CN112271940A - Five-level rectifier with public high-voltage direct-current bus and control strategy - Google Patents

Five-level rectifier with public high-voltage direct-current bus and control strategy Download PDF

Info

Publication number
CN112271940A
CN112271940A CN202011244123.1A CN202011244123A CN112271940A CN 112271940 A CN112271940 A CN 112271940A CN 202011244123 A CN202011244123 A CN 202011244123A CN 112271940 A CN112271940 A CN 112271940A
Authority
CN
China
Prior art keywords
phase
signal
current
switching device
output
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.)
Pending
Application number
CN202011244123.1A
Other languages
Chinese (zh)
Inventor
王聪
程红
赵志浩
陶艳梅
杨道宽
袁巍
邹甲
卢其威
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China University of Mining and Technology Beijing CUMTB
Original Assignee
China University of Mining and Technology Beijing CUMTB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by China University of Mining and Technology Beijing CUMTB filed Critical China University of Mining and Technology Beijing CUMTB
Priority to CN202011244123.1A priority Critical patent/CN112271940A/en
Publication of CN112271940A publication Critical patent/CN112271940A/en
Pending legal-status Critical Current

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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/2173—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a biphase or polyphase circuit arrangement
    • 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
    • H02M1/4216—Arrangements for improving power factor of AC input operating from a three-phase input voltage
    • 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

Abstract

The invention discloses a five-level rectifier with a public high-voltage direct-current bus and a control strategy, and belongs to an AC/DC conversion technology and a control technology thereof. The converter provides various main power circuits for forming a pair of common high-voltage direct-current buses, greatly reduces the voltage stress of a power switch tube, and overcomes the defect that the traditional rectifier cannot generate high direct-current bus voltage due to the limitation of the voltage stress of the power switch tube. The rectifier and the control strategy balance the voltage of each series capacitor at the output side, can keep normal work even under the condition of unbalanced voltage of a three-phase power grid, do not need to use the isolation of a power frequency phase-shifting transformer which is huge, heavy and complex in wiring, greatly simplify the topology of a main power circuit, reduce the number of power switching devices, improve the working efficiency of a system, have small volume, light weight, low cost and simple control, and have important application value in the fields of medium-high voltage direct current transmission, high-power medium-high voltage frequency converters and the like.

