CN203423490U - Z-source parallel active electric power filter - Google Patents
Z-source parallel active electric power filter Download PDFInfo
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- CN203423490U CN203423490U CN201320557575.4U CN201320557575U CN203423490U CN 203423490 U CN203423490 U CN 203423490U CN 201320557575 U CN201320557575 U CN 201320557575U CN 203423490 U CN203423490 U CN 203423490U
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- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/20—Active power filtering [APF]
Abstract
The utility model discloses a Z-source parallel active electric power filter, comprising an electrical network, a non-linear load, an output inductor, a Z-source inverter and a control circuit. The Z-source inverter comprises a DC source, a bidirectional switch S, a Z-source network and an inverter. The DC source is connected with the inverter through the Z-source network; and a bidirectional switch is connected between the positive terminal of the DC source and the Z-source network. The control system comprises a controller, a sensor unit and a power supply unit; the sensor unit comprises a voltage sensor for detecting the voltage of the electrical network, a current sensor for detecting a non-linear load current, a current sensor for detecting the compensation instruction current of the inverter and a voltage sensor for detecting the voltage of the DC source; the controller acquires the signals of the above sensors; and the bidirectional switch and the inverter are controlled by the controller through the acquired voltage and current values. According to the utility model, the dead zone time in switch signals is canceled, control complexity is reduced, and the output current waveform is not affected by DC voltage.
Description
Technical field
The utility model relates to a kind of Active Power Filter-APF, particularly a kind of Z source Shunt.
Background technology
As shown in Figure 1, existing Shunt is the main circuit adopting based on VSI inverter, between VSI inverter and electrical network, by output filter circuit, is connected with impedance inductance, and DC side consists of capacitor group.
As shown in Figure 2, the detection that the control circuit of existing parallel active filter can be real-time, harmonic current, reactive current, three-phase imbalance and the negative-sequence current in computational load electric current, and according to compensation model, determine the command value i that exports offset current
c *.DC bus capacitor device group has been mainly voltage supporting role in VSI inverter, its voltage V
ctherefore must remain relatively stable, at control circuit during in definite offset current instruction, for control capacitor group voltage V
cstable and add active current i
p *.Total output order electric current and current actual offset current i
cbetween difference DELTA i
c.The control circuit of the active electrical filter of this parallel connection is again according to above-mentioned difference DELTA i
c, line voltage U
g, impedance inductance value L determines the output voltage instruction U of VSI inverter
1 *, make curent change increment and Δ i in a switch periods T
cidentical, meet following formula:
This just causes existing scheme to have following some deficiency:
(1) the VSI inverter that adopts capacitor group to support as DC voltage, the conducting simultaneously of the switching device of its upper and lower bridge arm, otherwise can cause the short circuit of capacitor the two poles of the earth, burn out switching device and capacitor.Straight-through in order to prevent upper and lower bridge arm, control system, when determining the on off state of switching device, must add Dead Time, and this will inevitably cause output waveform to depart from control target, worsens compensation effect; Even if add dead band, control system still must add detection, the defencive function to straight-through fault, has increased control system complexity.
(2) the compensation harmonic electric current of the active electrical filter output of existing parallel connection can cause active power fluctuation, the leakage current of capacitor group, grading resistor also can cause certain active power loss, so DC bus capacitor device voltage control is complicated, must in compensating instruction electric current, add active current, can guarantee the stable of DC voltage, causing DC voltage control and output offset current to be controlled can not decoupling zero; Active current joins and in compensating instruction electric current, has also worsened compensation effect.In order to reduce voltage control difficulty, DC bus capacitor device is often taked the way of capacity increasing, but has improved cost.
(3) up to standard in order to guarantee the current change quantity in control cycle, the output voltage U of VSI inverter
1amplitude, phase place all need highly controlled, this voltage U if desired
1than line voltage U
gmuch higher.Control circuit adopts any output control algolithm, and the utilance of direct voltage, all lower than 1, be that is to say to the DC voltage of VSI inverter must compare U
gpeak value is high a lot
and this voltage will keep stable can guarantee compensation effect.The voltage levvl that direct current capacitor group is constant causes active electrical filter application flexibility in parallel to reduce.
