, which can be expressed as:
when the input voltage of a certain phase is close to zero crossing, the duty ratio of the phase is larger; at the peak of the input voltage, the duty cycle of the phase is small. A wide range of variation of the output voltage can be achieved by closed loop regulation of the output voltage.
Example 2: as shown in fig. 2, in the four-wire system three-phase bridgeless SEPIC-type PFC converter of the present embodiment, in the a-phase single-phase conversion circuit, the a-phase input power source and the input filter inductor L are connected to each other a1 Two-way switch S a1 、S a2 Energy storage inductor L a2 Serially connected in sequence, a bidirectional switch S a1 、S a2 And energy storage inductor L a2 Two ends of the series are connected with an energy storage capacitor C in parallel a1 Two-way switch S a1 、S a2 And energy storage inductor L a2 The connection point of (A) is M point, and the energy storage inductor L a2 And an energy storage capacitor C a1 The connecting point is simultaneously connected with one end of two switches in a group of one-way switches, and the other end of the group of one-way switches is respectively X 1 And X 2 Two output filter capacitors C dc1 、C dc2 Are respectively connected in series at X 1 Point to point M and X 2 And the neutral line of the three-phase input power supply is connected with the point M. At the moment, the three-phase bridgeless SEPIC type PFC converter realizes decoupling on the circuit structure, and each phase of circuit works completely independently. Three-phase input voltage and power levelBalance, output current of each phase is I dc /3. Taking the phase a as an example, according to the positive and negative of the a-phase alternating-current voltage and the switching state of the bidirectional switch, the single-phase model of the CRM-controlled three-phase bridgeless SEPIC-type PFC converter has 4 different operation modes, the main current waveform of the circuit of the switching period is shown in fig. 7, and the corresponding operation mode is shown in fig. 8.
Modality I: as shown in FIG. 8(a), the phase v A >0, A phase bidirectional switch is conducted, and a filter inductor L is input in a switching period a1 Voltage at both ends is V A The inductor current rises linearly in the forward direction. Energy storage inductor L a2 The voltage at two ends is the voltage V of the energy storage capacitor a1 And an energy storage capacitor C a1 Energy storage inductor L through bidirectional switch a2 Discharging and energy-storing inductor L a2 The current rises linearly. At this time, the load is formed by an output filter capacitor C dc1 、C dc2 Providing energy.
Mode II: as shown in FIG. 8(b), this stage v A >0, the A-phase bidirectional switch is turned off, and the filter inductor L is input in the switching period a1 Voltage at both ends is V A -V a1 -V dc /2<0, the inductor current starts to decrease linearly. Energy storage inductor L a2 Filter capacitor C with two-terminal voltage as output dc1 Voltage, reference direction of voltage is opposite to current, energy storage inductance L a2 Energy is released to the output side, and the energy storage inductor L a2 The current decreases linearly. At this time, the switch Q a1 Is conducted to the filter capacitor C dc1 And the load supplies energy, the current of which drops linearly from the peak value until the switch Q a1 The current drops to 0 and the A-phase bidirectional switch is turned on.
Mode III: as shown in FIG. 8(c), this stage v A <0, A phase bidirectional switch is conducted, and a filter inductor L is input in a switching period a1 Voltage at both ends is V A The inductor current rises in an inverse linear fashion. Energy storage inductor L a2 The voltage at two ends is the voltage V of the energy storage capacitor a1 Energy storage capacitor C a1 Energy storage inductor L through bidirectional switch a2 Discharging and energy-storing inductor L a2 The current rises linearly. At this time, the load is formed by an output filter capacitor C dc1 、C dc2 Provide forEnergy.
Mode IV: as shown in FIG. 8(d), this stage v A <0, A phase bidirectional switch is turned off, and input filter inductor L a1 Voltage at both ends is V A -V a1 -V dc /2<0, the inductor current starts to decrease linearly. Energy storage inductor L a2 Filter capacitor C with two-terminal voltage as output dc2 Voltage, reference direction of voltage opposite to current, energy-storage inductance L a2 Energy is released to the output side, and the energy storage inductor L a2 The current decreases linearly. At this time, the switch Q a2 Is conducted to the filter capacitor C dc2 And the load supplies energy, the current of which drops linearly from the peak value until the switch Q a2 The current drops to 0 and the A-phase bidirectional switch is turned on.