Description

Five-level rectifier with public high-voltage direct-current bus and control strategy
Technical Field
The invention belongs to the technical field of medium-high voltage variable frequency speed regulation, and particularly relates to a five-level rectifier with a public high-voltage direct current bus and a system implementation scheme of a control strategy.
Background
In recent years, Multilevel converters (Multilevel converters) have been successfully applied in the fields of high-voltage high-power frequency conversion speed regulation, active power filtering, high-voltage direct current (HVDC) transmission, reactive power compensation of power systems and the like. The basic circuit topologies of multilevel converters can be roughly classified into a clamping type and a cell cascade type. Diode-clamped three-level medium-high voltage inverters manufactured by siemens corporation or ABB corporation and cascaded H-bridge medium-high voltage inverters manufactured by robinkon corporation or rituximab corporation, which are widely used in the industry at present, are typical representatives of the two types of products. In any of the two types of medium-high voltage frequency converters, in order to implement high-voltage power conversion by using low-voltage-resistant power electronic devices, an industrial frequency phase-shifting transformer with large volume, complex wiring and high price is required to be used at the input side of the rectifier to realize electrical isolation. This limits their use in many industrial applications.
The cascading multilevel converter without the power frequency transformer has attracted wide attention in the technical field of power electronics in recent years, and is considered to be an ideal implementation scheme of an intelligent power grid interface or a new generation medium-high voltage frequency converter which is suitable for a new energy power generation system to access and meets the distributed power generation requirement. The converter uses a high-frequency transformer to replace a power frequency phase-shifting transformer in the traditional cascade converter to realize electrical isolation, and when the converter is used for bidirectional power transmission, a cascade full-control H bridge multi-level power converter structure is adopted on a rectifying side. When the power converter is used for unidirectional power transmission, a unidirectional cascade multilevel power converter structure (comprising a cascade diode + Boost rectifying circuit, a cascade bridgeless rectifying circuit, a cascade VIENNA rectifying circuit and the like) is adopted at the rectifying side. Compared with the traditional rectifier stage of a medium-high voltage frequency converter, the implementation scheme of the rectifier stage of the converter cancels a power frequency phase-shifting transformer which is large in size, complex in wiring and high in price, so that the size, the weight and the manufacturing cost of a system are effectively reduced. However, such converters also have significant drawbacks, mainly represented by: each phase of N cascade rectifier modules can generate N groups of direct current output ends, and the direct current output ends of the N groups of rectifier modules cannot be directly connected in series to form a pair of common high-voltage direct current output buses because the input ends are not isolated, so that the N groups of rectifier modules cannot be directly used for high-voltage direct current transmission and cannot be directly connected with a multi-level inverter circuit to be used for medium-high voltage frequency conversion speed regulation. In order to realize a common high-voltage direct-current output bus or realize flexible control of N groups of rectified output direct-current voltages, N groups of cascaded rectification modules are necessarily connected with N high-frequency isolation DC-DC conversion modules in sequence, so that the complexity of the topological structure and the control mode of the whole system is increased, and the working efficiency is reduced.
Disclosure of Invention
The invention aims to overcome the defects and provides a novel five-level unit power factor rectifier implementation scheme with a common high-voltage direct-current bus, compared with the rectifier stage of the traditional high-voltage inverter, the novel five-level rectifier provided by the invention does not need to use a power frequency phase-shifting transformer at the input end, can use a low-voltage-resistant power switching tube to finish high-power unit power factor rectification conversion under high voltage, and compared with a multi-level converter without a power frequency transformer, the novel five-level rectifier provided by the invention can form a pair of common high-voltage direct-current buses at the direct-current side, and can flexibly realize balance control of capacitance and voltage at the output side The high-power electronic transformer, the high-power medium-high voltage AC-DC-AC frequency converter and other fields have important application value.
In order to achieve the purpose, the invention provides a five-level rectifier with a common high-voltage direct-current bus, which comprises a main power circuit, wherein the main power circuit comprises a high-frequency filter and a single-phase diodeRectifier bridge, boost inductance L and first modular unit (A), its characterized in that: the first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switchDevice S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The first terminal (a) of the single-phase diode rectifier bridge is connected with one end of the boost inductor L, the other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, and the alternating current input end of the single-phase diode rectifier bridge is connected into an alternating current power grid in series through the high-frequency filter.
In order to achieve the purpose, the three-phase parallel rectifier formed by the five-level rectifier with the common high-voltage direct-current bus comprises a three-phase main power circuit, and is characterized in that: the three-phase main power circuit comprises three high-frequency filters and three second module units (B), wherein each second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit (A), and each first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And the second terminal (f) of (a) and the quick returnComplex diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with a rectification output positive end of the single-phase diode rectifier bridge, a direct current output positive end (g) of each phase of the second module unit (B) is connected, a direct current output negative end (h) of each phase of the second module unit (B) is connected, 2 residual alternating current input ends of the second module unit (B) of each phase are connected, the first alternating current input ends of the three phases of the second module unit (B) form a group of connection ends, the second alternating current input ends of the three phases of the second module unit (B) form another group of connection ends, one group of connection ends are connected to a common neutral point, the other group of connection ends are respectively connected with the three high-frequency filters in series and connected into a three-phase power grid to form a three-phase parallel connection.
In order to achieve the purpose, the three-phase star connection rectifier formed by the five-level rectifier with the common high-voltage direct-current bus comprises a three-phase main power circuit, and is characterized in that: the three-phase main power circuit comprises three high-frequency filters and three second module units (B), wherein each second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit(A) Said first modular unit (A) comprising four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diodePipe D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of the second module unit (B) of each phase are arranged, the first alternating current input ends of the three-phase second module unit (B) form a group of wiring ends, the second alternating current input ends of the three-phase second module unit (B) form another group of wiring ends, one group of wiring ends are connected to a common neutral point, and the other group of wiring ends are respectively connected with the three high-frequency filters in series to form a three-phase power grid to form star connection.