Utility model content
The purpose of this utility model is to provide a kind of reliable Z source Shunt and control method thereof.
This Z source Shunt that the utility model provides, comprises electrical network, nonlinear load, output inductor, Z-source inverter and control circuit; Z-source inverter comprises DC source, bidirectional switch, Z source network and inverter, and DC source is connected with inverter by Z source network, between the positive terminal of described DC source and Z source network, is connected to a bidirectional switch; After the output series connection output inductor of described inverter, be connected between electrical network and nonlinear load; Described control system comprises controller, sensor unit and power subsystem, sensor unit comprise voltage sensor for real-time detection of grid voltage, for detect in real time nonlinear load electric current current sensor, for detect in real time inverter compensating instruction electric current current sensor and for detecting in real time the voltage sensor of DC source voltage, controller gathers the measuring-signal of the sensor, for bidirectional switch and inverter being controlled by the magnitude of voltage, the current value that gather.
Described DC source adopts energy storage capacitor group, for DC side, supplements leaky condenser and the fluctuation of supplementary harmonic wave active power; Described DC source or adopt the DC power supply of spread of voltage, for realizing the grid-connected of the two-way flow of electric energy and active power.Described bidirectional switch adopts IGBT device.Described Z source network is a two-port network, is used to described inverter that Equivalent DC voltage support is provided; This Z source network comprises inductance L
1, inductance L
2and intersection is connected to inductance L
1and inductance L
2between capacitor C
1and capacitor C
2.Described inverter adopts the three-phase inverter bridge circuit being comprised of some semiconductor switch devices.Described semiconductor switch device adopts IGBT device, and it is without short-circuit protection, and its operating state is without adding dead band.
Compare with prior art scheme, the utlity model has following advantage:
(1) inverter switching states of the present utility model is except 6 nonzero voltage space vectors of routine, 2 Zero voltage vectors, many 1 zero vectors that upper and lower bridge arm is straight-through, therefore the switch of inverter control in without adding dead band, the pass-through state in the short time can not burn out switching device, DC source and Z source network yet.
(2) the utility model adopts DC source and Z source network etc. to form after DC side, the DC voltage control of inverter is mainly completed by straight-through zero vector, control and to realize decoupling zero with output offset current, reduced control complexity, output current wave is not subject to the impact of direct voltage substantially.
(3) the voltage support function of the utility model inverter direct-flow side and energy-storage function are independent separately, and voltage support function is mainly born by Z source network, and energy-storage function is mainly born by DC bus capacitor device.The voltage of energy storage capacitor group can change and not affect compensation effect.In addition, energy storage capacitor group can replace with photovoltaic cell, storage battery or fuel cell, is convenient to combine use with generation of electricity by new energy, distributed energy storage system etc., and the flexibility of systemic-function improves greatly.
(4) the utility model is controlled DC side equivalent voltage by straight-through accounting, has cancelled the Dead Time in switching signal, and simplifies device protection.
Accompanying drawing explanation
Fig. 1 is the main circuit diagram of prior art.
Fig. 2 is the control flow chart of prior art.
Fig. 3 is main circuit diagram of the present utility model.
Fig. 4 is the equivalent circuit diagram of inverter front end under the utility model Z-source inverter pass-through state.
Fig. 5 is the equivalent circuit diagram of inverter front end under the non-pass-through state of the utility model Z-source inverter.
Fig. 6 is control flow chart of the present utility model.
Embodiment
The utility model comprises main circuit and the corresponding control circuit that Z-source inverter forms.
One, the main circuit that Z-source inverter forms.