From the foregoing analysis, the operation modes of the circuit are basically the same when the input voltage is positive or negative, and mainly include two modes of inductive charging and discharging. v. of A >0 and the bidirectional switch is turned off, switch Q a1 The current of (2) reaches a current peak value; v. of A <0 and the bidirectional switch is turned off, switch Q a2 Reaches a current peak value i Qa_max Can be expressed as:
thereby obtaining the switch Q in the switch period under the control of CRM a1 /Q a2 The average value of the current can be expressed as:
the input and output power is conserved under the power frequency condition, and the A-phase input current can be expressed as:
in the formula, T A_on The conduction time of the A-phase bidirectional switch is shown.
Each phase circuit of the three-phase bridgeless SEPIC type PFC converter under the three-phase four-wire system works completely independently, and the working process is basically the same. Thus obtaining the expression of three-phase input current wave under the control of three-phase four-wire system CRM:
in the formula, T A_on 、T B_on 、T C_on Respectively, the conduction time of the A, B, C three-phase bidirectional switch.
According to the input-side unit power factor correction requirement, the CRM control equation of the three-phase four-wire system can be expressed as follows:
in the formula (I), the compound is shown in the specification,
as can be seen by comparing equation (12) with equation (17), the CRM control equation for the three-wire system is substantially the same as that for the four-wire system, which illustrates that the proposed three-phase bridgeless SEPIC-type PFC converter does not have the problem of current coupling between three phases, and the converter can be controlled by using a single-phase control algorithm.
Combining the formula (8) and the formula (11), the switching period of the three-phase double-open switch can be obtained:
in the formula, P o For the output power, V, of a three-phase bridgeless SEPIC-type PFC converter rms The effective value of the three-phase voltage.
Under the control of CRM, the switching period of the three-phase bridgeless SEPIC type PFC converter is directly related to the working index of the circuit. As can be seen from the equation (18), when the input voltage, the output power, and the energy storage inductance are constant, the switching period is maximized at the peak of the three-phase input voltage and minimized near the zero crossing of the three-phase input voltage. When the parameters of the energy storage inductor in the embodiments 1 and 2 are designed, the variation range of the switching period needs to be determined, and the inductance of the energy storage inductor needs to be designed according to the conditions.
The three-phase input filter inductor is mainly designed by considering the current ripple of the three-phase input current. As can be known from the foregoing working principle, taking phase a as an example, the current ripple of the input filter inductor of phase a is:
under the condition of determining the size of the energy storage inductor and the current ripple factor alpha, the filter inductor L a1 Can be obtained from formula (20):
as can be seen from the above formula, the larger the input filter inductance value is, the smaller the input current ripple is. The design of circuit parameters is explained by taking a power frequency 50Hz three-phase input voltage of 110V, a constant voltage of 270V output and 1500W output as examples.
Design of minimum switching frequency T A_min At 50kHz, the inductance value of the energy storage inductor can be obtained according to equation (18) based on the given operating index:
taking the ripple coefficient alpha of the input current as 0.2, and determining the input filter inductance L according to the formula (20):
the power factor correction of the three-phase bridgeless SEPIC PFC converter with the above circuit parameters is shown in fig. 9, where fig. 9(a) is a three-phase three-wire system and fig. 9(b) is a three-phase four-wire system. According to simulation results, the input current of the CRM controlled down converter is sine wave, the input voltage waveform can be tracked in real time, and the power factor correction effect is good.
The method is applied to the fields of middle and small power such as LED driving power supplies, battery chargers and the like.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.
Claims (7)
1. A three-phase bridgeless SEPIC type PFC converter is characterized by comprising three input filter inductors, three energy storage capacitors, three energy storage inductors, three groups of bidirectional switches, six switches and two output filter capacitors, wherein the six switches are divided into three groups of unidirectional switches, and each group comprises two switches; the single-phase conversion circuit comprises an input filter inductor, an energy storage capacitor, an energy storage inductor, a group of bidirectional switches, a group of unidirectional switches and two output filter capacitors;
in the single-phase conversion circuit, each phase of input power supply is respectively connected with an input filter inductor, a group of bidirectional switches and an energy storage inductor in series in sequence, two ends of the bidirectional switch connected with the energy storage inductor in series are connected with an energy storage capacitor in parallel, the connecting point of the bidirectional switch and the energy storage inductor is M point, the connecting point of the energy storage inductor and the energy storage capacitor is simultaneously connected with one end of two switches in the group of unidirectional switches, and the other end of the group of unidirectional switches is X point respectively 1 And X 2 Two output filter capacitors are respectively connected in series with X 1 Point to point M and X 2 Between points and M points.