In order to achieve the purpose, the invention provides a three-phase angle connection rectifier formed by a five-level rectifier with a common high-voltage direct-current bus, which comprises a three-phase main power circuit and is characterized in that: the three-phase main power circuit comprises three high-frequency filters and three second module units (B), wherein each second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit (A), and each first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switchOff device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of the second module unit (B) of each phase are arranged, the first alternating current input ends of the three phases of the second module unit (B) form a group of wiring ends, the second alternating current input ends of the three phases of the second module unit (B) form another group of wiring ends, one group of wiring ends are connected to the input end of a three-phase power grid through three high-frequency filters respectively, and the other group of wiring ends are sequentially connected to the input end of the next phase in the three-phase power grid to form an angular connection.
In order to achieve the purpose, the three-phase double-star connection rectifier formed by the five-level rectifier with the common high-voltage direct-current bus comprises a three-phase main power circuit, and is characterized in that: the three-phase main power circuit comprises three high-frequency filters and six bridge arm inductorsThe direct-current capacitor and the six second module units (B) form two groups of star-shaped connections in butt joint, in each group of star-shaped connections, the second module units (B) comprise single-phase diode rectifier bridges, boost inductors L and first module units (A), and the first module units (A) comprise four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathodeSaid fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, the second module unit (B) of each phase has 2 residual AC input ends, the first AC input ends of the three-phase second module units (B) form a group of wiring ends, the second AC input ends of the three-phase second module units (B) form another group of wiring ends, one group of wiring ends is connected to a common neutral point, the other group of wiring ends are respectively connected with one ends of three bridge arm inductors, the other ends of the two bridge arm inductors on each phase of bridge arm are respectively connected and are respectively connected to the input end of a three-phase power grid through one of the three high-frequency filters, and simultaneously, the common neutral point in the first group of star connection and the common neutral point in the second group of star connection are respectively connected with the two ends of the DC capacitor, forming a double star connection.
In order to achieve the above object, the present invention provides a five-level rectifier with a common high-voltage dc bus and a control strategy, wherein the control strategy of the five-level rectifier with the common high-voltage dc bus comprises the following steps:
(1) sampling the output side direct current voltage of a five-level rectifier with a common high-voltage direct current bus to obtain two output side direct current voltage signals Uo1、Uo2；
(2) Calculating two output side direct current voltage signals U in the step (1) by using the following formulao1、Uo2Average value of Uo，
Figure BDA0002769363450000041
(3) Will step withU in step (2)oWith a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulatord；
(4) Two output side direct current voltage signals U in the step (1)o1、Uo2Respectively associated with a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulator1、I2；
(5) The amplitude I of the direct current signal in the step (4) is measured1、I2Respectively corresponding to the amplitude I of the DC current signal in the step (3)dAdding the obtained DC current to obtain a given signal amplitude I1 *、I2 *Setting the DC current to a signal amplitude I1 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik1 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I1 *Multiplying to generate a given current comparison signal ig1 *Setting the DC current to a signal amplitude I2 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik2 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I2 *Multiplying to generate a given current comparison signal ig2 *；
(6) Sampling three-phase power grid voltage to obtain an input side alternating voltage signal UA，UB，UCCalculating U by using the following formulaAm、UAn，
Figure BDA0002769363450000042
Calculating the negative sequence component U of the AC voltage signal at the input side of the A phase by using the following formulaAf，
UAf＝UAm+UAn
Calculate the phase A required injection using the following equationNegative sequence component U ofAz，
Figure BDA0002769363450000043
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Average value of (d); sampling three-phase power grid current to obtain an input side alternating current signal IA，IB，ICCalculating a comparison signal i of the A feedback current by using the following formulaA；
iA＝|IA|+UAz
(7) Comparing the current given in step (5) with a signal ik1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA1PWM signal PWM ofA1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA2PWM signal PWM ofA2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA3PWM signal PWM ofA3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA4PWM signal PWM ofA4；
(8) Calculate U using the equationBm、UBn，
Figure BDA0002769363450000051
In the formula of UA，UB，UCFor the input side AC voltage signal in step (6), the following equation is usedCalculating negative sequence component U of AC voltage signal at input side of B phaseBf，
UBf＝UBm+UBn
Calculating the negative sequence component U to be injected in the B phase by using the following formulaBz，
Figure BDA0002769363450000052
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Using the following formula to calculate a comparison signal i of B feedback currentB，
iB＝|IB|+UBz
In the formula IBThe input side alternating current signal in the step (6);
(9) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of current opposite to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB1PWM signal PWM ofB1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB2PWM signal PWM ofB2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB3PWM signal PWM ofB3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB4PWM signal PWM ofB4；
(10) Calculate U using the equationCm、UCn，
Figure BDA0002769363450000053
In the formula of UA，UB，UCCalculating the negative sequence component U of the C-phase input side AC voltage signal for the input side AC voltage signal in the step (6) by using the following formulaCf，
UCf＝UCm+UCn
Calculating the negative sequence component U to be injected in the C phase by using the following formulaCz，
Figure BDA0002769363450000054
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Is calculated using the following formulaC，
iC＝|IC|+UCz
In the formula ICThe input side alternating current signal in the step (6);
(11) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of a current opposite to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC1PWM signal PWM ofC1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC2PWM signal PWM ofC2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC3PWM signal PWM ofC3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC4PWM signal PWM ofC4；
(12) PWM in the step (7)A1、PWMA2、PWMA3、PWMA4PWM in step (9)B1、PWMB2、PWMB3、PWMB4PWM in step (11)C1、PWMC2、PWMC3、PWMC4And the three-phase current is sent to a corresponding switch device, so that active power factor correction is realized, the input current is sinusoidal, and under the condition of unbalanced network voltage, the balance control of the output direct current capacitor voltage is realized, so that the three-phase input current is balanced.