The main circuit that Z-source inverter forms comprises electrical network, nonlinear load, output inductor, Z-source inverter and control circuit; Z-source inverter comprises DC source, bidirectional switch, Z source network and inverter, and DC source is connected with inverter by Z source network, between the positive terminal of DC source and Z source network, is connected to a bidirectional switch; Control system comprises controller, sensor unit and power subsystem, sensor unit comprises for the voltage sensor of real-time detection of grid voltage, for the current sensor of real-time detection nonlinear load electric current with for detecting in real time the voltage sensor of DC source voltage, controller gathers the measuring-signal of the sensor, for bidirectional switch and inverter being controlled by the magnitude of voltage, the current value that gather.
DC source of the present utility model preferably adopts energy storage capacitor group, for DC side, supplements leaky condenser and the fluctuation of supplementary harmonic wave active power.This DC source can also adopt other DC power supply to replace, such as photovoltaic cell, fuel cell, magneto alternator, chargeable storage etc.The voltage of these DC power supply all changes within the specific limits, for realizing the grid-connected of the two-way flow of electric energy and active power.
Bidirectional switch of the present utility model can adopt the controlled IGBT device of high speed.
Z source network of the present utility model is a two-port network being comprised of some inductance and some electric capacity, is used to inverter that Equivalent DC voltage support is provided.
Inverter adopts the three-phase inverter bridge circuit being comprised of some semiconductor switch devices.Semiconductor switch device is without short-circuit protection, and its operating state is without adding dead band.Semiconductor switch device of the present utility model preferably adopts IGBT device.
As shown in Figure 3, the main circuit that Z-source inverter of the present utility model forms comprises electrical network, nonlinear load, output inductor L and Z-source inverter.Z-source inverter comprises capacitor group C, bidirectional switch S, Z source network and inverter.Z source network comprises inductance L
1, inductance L
2, capacitor C
1with capacitor C
2.
The positive pole of capacitor group C is by bidirectional switch S series inductance L
1be connected with the electrode input end of inverter; The negative pole of capacitor group C passes through inductance L
2be connected with the negative input of inverter; Polar capacitor C
1positive terminal and inductance L
1the side that is connected with bidirectional switch S connect, its negative pole end and inductance L
2the side that is connected with inverter connect; Polar capacitor C
2positive terminal and inductance L
1the side that is connected with inverter connect, its negative pole end and inductance L
2the side that is connected with capacitor group C connect; The output of inverter is connected with electrical network by output inductor L, and the output of this inverter is also connected with nonlinear load by output inductor L.
The voltage U of energy storage capacitor group C
dCcan keep lower value, and can change, capacitors count requires less, and can play the effect of energy storage.Because its change in voltage scope is larger, also can adopt the instead of capacitor groups such as fuel cell, photovoltaic cell as energy-storage units, make Shunt have the grid-connected function of active power concurrently.
Capacitor C in Z source network
1with capacitor C
2all play the effect of voltage support, with the inductance L in this network
1and inductance L
2jointly for inverter provides direct voltage.
Two, control circuit.
Control circuit of the present utility model comprises controller, sensor unit and power subsystem, sensor unit comprise voltage sensor for real-time detection of grid voltage, for detect in real time nonlinear load electric current current sensor, for detect in real time inverter compensating instruction electric current current sensor and for detecting in real time the voltage sensor of DC source voltage, controller gathers the measuring-signal of the sensor, then by the magnitude of voltage, the current value that gather, bidirectional switch and inverter is controlled.
Because circuit structure of the present utility model changes, control method of the present utility model is adjusted change thereupon.
(1) mode of operation of Z-source inverter.
Except conventional VSI inverter 8 in operating state, Z-source inverter also has the straight-through operating state of upper and lower bridge arm.
Due to the symmetry of circuit, can suppose U under stable state
c1=U
c2=u
c, U
l1=U
l2=u
l.