2. The three-phase bridgeless SEPIC-type PFC converter of claim 1, wherein the bidirectional switch is two reverse series power switching transistors, and the reverse series power switching transistors comprise an anti-parallel diode and a junction capacitor, the PFC converter operating in critical conduction mode;
when a group of unidirectional switch currents of the A phase and zero passage occur, the bidirectional switch of the A phase is conducted, and the conduction time is prolonged
Then, the A-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch current of the B phase crosses zero, the bidirectional switch of the B phase is conducted, and the conduction time
Then, the B-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch currents of the C phase and zero passage, the C phase bidirectional switch is conducted, and the conduction time is
Then, the C-phase bidirectional switch is turned off to complete a switching period;
v A 、v B 、v C representing instantaneous values of three-phase input voltage, V, of input power at power frequency dc Is representative of the output voltage of the PFC converter,
r A ＝r B ＝r C ，
r A 、r B 、r C representing A, B, C three-phase network-side equivalent input resistance, L 2 Representing the inductance value of the energy storage inductor.
3. A three-phase bridgeless SEPIC-type PFC converter according to claim 1, characterized in that the neutral line of the three-phase input power supply is connected to the point M.
4. The three-phase bridgeless SEPIC type PFC converter of claim 3, wherein the bidirectional switches are two inverse series power switching tubes including an inverse parallel diode and a junction capacitor, the PFC converter operating in critical conduction mode;
when a group of unidirectional switch currents of the A phase and zero passage occur, the bidirectional switch of the A phase is conducted, and the conduction time is prolonged
Then, the A-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch current of the B phase crosses zero, the bidirectional switch of the B phase is conducted, and the conduction time
Then, the B-phase bidirectional switch is turned off to complete a switching period;
when a group of unidirectional switch currents of the C phase and zero passage, the C phase bidirectional switch is conducted, and the conduction time is
Then, the C-phase bidirectional switch is turned off to complete a switching period;
v A 、v B 、v C representing instantaneous values of three-phase input voltage, V, of input power at power frequency dc Is representative of the output voltage of the PFC converter,
r A ＝r B ＝r C ，r A 、r B 、r C representing A, B, C three-phase network-side equivalent input resistance, L 1 Representing the inductance value, L, of the filter inductor 2 Representing the inductance value of the energy storage inductor.
5. The three-phase bridgeless SEPIC type PFC converter according to claim 2 or 4, characterized in that,
alpha represents the current ripple coefficient, T A_min Indicating the lowest switching frequency, V rms Representing the effective value of three-phase voltage, P o Representing the PFC converter output power.
6. The three-phase bridgeless SEPIC-type PFC converter according to claim 1, characterized in that said switches are unidirectional current controllable switches IGBT or standard IGBT series diodes.
7. The three-phase bridgeless SEPIC-type PFC converter according to claim 1, characterized in that said switches are diodes or synchronous rectifiers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210856098.5A CN115065230B (en) | 2022-07-19 | 2022-07-19 | Three-phase bridgeless SEPIC type PFC converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210856098.5A CN115065230B (en) | 2022-07-19 | 2022-07-19 | Three-phase bridgeless SEPIC type PFC converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115065230A true CN115065230A (en) | 2022-09-16 |
| CN115065230B CN115065230B (en) | 2023-05-30 |
Family
ID=83206727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210856098.5A Active CN115065230B (en) | 2022-07-19 | 2022-07-19 | Three-phase bridgeless SEPIC type PFC converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115065230B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116317528A (en) * | 2023-03-14 | 2023-06-23 | 哈尔滨工业大学 | Single-stage single-phase bridgeless voltage-multiplying CUK type PFC converter |