The five-level rectifier with the public high-voltage direct-current bus and the control strategy have the advantages and positive effects that: compared with the traditional rectifier of a medium-high voltage frequency converter, the five-level rectifier with the public high-voltage direct current bus provided by the invention does not need to use a power frequency phase-shifting transformer at the input end, and can use a low-voltage-resistant power switching tube to finish high-power unit power factor rectification conversion under high voltage. The five-level rectifier provided by the invention can form a pair of common high-voltage direct-current buses on the direct-current side when single-phase input is carried out, can form a pair of uniform common high-voltage direct-current buses on the direct-current side when three-phase input is carried out, can form three pairs of independent common high-voltage direct-current buses on the direct-current sides output by the three-phase rectifiers respectively, and can flexibly realize balance control on the capacitor voltage on the output side of the rectifier module. The five-level rectifier main power circuit provided by the invention has the advantages of simple topological structure, high system working efficiency, small volume, light weight and low cost, and has important application value in the fields of High Voltage Direct Current (HVDC), high power electronic transformers, high power medium and high voltage alternating current-direct current-alternating current frequency converters and the like.
The invention is further described below with reference to the accompanying drawings.
Drawings
FIG. 1 is a circuit diagram of a first modular unit (A) of a five level rectifier and control strategy with a common high voltage DC bus according to the present invention;
FIG. 2 is a circuit diagram of a second modular unit (B) of a five level rectifier and control strategy with a common high voltage DC bus according to the present invention;
FIG. 3 is a circuit diagram of a five level rectifier with a common high voltage DC bus and a three phase parallel rectifier control strategy according to the present invention;
FIG. 4 is a circuit diagram of a five-level rectifier with a common high voltage DC bus and a three-phase star-connected rectifier with a control strategy according to the present invention;
FIG. 5 is a circuit diagram of a five-level rectifier with a common high voltage DC bus and a three-phase angle-connected rectifier control strategy according to the present invention;
FIG. 6 is a circuit diagram of a three-phase dual-star rectifier with a five-level rectifier and control strategy for a common high voltage DC bus according to the present invention;
FIG. 7 is a schematic diagram of an A-phase control strategy for a five-level rectifier and control strategy with a common high voltage DC bus according to the present invention;
FIG. 8 is a schematic diagram of a B-phase control strategy for a five-level rectifier and control strategy with a common high voltage DC bus according to the present invention;
FIG. 9 is a schematic diagram of a C-phase control strategy for a five-level rectifier and control strategy with a common high voltage DC bus according to the present invention;
FIG. 10 is a three phase input current waveform for a three phase parallel rectifier formed by a five level rectifier having a common high voltage DC bus in accordance with the present invention;
FIG. 11 is a graph of two DC capacitor voltage waveforms and the total output DC voltage waveform of a three phase parallel rectifier formed by a five level rectifier having a common high voltage DC bus according to the present invention;
FIG. 12 is an input side five level voltage waveform of a three phase parallel rectifier formed by a five level rectifier with a common high voltage DC bus according to the present invention;
best mode for carrying out the invention
The embodiments and the working principle of the present invention will be further described with reference to the accompanying drawings:
referring to fig. 1 and 2, a five-level rectifier with a common high voltage dc bus includes a main power circuit including a high frequency filter, a single phase diode rectifier bridge, a boostAn inductance L and a first modular unit (A) comprising four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Switching device S1First terminal (a) of and fast recovery diode D1Is connected with the anode of the fast recovery diode D1Cathode and fast recovery diode D2Is connected with the anode of the fast recovery diode D2And an output DC capacitor C connected in parallel3And a load resistance R1Is connected with the first terminal (m), and an output direct current capacitor C is connected in parallel3And a load resistance R1With a second terminal (n) connected in parallel with an output dc capacitor C4And a load resistance R2Is connected to the first terminal (m), the switching device S1And the second terminal (b) of the switching device S2First terminal (a) and flying capacitor C1Is connected to the first terminal (e) of the flying capacitor C1Second terminal (f) of and fast recovery diode D2Is connected to the anode of the switching device S2And the second terminal (b) of the switching device S3And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the first terminal (m), the switching device S3And the second terminal (b) of the switching device S4First terminal (a) and flying capacitor C2Is connected to the first terminal (e) of the flying capacitor C2Second terminal (f) of and fast recovery diode D3Anode and fast recovery diode D4Is connected to the cathode of a fast recovery diode D4And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the second terminal (n), the switching device S4Second terminal (b) of and fast recovery diode D3Is connected with the negative end of the rectification output of the single-phase diode rectifier bridge, and a switching device S1Is connected to one end of a boost inductor LThe other end of the voltage inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, and the alternating current input end of the single-phase diode rectifier bridge is connected in series with an alternating current power grid through the high-frequency filter.
Referring to fig. 1, 2 and 3, a three-phase parallel rectifier composed of a five-level rectifier having a common high voltage dc bus includes a three-phase main power circuit including three high frequency filters and three second module units (B) including a single-phase diode rectifier bridge, a boost inductor L and a first module unit (a) including four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Switching device S1First terminal (a) of and fast recovery diode D1Is connected with the anode of the fast recovery diode D1Cathode and fast recovery diode D2Is connected with the anode of the fast recovery diode D2And an output DC capacitor C connected in parallel3And a load resistance R1Is connected with the first terminal (m), and an output direct current capacitor C is connected in parallel3And a load resistance R1With a second terminal (n) connected in parallel with an output dc capacitor C4And a load resistance R2Is connected to the first terminal (m), the switching device S1And the second terminal (b) of the switching device S2First terminal (a) and flying capacitor C1Is connected to the first terminal (e) of the flying capacitor C1Second terminal (f) of and fast recovery diode D2Is connected to the anode of the switching device S2And the second terminal (b) of the switching device S3And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the first terminal (m), the switching device S3And the second terminal (b) of the switching device S4First terminal (a) and flying capacitor C2Is connected to the first terminal (e) of the flying capacitor C2Second terminal (f) of and fast recovery diode D3Anode and fast recovery diode D4Is connected to the cathode of a fast recovery diode D4And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the second terminal (n), the switching device S4Second terminal (b) of and fast recovery diode D3Is connected with the negative end of the rectification output of the single-phase diode rectifier bridge, and a switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, the positive end (g) of the direct current output of each phase of the second module unit (B) is connected, the negative end (h) of the direct current output of each phase of the second module unit (B) is connected, 2 residual alternating current input ends of each phase of the second module unit (B), the first alternating current input ends of the three-phase second module unit (B) form a group of wiring ends, the second alternating current input ends of the three-phase second module unit (B) form another group of wiring ends, one group of wiring ends are connected to a common neutral point, the other group of wiring ends are respectively connected with three high-frequency filters in series and are connected into a three-phase power grid to form three-phase parallel connection.
Referring to fig. 1, 2 and 4, a three-phase star rectifier composed of a five-level rectifier with a common high-voltage direct-current bus comprises a three-phase main power circuit including three high-frequency filters and three second module units (B) including a single-phase diode rectifier bridge, a boost inductor L and a first module unit (a) including four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Switching device S1First terminal (a) of and fast recovery diode D1Is connected with the anode of the fast recovery diode D1Cathode and fast recovery diode D2Is connected with the anode of the fast recovery diode D2And an output DC capacitor C connected in parallel3And a load resistance R1Is connected with the first terminal (m), and an output direct current capacitor C is connected in parallel3And a load resistance R1With a second terminal (n) connected in parallel with an output dc capacitor C4And a load resistance R2Is connected to the first terminal (m), the switching device S1And the second terminal (b) of the switching device S2First terminal (a) and flying capacitor C1Is connected to the first terminal (e) of the flying capacitor C1Second terminal (f) of and fast recovery diode D2Is connected to the anode of the switching device S2And the second terminal (b) of the switching device S3And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the first terminal (m), the switching device S3And the second terminal (b) of the switching device S4First terminal (a) and flying capacitor C2Is connected to the first terminal (e) of the flying capacitor C2Second terminal (f) of and fast recovery diode D3Anode and fast recovery diode D4Is connected to the cathode of a fast recovery diode D4And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the second terminal (n), the switching device S4Second terminal (b) of and fast recovery diode D3Is connected with the negative end of the rectification output of the single-phase diode rectifier bridge, and a switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of each phase of the second module unit (B) are arranged, the first alternating current input ends of the three-phase second module unit (B) form a group of wiring ends, the second alternating current input ends of the three-phase second module unit (B) form another group of wiring ends, one group of wiring ends are connected to a common neutral point, the other group of wiring ends are respectively connected with three high-frequency filters in series and connected into a three-phase power grid to form star connection.
Referring to fig. 1, 2 and 5, a three-phase angle rectifier formed by a five-level rectifier with a common high-voltage direct-current bus comprises a three-phase main power circuit which comprisesThree high-frequency filters and three second modular units (B) comprising a single-phase diode rectifier bridge, a boost inductor L and a first modular unit (A) comprising four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Switching device S1First terminal (a) of and fast recovery diode D1Is connected with the anode of the fast recovery diode D1Cathode and fast recovery diode D2Is connected with the anode of the fast recovery diode D2And an output DC capacitor C connected in parallel3And a load resistance R1Is connected with the first terminal (m), and an output direct current capacitor C is connected in parallel3And a load resistance R1With a second terminal (n) connected in parallel with an output dc capacitor C4And a load resistance R2Is connected to the first terminal (m), the switching device S1And the second terminal (b) of the switching device S2First terminal (a) and flying capacitor C1Is connected to the first terminal (e) of the flying capacitor C1Second terminal (f) of and fast recovery diode D2Is connected to the anode of the switching device S2And the second terminal (b) of the switching device S3And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the first terminal (m), the switching device S3And the second terminal (b) of the switching device S4First terminal (a) and flying capacitor C2Is connected to the first terminal (e) of the flying capacitor C2Second terminal (f) of and fast recovery diode D3Anode and fast recovery diode D4Is connected to the cathode of a fast recovery diode D4And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the second terminal (n), the switching device S4Second terminal (b) of and fast recovery diode D3Cathode and single-phase diode rectifier bridgeIs connected with the negative end of the rectification output, and a switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of each phase of the second module unit (B) are arranged, the first alternating current input ends of the three-phase second module unit (B) form a group of wiring ends, the second alternating current input ends of the three-phase second module unit (B) form another group of wiring ends, one group of wiring ends are connected to the input end of the three-phase power grid through three high-frequency filters respectively, and the other group of wiring ends are sequentially connected to the input end of the next phase in the three-phase power grid to form an angular connection.
Referring to fig. 1, 2 and 6, a three-phase double-star rectifier formed by a five-level rectifier with a common high-voltage direct-current bus comprises a three-phase main power circuit, wherein the three-phase main power circuit comprises three high-frequency filters, six bridge arm inductors, a direct-current capacitor and six second module units (B), the six second module units (B) form two groups of star-shaped connections in butt joint, in each group of star-shaped connections, the second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit (a), and the first module unit (a) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Switching device S1First terminal (a) of and fast recovery diode D1Is connected with the anode of the fast recovery diode D1Cathode and fast recovery diode D2Is connected with the anode of the fast recovery diode D2And an output DC capacitor C connected in parallel3And a load resistance R1Is connected with the first terminal (m), and an output direct current capacitor C is connected in parallel3And a load resistance R1With a second terminal (n) connected in parallel with an output dc capacitor C4And a load resistance R2Is connected to the first terminal (m), the switching device S1And the second terminal (b) of the switching device S2First wiring ofTerminal (a) and flying capacitor C1Is connected to the first terminal (e) of the flying capacitor C1Second terminal (f) of and fast recovery diode D2Is connected to the anode of the switching device S2And the second terminal (b) of the switching device S3And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the first terminal (m), the switching device S3And the second terminal (b) of the switching device S4First terminal (a) and flying capacitor C2Is connected to the first terminal (e) of the flying capacitor C2Second terminal (f) of and fast recovery diode D3Anode and fast recovery diode D4Is connected to the cathode of a fast recovery diode D4And an output DC capacitor C connected in parallel4And a load resistance R2Is connected to the second terminal (n), the switching device S4Second terminal (b) of and fast recovery diode D3Is connected with the negative end of the rectification output of the single-phase diode rectifier bridge, and a switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of the second module unit (B) of each phase are arranged, the first alternating current input ends of the three-phase second module unit (B) form a group of connection ends, the second alternating current input ends of the three-phase second module unit (B) form another group of connection ends, one group of the terminals is connected to a common neutral point, the other group of the terminals is respectively connected with one end of each of the three bridge arm inductors, the other ends of the two bridge arm inductors on each phase of bridge arm are respectively connected and are respectively connected to the input end of a three-phase power grid through one of three high-frequency filters, meanwhile, a common neutral point in the first group of star connection and a common neutral point in the second group of star connection are respectively connected with two ends of the direct current capacitor to form double star connection.
Referring to fig. 1, 2, 3, 4, 5, 6, 7 and 8, a control strategy for a five-level rectifier with a common high-voltage dc bus comprises the following steps:
(1) for output side direct current of five-level rectifier with common high-voltage direct current busThe voltage is sampled to obtain two output side direct current voltage signals Uo1、Uo2；
(2) Calculating two output side direct current voltage signals U in the step (1) by using the following formulao1、Uo2Average value of Uo，
Figure BDA0002769363450000091
(3) Mixing U in step (2)oWith a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulatord；
(4) Two output side direct current voltage signals U in the step (1)o1、Uo2Respectively associated with a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulator1、I2；
(5) The amplitude I of the direct current signal in the step (4) is measured1、I2Respectively corresponding to the amplitude I of the DC current signal in the step (3)dAdding the obtained DC current to obtain a given signal amplitude I1 *、I2 *Setting the DC current to a signal amplitude I1 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik1 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I1 *Multiplying to generate a given current comparison signal ig1 *Setting the DC current to a signal amplitude I2 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik2 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I2 *Multiplying to generate a given current comparison signal ig2 *；
(6) Sampling three-phase power grid voltage to obtain an input side alternating voltage signal UA，UB，UCCalculated using the following equationUAm、UAn，
Figure BDA0002769363450000092
Calculating the negative sequence component U of the AC voltage signal at the input side of the A phase by using the following formulaAf，
UAf＝UAm+UAn
Calculating the negative sequence component U to be injected in the phase A by using the following formulaAz，
Figure BDA0002769363450000093
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Average value of (d); sampling three-phase power grid current to obtain an input side alternating current signal IA，IB，ICCalculating a comparison signal i of the A feedback current by using the following formulaA；
iA＝|IA|+UAz
(7) Comparing the current given in step (5) with a signal ik1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA1PWM signal PWM ofA1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA2PWM signal PWM ofA2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA3PWM signal PWM ofA3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to A in step (6)ASending into a comparator for comparison to obtainA-phase switching device SA4PWM signal PWM ofA4；
(8) Calculate U using the equationBm、UBn，
Figure BDA0002769363450000094
In the formula of UA，UB，UCCalculating the negative sequence component U of the B-phase input side AC voltage signal for the input side AC voltage signal in the step (6) by using the following formulaBf，
UBf＝UBm+UBn
Calculating the negative sequence component U to be injected in the B phase by using the following formulaBz，
Figure BDA0002769363450000101
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Using the following formula to calculate a comparison signal i of B feedback currentB，
iB＝|IB|+UBz
In the formula IBThe input side alternating current signal in the step (6);
(9) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of current opposite to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB1PWM signal PWM ofB1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB2PWM signal PWM ofB2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switchDevice SB3PWM signal PWM ofB3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB4PWM signal PWM ofB4；
(10) Calculate U using the equationCm、UCn，
Figure BDA0002769363450000102
In the formula of UA，UB，UCCalculating the negative sequence component U of the C-phase input side AC voltage signal for the input side AC voltage signal in the step (6) by using the following formulaCf，
UCf＝UCm+UCn
Calculating the negative sequence component U to be injected in the C phase by using the following formulaCz，
Figure BDA0002769363450000103
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Is calculated using the following formulaC，
iC＝|IC|+UCz
In the formula ICThe input side alternating current signal in the step (6);
(11) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of a current opposite to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC1PWM signal PWM ofC1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching deviceSC2PWM signal PWM ofC2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC3PWM signal PWM ofC3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC4PWM signal PWM ofC4；
(12) PWM in the step (7)A1、PWMA2、PWMA3、PWMA4PWM in step (9)B1、PWMB2、PWMB3、PWMB4PWM in step (11)C1、PWMC2、PWMC3、PWMC4And the three-phase current is sent to a corresponding switch device, so that active power factor correction is realized, the input current is sinusoidal, and under the condition of unbalanced network voltage, the balance control of the output direct current capacitor voltage is realized, so that the three-phase input current is balanced.
Referring to fig. 10, in the embodiment of the present invention, a three-phase input current waveform of a three-phase parallel rectifier formed by a five-level rectifier with a common high-voltage dc bus is provided, and under the condition of unbalanced three-phase grid voltage, the three-phase input current can be unbalanced by applying the control strategy of the present invention, and the current waveform has good quality and is approximately sinusoidal.
Referring to fig. 11, the two dc-side capacitor voltage waveforms U of the three-phase parallel rectifier formed by the five-level rectifier with the common high-voltage dc bus according to the embodiment of the present inventiono1、Uo2And a total output DC side voltage UdcThe voltage waveform on the direct current side has short time for reaching the steady state, and the direct current voltage has small fluctuation.
Referring to fig. 12, an input side five-level voltage waveform of a three-phase parallel rectifier formed by a five-level rectifier with a common high-voltage direct-current bus in the embodiment of the invention.
In other embodiments of the invention for use with a five-level rectifier having a common high-voltage dc bus, the three-phase star, delta and three-phase double star rectifiers described may be a combination of different circuits derived from the second module unit (B) in addition to the second module unit (B).
The five-level rectifier circuit with the common high-voltage direct-current bus can be simply applied to a high-power electronic rectification topological structure, the working efficiency of a system can be improved through a proper control strategy, the capacitor voltage on the direct-current side can be stably balanced, favorable conditions are provided for the later-stage electric energy conversion, and the five-level rectifier circuit has important application value in the application fields of medium-high voltage direct-current transmission, high-power electronic transformers, high-power medium-high voltage alternating-direct-alternating frequency converters and the like.
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the spirit and scope of the present invention, and various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design solutions of the present invention shall fall within the protection scope of the present invention, and the technical contents of the present invention as claimed are all described in the claims.

Claims (6)

1. A five-level rectifier with a common high-voltage direct-current bus, comprising a main power circuit comprising a high-frequency filter, a single-phase diode rectifier bridge, a boost inductance L and a first modular unit (a), characterized in that: the first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2With a cathode of said parallel connectionOutput DC capacitor C3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The first terminal (a) of the single-phase diode rectifier bridge is connected with one end of the boost inductor L, the other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, and the alternating current input end of the single-phase diode rectifier bridge is connected into an alternating current power grid in series through the high-frequency filter.
2. A three-phase parallel rectifier comprising a five-level rectifier with a common high voltage dc bus according to claim 1, comprising a three-phase main power circuit, wherein: the three-phase main power electricityThe circuit comprises three high-frequency filters and three second modular units (B) comprising a single-phase diode rectifier bridge, a boost inductor L and a first modular unit (A) comprising four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4With said output direct current connected in parallelContainer C4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with a rectification output positive end of the single-phase diode rectifier bridge, a direct current output positive end (g) of each phase of the second module unit (B) is connected, a direct current output negative end (h) of each phase of the second module unit (B) is connected, 2 residual alternating current input ends of the second module unit (B) of each phase are connected, the first alternating current input ends of the three phases of the second module unit (B) form a group of connection ends, the second alternating current input ends of the three phases of the second module unit (B) form another group of connection ends, one group of connection ends are connected to a common neutral point, the other group of connection ends are respectively connected with the three high-frequency filters in series and connected into a three-phase power grid to form a three-phase parallel connection.
3. The three-phase star rectifier formed by the five-level rectifier with the common high-voltage direct-current bus of claim 1 comprises a three-phase main power circuit, and is characterized in that: the three-phase main power circuit comprises three high-frequency filters and three second module units (B), wherein each second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit (A), and each first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the cathode and the output connected in parallelDC output capacitor C3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of the second module unit (B) of each phase are arranged, the first alternating current input ends of the three-phase second module unit (B) form a group of wiring ends, the second alternating current input ends of the three-phase second module unit (B) form another group of wiring ends, one group of wiring ends are connected to a common neutral point, the other group of wiring ends are respectively connected with the three high-frequency filters in series and connected into a three-phase power grid to form a three-phase power gridAnd (4) star connection.
4. A three-phase angle rectifier comprising a five-level rectifier with a common high voltage dc bus as claimed in claim 1, including a three-phase main power circuit, wherein: the three-phase main power circuit comprises three high-frequency filters and three second module units (B), wherein each second module unit (B) comprises a single-phase diode rectifier bridge, a boost inductor L and a first module unit (A), and each first module unit (A) comprises four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And the flying spanCapacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, 2 residual alternating current input ends of the second module unit (B) of each phase are arranged, the first alternating current input ends of the three phases of the second module unit (B) form a group of wiring ends, the second alternating current input ends of the three phases of the second module unit (B) form another group of wiring ends, one group of wiring ends are connected to the input end of a three-phase power grid through three high-frequency filters respectively, and the other group of wiring ends are sequentially connected to the input end of the next phase in the three-phase power grid to form an angular connection.
5. A three-phase double star rectifier formed by a five-level rectifier with a common high-voltage direct-current bus according to claim 1, comprising a three-phase main power circuit, wherein: the three-phase main power circuit comprises three high-frequency filters, six bridge arm inductors, a direct current capacitor and six second module units (B), wherein the six second module units (B) form two groups of butted star-shaped connections, in each group of star-shaped connections, the second module units (B) comprise single-phase diode rectifier bridges, boost inductors L and first module units (A), and the first module units (A) comprise four switching devices S1、S2、S3、S4Four fast recovery diodes D1、D2、D3、D4Two flying capacitors C1、C2Two output DC capacitors C3、C4And two load resistors R1、R2Said switching device S1And the fast recovery diode D1Is connected to the anode of the fast recovery diode D1And the fast recovery diode D2Is connected to the anode of the fast recovery diode D2And the output direct current capacitor C connected in parallel3And the load resistance R1Is connected to the first terminal (m), the output DC capacitor C is connected in parallel3And the load resistance R1With said output dc capacitor C connected in parallel to a second terminal (n) of4And the load resistance R2Is connected to the first terminal (m), said switching device S1And said switching device S2And said flying capacitor C1Is connected to the first terminal (e), said flying capacitor C1And said fast recovery diode D2Is connected to the anode of the switching device S2And said switching device S3And the output DC capacitor C connected in parallel4And the load resistance R2Is connected to the first terminal (m), said switching device S3And said switching device S4And said flying capacitor C2Is connected to the first terminal (e), said flying capacitor C2And said fast recovery diode D3And the fast recovery diode D4Is connected to the cathode of the fast recovery diode D4And the output direct current capacitor C connected in parallel4And the load resistance R2Is connected to the second terminal (n), said switching device S4And said fast recovery diode D3Is connected to the negative terminal of the rectified output of the single-phase diode rectifier bridge, and the switching device S1The first terminal (a) of the boost inductor L is connected with one end of the boost inductor L, the other end of the boost inductor L is connected with the positive end of the rectification output of the single-phase diode rectifier bridge, and each phase of the second module unit (B) has 2 residual alternating current input ends, namely a three-phase stationThe first alternating current input end of the second module unit (B) forms a group of wiring terminals, the second alternating current input end of the three-phase second module unit (B) forms another group of wiring terminals, one group of wiring terminals is connected to a common neutral point, the other group of wiring terminals are respectively connected with one end of each of the three bridge arm inductors, the other ends of the two bridge arm inductors on each phase of bridge arm are respectively connected with the other ends of the three bridge arm inductors and are respectively connected to the three-phase power grid input end through one of the three high-frequency filters, and meanwhile, the common neutral point in the first group of star connection and the common neutral point in the second group of star connection are respectively connected with the two ends of the direct current capacitor to form double star connection.
6. A five-level rectifier with a common high-voltage direct-current bus and a control strategy are characterized in that the control strategy of the five-level rectifier with the common high-voltage direct-current bus comprises the following steps:
(1) sampling the output side direct current voltage of a five-level rectifier with a common high-voltage direct current bus to obtain two output side direct current voltage signals Uo1、Uo2；
(2) Calculating two output side direct current voltage signals U in the step (1) by using the following formulao1、Uo2Average value of Uo，
Figure FDA0002769363440000031
(3) Mixing U in step (2)oWith a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulatord；
(4) Two output side direct current voltage signals U in the step (1)o1、Uo2Respectively associated with a given signal U of DC voltageo *After comparison, the obtained signal is sent to a PI voltage regulator to obtain the amplitude I of the direct current signal output by the PI voltage regulator1、I2；
(5) The amplitude I of the direct current signal in the step (4) is measured1、I2Respectively corresponding to the amplitude I of the DC current signal in the step (3)dAdding the obtained DC current to obtain a given signal amplitude I1 *、I2 *Setting the DC current to a signal amplitude I1 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik1 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I1 *Multiplying to generate a given current comparison signal ig1 *Setting the DC current to a signal amplitude I2 *Multiplied by a triangular carrier signal W to produce a given current comparison signal ik2 *The triangular carrier signal W is phase-shifted by 180 DEG and the DC current gives a signal amplitude I2 *Multiplying to generate a given current comparison signal ig2 *；
(6) Sampling three-phase power grid voltage to obtain an input side alternating voltage signal UA，UB，UCCalculating U by using the following formulaAm、UAn，
Figure FDA0002769363440000032
Calculating the negative sequence component U of the AC voltage signal at the input side of the A phase by using the following formulaAf，
UAf＝UAm+UAn
Calculating the negative sequence component U to be injected in the phase A by using the following formulaAz，
Figure FDA0002769363440000033
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Average value of (d); sampling three-phase power grid current to obtain an input side alternating current signal IA，IB，ICCalculating a comparison signal i of the A feedback current by using the following formulaA，
iA＝|IA|+UAz；
(7) Comparing the current given in step (5) with a signal ik1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA1PWM signal PWM ofA1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA2PWM signal PWM ofA2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA3PWM signal PWM ofA3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to A in step (6)ASending the signal into a comparator for comparison to obtain an A-phase switching device SA4PWM signal PWM ofA4；
(8) Calculate U using the equationBm、UBn，
Figure FDA0002769363440000041
In the formula of UA，UB，UCCalculating the negative sequence component U of the B-phase input side AC voltage signal for the input side AC voltage signal in the step (6) by using the following formulaBf，
UBf＝UBm+UBn
Calculating the negative sequence component U to be injected in the B phase by using the following formulaBz，
Figure FDA0002769363440000042
In the formula IdFor the output in step (3)Amplitude of the DC current signal, UoFor the output side DC voltage signal U in the step (2)o1、Uo2Using the following formula to calculate a comparison signal i of B feedback currentB，
iB＝|IB|+UBz
In the formula IBThe input side alternating current signal in the step (6);
(9) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of current opposite to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB1PWM signal PWM ofB1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB2PWM signal PWM ofB2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB3PWM signal PWM ofB3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to B in step (8)BSending the signals into a comparator for comparison to obtain a B-phase switching device SB4PWM signal PWM ofB4；
(10) Calculate U using the equationCm、UCn，
Figure FDA0002769363440000043
In the formula of UA，UB，UCCalculating the negative sequence component U of the C-phase input side AC voltage signal for the input side AC voltage signal in the step (6) by using the following formulaCf，
UCf＝UCm+UCn
Calculating the negative sequence component U to be injected in the C phase by using the following formulaCz，
Figure FDA0002769363440000044
In the formula IdFor the output of the DC current signal amplitude, U, in step (3)oFor the output side DC voltage signal U in the step (2)o1、Uo2Is calculated using the following formulaC，
iC＝|IC|+UCz
In the formula ICThe input side alternating current signal in the step (6);
(11) comparing the current given in step (5) with a signal ik1 *Feeding a comparison signal i of a current opposite to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC1PWM signal PWM ofC1Comparing the current given in step (5) with a signal ig1 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC2PWM signal PWM ofC2Comparing the current given in step (5) with a signal ik2 *Feeding a current comparison signal i in reverse to C in step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC3PWM signal PWM ofC3Comparing the current given in step (5) with a signal ig2 *Feeding a current comparison signal i in reverse to C of step (10)CSending the voltage into a comparator for comparison to obtain a C-phase switching device SC4PWM signal PWM ofC4；
(12) PWM in the step (7)A1、PWMA2、PWMA3、PWMA4PWM in step (9)B1、PWMB2、PWMB3、PWMB4PWM in step (11)C1、PWMC2、PWMC3、PWMC4The three-phase current is sent to a corresponding switch device to realize active power factor correction, so that the input current is sinusoidal, and under the condition of unbalanced network voltage, the balance control of the output direct current capacitor voltage is also realized, so that the three-phase current is realizedThe input current is balanced.
CN202011244123.1A 2020-11-10 2020-11-10 Five-level rectifier with public high-voltage direct-current bus and control strategy Pending CN112271940A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011244123.1A CN112271940A (en) 2020-11-10 2020-11-10 Five-level rectifier with public high-voltage direct-current bus and control strategy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011244123.1A CN112271940A (en) 2020-11-10 2020-11-10 Five-level rectifier with public high-voltage direct-current bus and control strategy

Publications (1)

Publication Number Publication Date
CN112271940A true CN112271940A (en) 2021-01-26

Family

ID=74340927

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011244123.1A Pending CN112271940A (en) 2020-11-10 2020-11-10 Five-level rectifier with public high-voltage direct-current bus and control strategy

Country Status (1)

Country Link
CN (1) CN112271940A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112838769A (en) * 2021-03-08 2021-05-25 中国矿业大学(北京) Transformer-isolation-free star-connection medium-high voltage variable frequency speed regulation system and control method
CN112994450A (en) * 2021-02-26 2021-06-18 华中科技大学 Capacitance voltage balance control method and system of five-level Buck/Boost converter
CN114499244A (en) * 2022-02-07 2022-05-13 中国矿业大学(北京) Medium-high voltage five-level rectifier and direct-current capacitor voltage balance control strategy

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112994450A (en) * 2021-02-26 2021-06-18 华中科技大学 Capacitance voltage balance control method and system of five-level Buck/Boost converter
CN112838769A (en) * 2021-03-08 2021-05-25 中国矿业大学(北京) Transformer-isolation-free star-connection medium-high voltage variable frequency speed regulation system and control method
CN114499244A (en) * 2022-02-07 2022-05-13 中国矿业大学(北京) Medium-high voltage five-level rectifier and direct-current capacitor voltage balance control strategy

Similar Documents

Publication Publication Date Title
CN112271940A (en) Five-level rectifier with public high-voltage direct-current bus and control strategy
CN103973121B (en) single-phase power electronic transformer
CN110611435B (en) Topological structure of cascade flexible alternating current chain converter
CN113676067A (en) Multi-phase AC/DC converter
CN109980968B (en) Modular multilevel converter, control system and application thereof
CN115250074B (en) Electrolytic hydrogen production rectifier with harmonic wave and ripple wave compensation function and control method
CN111953223A (en) Neutral point voltage balancing method for three-phase four-wire system three-level converter
CN114498718B (en) Flexible traction substation and control method thereof
CN103840684A (en) High-power compensation type cascade diode H-bridge unit power factor rectifier
Iman-Eini et al. Design of power electronic transformer based on cascaded H-bridge multilevel converter
Li et al. Operation, analysis and experiments of DC transformers based on modular multilevel converters for HVDC applications
CN111786579A (en) Cascaded multi-level rectifier with common high-voltage direct-current bus and control strategy
CN108306324B (en) Modularized centralized energy storage system
CN112838769A (en) Transformer-isolation-free star-connection medium-high voltage variable frequency speed regulation system and control method
CN112688576B (en) Five-level rectifier with public high-voltage direct-current bus and control strategy
CN113726136B (en) conversion device
CN113364306A (en) Two-phase-single-phase intersection direct-alternating cascade converter system
CN105024578A (en) Three-phase modular multilevel converter parallel system and control method thereof
CN111934558A (en) Implementation scheme of novel medium-high voltage variable frequency speed control system without transformer isolation
CN114977859B (en) Three-phase N-module cascading type unidirectional energy flow multi-level frequency converter and control method
CN215300518U (en) Five-level rectifier and three-phase rectifier with public high-voltage direct-current bus
CN110048623B (en) Line voltage cascade three-phase diode high-power factor converter and control strategy thereof
CN212850283U (en) Novel medium-high voltage variable frequency speed control system without transformer isolation
CN114499244B (en) Medium-high voltage five-level rectifier and direct-current capacitor voltage balance control strategy
CN212850304U (en) Cascaded multi-level rectifier with common high-voltage direct-current bus

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