As shown in Figure 4, under the mode of operation at Z-source inverter in pass-through state, bidirectional switch S disconnects, and has U
c=-U
l.As shown in Figure 5, under the mode of operation at Z-source inverter in non-pass-through state, bidirectional switch S conducting, has U
c=U
l+ U
dC.If setting the straight-through time is T
0, whole switch periods is T, the non-straight-through time is T
1=T-T
0, its straight accounting D=T
0/ T, Support Capacitor voltage u
cwith energy storage capacitor group voltage U
dCrelation can be write as:
Hence one can see that, and under above-mentioned non-pass-through state, the direct voltage of inverter equivalence is:
(2) control method of the present utility model.
After adopting Z-source inverter, Current Detection Algorithm of the present utility model does not change, but its instruction current calculates and main circuit switch pattern control algolithm has had great variation, and flow chart as shown in Figure 6.
Control method of the present utility model comprises the steps:
Step 1, controller obtains line voltage U
g, nonlinear load current i
l, inverter compensating instruction current i
cwith DC source voltage U
dC.
Step 2, controller, according to the mode of operation of Z-source inverter, calculates the pass-through state time accounting D of inverter in control cycle; By accounting D, regulate the voltage of energy storage capacitor group in prescribed limit again, and can guarantee the stable of Z-source inverter DC side equivalent voltage.
Step 3, controller is to line voltage U
gcurrent i with nonlinear load
ldo dot product and obtain instantaneous active power P (t), by said two devices being done to cross product, obtain instantaneous reactive power Q (t); Again by low pass filter by time variation amount filtering, obtain active-power P and the reactive power Q of fundamental positive sequence; By the active-power P of fundamental positive sequence and reactive power Q respectively divided by U
g 2and the fundamental positive sequence current i comprising in acquisition load current after being added
f; Use load current i
ldeduct fundamental positive sequence current i
fbe compensated instruction current i
c *; By current actual compensating instruction current i
cdeduct compensating instruction current i
c *obtain line voltage U
gwith the instruction current variation delta i within control cycle T
c; Again by instruction current variation delta i
caccording to following formula, calculate inverter output order voltage U
1 *,
In formula, the inductance value that L is output inductor; Then according to inverter output order voltage U
1 *use SVPWM algorithm to calculate output time (the non-pass-through state time) T of non-zero vector
1; Finally according to output time T
1, and in conjunction with the pass-through state time accounting D of above-mentioned inverter, use SVPWM algorithm to calculate the switching mode S of IGBT device
a, B, C, now should keep energy storage capacitor group voltage U
dCexcursion in presetting scope.
Step 3, controller is according to the switching mode S of the IGBT of institute device
a, B, C, each IGBT device of inverter is controlled in real time.
Fundamental positive sequence composition in instantaneous power, at instantaneous active power P (t) and instantaneous reactive power Q (t), show as DC component, and the compositions such as fundamental wave zero sequence, negative phase-sequence, harmonic current variation amount while all showing as in instantaneous active power P (t) and instantaneous reactive power Q (t).
When energy storage capacitor group voltage U
dCduring lower than minimum threshold, in output compensating instruction current i
c *in add fixing fundamental active current component, now inverter can absorption portion active power and energy storage capacitor group is charged, and charges to energy storage capacitor group voltage U
dCwhile reaching wealthy family limit value, stop absorbing active power.The electric energy that energy storage capacitor group stores is just used for the leakage current of compensation condenser, and harmonic wave active power is divided into 0 in primitive period inner product, therefore the operating state that absorbs active power only accounts for very little part in Z-source inverter, and active current amplitude is fixed, very little for the impact of compensation effect.
The utility model adopts after Z-source inverter can direct grid-connected, to electrical network, carries active power and no longer needs DC-DC voltage to keep link, greatly reduces system complexity and circuit cost.The utility model can also, by the computational methods of output order electric current in control system, be realized several functions easily.
Claims (6)
1. a Z source Shunt, comprises electrical network, nonlinear load, output inductor, it is characterized in that, this filter also comprises Z-source inverter and control circuit; Z-source inverter comprises DC source, bidirectional switch, Z source network and inverter, and DC source is connected with inverter by Z source network, between the positive terminal of described DC source and Z source network, is connected to a bidirectional switch; After the output series connection output inductor of described inverter, be connected between electrical network and nonlinear load; Described control system comprises controller, sensor unit and power subsystem, sensor unit comprise voltage sensor for real-time detection of grid voltage, for detect in real time nonlinear load electric current current sensor, for detect in real time inverter compensating instruction electric current current sensor and for detecting in real time the voltage sensor of DC source voltage, controller gathers the measuring-signal of the sensor, for bidirectional switch and inverter being controlled by the magnitude of voltage, the current value that gather.
2. Z according to claim 1 source Shunt, is characterized in that, described DC source adopts energy storage capacitor group, for DC side, supplements leaky condenser and the fluctuation of supplementary harmonic wave active power; Described DC source or adopt the DC power supply of spread of voltage, for realizing the grid-connected of the two-way flow of electric energy and active power.
3. Z according to claim 1 source Shunt, is characterized in that, described bidirectional switch adopts IGBT device.
4. Z according to claim 1 source Shunt, is characterized in that, described Z source network is a two-port network, is used to described inverter that Equivalent DC voltage support is provided; This Z source network comprises inductance L
1, inductance L
2and intersection is connected to inductance L
1and inductance L
2between capacitor C
1and capacitor C
2.
5. Z according to claim 1 source Shunt, is characterized in that, described inverter adopts the three-phase inverter bridge circuit being comprised of some semiconductor switch devices.
6. Z according to claim 5 source Shunt, is characterized in that, described semiconductor switch device adopts IGBT device, and it is without short-circuit protection, and its operating state is without adding dead band.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320557575.4U CN203423490U (en) | 2013-09-10 | 2013-09-10 | Z-source parallel active electric power filter |
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|---|---|---|---|
| CN201320557575.4U CN203423490U (en) | 2013-09-10 | 2013-09-10 | Z-source parallel active electric power filter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414194A (en) * | 2013-09-10 | 2013-11-27 | 威胜集团有限公司 | Z-source inverter shunt active power filter and control method thereof |
| CN110018384A (en) * | 2018-01-09 | 2019-07-16 | Abb瑞士股份有限公司 | Method for detecting the ground fault condition in power conversion unit |
| CN111526625A (en) * | 2020-06-08 | 2020-08-11 | 宁波奥克斯电气股份有限公司 | Intelligent dimming device and method and air conditioner |
| CN112415255A (en) * | 2020-11-14 | 2021-02-26 | 陕西航空电气有限责任公司 | Improved active current sampling circuit |
-
2013
- 2013-09-10 CN CN201320557575.4U patent/CN203423490U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414194A (en) * | 2013-09-10 | 2013-11-27 | 威胜集团有限公司 | Z-source inverter shunt active power filter and control method thereof |
| CN103414194B (en) * | 2013-09-10 | 2015-06-17 | 威胜集团有限公司 | Z-source inverter shunt active power filter and control method thereof |
| CN110018384A (en) * | 2018-01-09 | 2019-07-16 | Abb瑞士股份有限公司 | Method for detecting the ground fault condition in power conversion unit |
| CN110018384B (en) * | 2018-01-09 | 2023-04-14 | Abb瑞士股份有限公司 | Method for detecting a ground fault condition in a power conversion device |
| CN111526625A (en) * | 2020-06-08 | 2020-08-11 | 宁波奥克斯电气股份有限公司 | Intelligent dimming device and method and air conditioner |
| CN112415255A (en) * | 2020-11-14 | 2021-02-26 | 陕西航空电气有限责任公司 | Improved active current sampling circuit |
| CN112415255B (en) * | 2020-11-14 | 2023-10-24 | 陕西航空电气有限责任公司 | Improved active current sampling circuit |
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| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140205 |