| CN117060708A (en) * | 2023-08-21 | 2023-11-14 | 哈尔滨工业大学 | Single-stage bridgeless PFC converter and control method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103515978A (en) * | 2013-03-21 | 2014-01-15 | 王林兵 | Efficient rectification-inversion-integrated energy feedback system |
| TWI566507B (en) * | 2016-03-17 | 2017-01-11 | Nat Chung-Shan Inst Of Science And Tech | Wind power generation charging circuit |
| CN107154639A (en) * | 2016-03-02 | 2017-09-12 | 西工大常熟研究院有限公司 | High efficiency commutation inversion integration energy feedback frequency converter |
| CN110739872A (en) * | 2019-12-05 | 2020-01-31 | 哈尔滨理工大学 | novel bidirectional high-transformation-ratio SWISS rectifier |
-
2022
- 2022-07-19 CN CN202210856098.5A patent/CN115065230B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103515978A (en) * | 2013-03-21 | 2014-01-15 | 王林兵 | Efficient rectification-inversion-integrated energy feedback system |
| CN107154639A (en) * | 2016-03-02 | 2017-09-12 | 西工大常熟研究院有限公司 | High efficiency commutation inversion integration energy feedback frequency converter |
| TWI566507B (en) * | 2016-03-17 | 2017-01-11 | Nat Chung-Shan Inst Of Science And Tech | Wind power generation charging circuit |
| CN110739872A (en) * | 2019-12-05 | 2020-01-31 | 哈尔滨理工大学 | novel bidirectional high-transformation-ratio SWISS rectifier |
Non-Patent Citations (1)
| Title |
|---|
| 刘广鹏: "三相SEPIC-PFC级联LCC-S无线充电变换器研究" * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116317528A (en) * | 2023-03-14 | 2023-06-23 | 哈尔滨工业大学 | Single-stage single-phase bridgeless voltage-multiplying CUK type PFC converter |
| CN116317528B (en) * | 2023-03-14 | 2024-04-05 | 哈尔滨工业大学 | Single-stage single-phase bridgeless voltage-multiplying CUK type PFC converter |
| CN117060708A (en) * | 2023-08-21 | 2023-11-14 | 哈尔滨工业大学 | Single-stage bridgeless PFC converter and control method |
| CN117060708B (en) * | 2023-08-21 | 2024-05-24 | 哈尔滨工业大学 | Single-stage bridgeless PFC converter and control method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115065230B (en) | 2023-05-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106936319B (en) | Isolated three-port bidirectional DC-DC converter | |
| CN115065230B (en) | Three-phase bridgeless SEPIC type PFC converter | |
| CN107070287A (en) | Electric energy router and electric energy router submodule | |
| CN108599564A (en) | A kind of capacitance voltage discontinuous mode capacitance series formula crisscross parallel Bcuk pfc converters | |
| CN112366962B (en) | Three-phase three-level rectifier based on three-winding isolation transformer | |
| CN110661413B (en) | Single-phase three-level power factor correction rectifier based on four symmetrical ports | |
| TW202143624A (en) | Multi-phase ac/dc converter | |
| CN211656002U (en) | Resonance bridgeless boost power factor correction AC-DC converter | |
| CN102299649A (en) | Power supply converter | |
| CN112865560B (en) | Multi-diode series back-to-back bridgeless three-level rectifier | |
| CN110086360A (en) | A kind of five level high efficiency rectifiers | |
| CN113746361A (en) | AC-DC power conversion system with high voltage gain | |
| CN116317528B (en) | Single-stage single-phase bridgeless voltage-multiplying CUK type PFC converter | |
| CN208862767U (en) | A kind of two-way mixed structure rectifier of modified | |
| CN115765515B (en) | Bidirectional-conversion three-phase buck-boost converter and control method thereof | |
| CN117013866A (en) | Single-stage wide-voltage isolation bidirectional AC/DC converter | |
| CN110289755A (en) | High power factor DCM Buck-Flyback pfc converter | |
| CN112865561B (en) | Diode clamping type back-to-back bridgeless three-level rectifier | |
| CN112865563B (en) | Three-port clamping type back-to-back bridgeless three-level rectifier | |
| CN113193768B (en) | Four-switch-tube series-type back-to-back three-level rectifier | |
| CN214315050U (en) | Wide-voltage hybrid PFC converter and switching power supply | |
| CN114665733A (en) | Multiplex bridge arm alternately-conducted multi-level converter and control method thereof | |
| CN113949269A (en) | Bridgeless buck-boost power factor correction converter and control system | |
| CN112072908A (en) | Six-inductor double-switch PFC topological structure for improving UPS power factor | |
| CN110707940A (en) | Improved SWISS rectifier based on phase-shifted full-bridge soft switch |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |