CN105846688A - Method for controlling five-phase six-wire matrix converter carrying unbalanced loads - Google Patents

Abstract

The invention discloses a method for controlling five-phase six-wire matrix converter carrying unbalanced loads. By applying an indirect conversion method, a five-phase six-wire matrix converter is equivalent to a virtual alternating-direct-alternating structure which comprises a virtual rectifier stage and a virtual inverter stage. On this basis, a traditional double space vector modulation strategy is applied to a 3*5 part, and a duty ratio of a corresponding vector combination is obtained; a PWM method is applied to modulating a central line bridge arm alone, a duty ration of the central line bridge arm is analyzed and derived, voltage of a load neutral point is controlled to be a corresponding zero sequence voltage, a switching sequence of the 3*5 part and the central line bridge arm is reasonably optimized, and switchover frequency is minimized in a modulation period. Test results show that the method disclosed in the invention can enable the five-phase six-wire matrix converter to have sinusoidal asymmetric five phase load voltage when the five-phase six-wire matrix converter carries balanced loads or unbalanced loads.

Description

Five phase six line matrix converter control method under unbalanced load

Technical field

The invention belongs to electronic power converter control field, be five phase six line matrix converters under a kind of unbalanced load Control method, the problem of output loading Voltage unbalance during for solving five phase matrix converter band unbalanced loads.

Background technology

Along with the fast development of converters, motor driven systems gradually breaks away from the constraint of the number of phases, and by heterogeneous, the number of phases is big Converter in 3 is powered polyphase machine drive system, provides new approach for realizing High-power AC drives, and polyphase matrix becomes The most therefore parallel operation has obtained studying widely.Compared with traditional three-phase drive system, polyphase machine drive system has many excellent Point, failure tolerance therein can improve the reliability of system, i.e. breaks down (phase when a certain phase of polyphase machine or a few phase When in unbalanced load) and cannot properly functioning time, system remains to normally carry out fall volume operation mutually with remaining, and without shutting down. On the other hand, in actual applications, matrix converter is frequently encountered the situation of laod unbalance.Will lead during laod unbalance Cause load voltage is asymmetric, and asymmetric load voltage is unfavorable for the properly functioning of load, even can damage load.

Topology and the research relative maturity of control strategy thereof to the matrix converter band unbalanced load that three-phase exports at present, three Phase four bridge legs matrix converter applies the modulation principle of three-dimensional space vector of voltage so that three-phase four-arm matrix converter has Good using value.But, present stage for the matrix converter band unbalanced load of heterogeneous output correlative study relatively Few.And three-dimensional voltage space vector modulation method application in the matrix converter band unbalanced load of heterogeneous output seems Complex.

Summary of the invention

It is an object of the invention to, propose a kind of scientific and reasonable, applicability is strong, five phase six line square under the unbalanced load that effect is good Battle array inverter control method.

Realize goal of the invention employed technical scheme comprise that, five phase six line matrix converter control methods under a kind of unbalanced load, Wherein, five phase six line matrix converters are made up of 18 two-way power switch, 15 in described 18 power switch Three-phase input power and five phase loads being connected, the other three power switch is connected at load neutral point by center line brachium pontis, its In arbitrarily input mutually by six of which power switch with export five phases and center line brachium pontis is connected, it is characterised in that: application change indirectly Changing method, five phase six line matrix converters are equivalent to virtual AC-DC-AC structure, described virtual AC-DC-AC structure includes virtual whole Stream level and virtual inverse cascade, on this basis, the Double Space Vector Modulation strategy to 3 × 5 certain applications therein, and obtain phase Answering the dutycycle of vectorial combination, center line brachium pontis individually uses PWM method to be modulated simultaneously, analyzes, derives center line bridge The dutycycle of arm, and the voltage controlling load neutral point is corresponding residual voltage, then reasonably optimizing 3 × 5 part and center line bridge The switching sequence of arm so that it is the switching times within a modulation period is minimum.

The function expression of described dutycycle is:

Virtual rectification stage duty cycle functions:

$\left\{\begin{array}{c}{d}_{\mathrm{\μ}}=T_{\mathrm{\μ}}/T_s=m_{c}sin(\mathrm{\π}/3-{\mathrm{\θ}}_c)\\ d_{\mathrm{\γ}}=T_{\mathrm{\γ}}/T_s=m_{c}sin\left({\mathrm{\θ}}_c\right)\\ d_{0c}=T_{0c}/T_s=1-d_{\mathrm{\μ}}-d_{\mathrm{\γ}}\end{array}\right.$

In formula, m_cFor current-modulation ratio；θ_cFor input current sector angle；T_sFor modulation period；T_μ、T_γ、T_0cAnd d_μ、d_γ、 d_0cIt is respectively time and the dutycycle of corresponding vector；

In virtual inverse cascade, the duty cycle functions of five phase brachium pontis is:

$\left\{\begin{array}{c}{d}_{\mathrm{\α}L}=T_{\mathrm{\α}L}/T_s=\frac{1}{sin(4\mathrm{\π}/5)}\frac{1}{\mathrm{\η}\·M+L}\frac{U_{om}}{u_{pn}}sin(\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)\\ d_{\mathrm{\α}M}=T_{\mathrm{\α}M}/T_s=\mathrm{\η}\·d_{\mathrm{\α}L}\\ d_{\mathrm{\β}L}=T_{\mathrm{\β}L}/T_s=\frac{1}{sin(4\mathrm{\π}/5)}\frac{1}{\mathrm{\η}\·M+L}\frac{U_{om}}{u_{pn}}sin\left({\mathrm{\θ}}_v\right)\\ d_{\mathrm{\β}M}=T_{\mathrm{\β}M}/T_s=\mathrm{\η}\·d_{\mathrm{\β}L}\\ d_{0v}=T_{0v}/T_s=1-(d_{\mathrm{\α}L}+d_{\mathrm{\α}M}+d_{\mathrm{\β}L}+d_{\mathrm{\β}M})\end{array}\right.$

In formula, U_omFor output phase voltage amplitude；θ_vFor angle, output voltage sector；u_pnThe DC voltage exported for virtual rectification stage； M=0.4；L=0.8cos (π/5)；T_αL、T_αM、T_βL、T_βMAnd d_αL、d_αM、d_βL、d_βMIt is respectively the action time of respective vectors And dutycycle；η is the relative ratios of the middle vector on same direction and big vector；In order to ensure to export five phase voltage waveforms for sine Ripple, η should be equal to 0.618；

The duty cycle functions of the vectorial combination of described 3 × 5 parts is:

$\left\{\begin{array}{c}{d}_{\mathrm{\μ}\mathrm{\α}M}=d_{\mathrm{\μ}}\·d_{\mathrm{\α}M};d_{\mathrm{\μ}\mathrm{\α}L}=d_{\mathrm{\μ}}\·d_{\mathrm{\α}L};d_{\mathrm{\μ}\mathrm{\β}M}=d_{\mathrm{\μ}}\·d_{\mathrm{\β}\mathrm{\α}M};d_{\mathrm{\μ}\mathrm{\β}L}=d_{\mathrm{\μ}}\·d_{\mathrm{\β}L}\\ d_{\mathrm{\γ}\mathrm{\α}M}=d_{\mathrm{\γ}}\·d_{\mathrm{\α}M};d_{\mathrm{\γ}\mathrm{\α}L}=d_{\mathrm{\γ}}\·d_{\mathrm{\α}L};d_{\mathrm{\γ}\mathrm{\β}M}=d_{\mathrm{\γ}}\·d_{\mathrm{\β}\mathrm{\α}M};d_{\mathrm{\γ}\mathrm{\β}L}=d_{\mathrm{\γ}}\·d_{\mathrm{\β}L}\\ d_0=1-(d_{\mathrm{\μ}\mathrm{\α}M}+d_{\mathrm{\μ}\mathrm{\α}L}+d_{\mathrm{\μ}\mathrm{\β}M}+d_{\mathrm{\μ}\mathrm{\β}L}+d_{\mathrm{\γ}\mathrm{\α}M}+d_{\mathrm{\γ}\mathrm{\α}L}+d_{\mathrm{\γ}\mathrm{\β}M}+d_{\mathrm{\γ}\mathrm{\β}L})\end{array}\right.$

Described zero sequence voltage component is

$u_{rZ}=\frac{1}{\sin (4\mathrm{\π}/5)}\frac{(1+\mathrm{\η})}{\mathrm{\η}\·M+L}\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+\sin \left({\mathrm{\θ}}_v\right)\]-u_{\max }$

Wherein, u_rZFor zero sequence voltage component, u_maxFor exporting the maximum of five phase voltages；

In described virtual inverse cascade, the duty cycle functions of center line brachium pontis is:

$d_N=\frac{u_{rZ}}{u_{pn}}+0.5$

It is further:

(1) on the equivalent AC-DC-AC architecture basics of five phase six line matrix converters, according to space vector modulation algorithm, really In a fixed switch periods, each vector duty cycle d of virtual rectification stage_μ、d_γ、d_0cEach arrow with five phase brachium pontis in virtual inverse cascade Amount dutycycle d_αL、d_αM、d_βL、d_βM、d_0v；Each vector duty cycle of two-stage is combined and obtains 3 × 5 each vectorial combinations of part Dutycycle d_μαL、d_μαM、d_μβL、d_μβM、d_γαL、d_γαM、d_γβL、d_γβMAnd d₀；

(2) center line brachium pontis uses PWM method, and its dutycycle is d_N, controlling load neutral point voltage is corresponding zero sequence electricity Pressure u_rZSo that it is under unbalanced load, obtain the load voltage of symmetry；

(3) 3 × 5 parts of five phase six line matrix converters and the on off state of center line brachium pontis are optimized combination, rationally Arrange the sequence of switches, it is ensured that the switching times in the modulation period is minimum.

Compared with prior art, the invention has the beneficial effects as follows:

Five phase six line matrix converter control method under a kind of unbalanced load of the present invention, it is possible to make it uneven at five phase loads Still ensure that output loading voltage symmetry during weighing apparatus, in the case of phase shortage, also can ensure the properly functioning of other phase, to the center line introduced Brachium pontis uses PWM method individually to control, and remainder uses space vector modulation algorithm, and modulator approach is the most square Just, it is to avoid using the complexity of three-dimensional voltage space vector modulation method, have methodological science reasonable, applicability is strong, effect The advantage such as good.

Accompanying drawing explanation

Fig. 1 is the topology diagram of five phase six line matrix converters；

Fig. 2 is the equivalent AC-DC-AC model structure figure of five phase six line matrix converters；

Fig. 3 is the input current space vector distribution schematic diagram of virtual rectification stage；

Fig. 4 is that reference input current phasor synthesizes schematic diagram；

Fig. 5 is the space vector of voltage distribution schematic diagram at first harmonic spatial of virtual inverse cascade；

Fig. 6 is reference output voltage Vector modulation schematic diagram；

Fig. 7 is the complete topology structure chart of inverse cascade band unbalanced load；

Fig. 8 is the sequence of switches schematic diagram within a modulation period；

Fig. 9 is the simulation waveform figure under balanced load；

Figure 10 is the simulation waveform figure under unbalanced load；

Figure 11 is under unbalanced load, Output simulation oscillogram when B phase breaks.

Detailed description of the invention

With specific embodiment, technical solution of the present invention is described in further detail below in conjunction with the accompanying drawings.

Five phase six line matrix converter control method under a kind of unbalanced load of the present invention so that it is in balanced load and imbalance The symmetry of phase output voltage is all can guarantee that in the case of load.The topological structure of five phase six line matrix converters as it is shown in figure 1, The center line brachium pontis newly increased is connected at the neutral point of five phase loads.Its equivalence AC-DC-AC model is at five phase matrix converters Adding the equivalence of center line brachium pontis on the basis of equivalent model, the model after equivalence is by virtual rectification stage and five virtual phases six The cascade of line inverse cascade forms, as shown in Figure 2.

The input current space vector of virtual rectification stage is distributed as it is shown on figure 3, it includes 3 null vectors of 6 effective current vectors Amount.As reference input current phasor I_refIt is positioned at a certain sector, can be by the two of this sector adjacent effective vector I_μ, I_γAnd Zero vector I₀Synthesize, as shown in Figure 4.I_refIt is represented by

I_ref=d_μI_μ+d_γI_γ+d_0cI₀ (1)

Convolution (1), can be obtained by sine

$\left\{\begin{array}{c}{d}_{\mathrm{\μ}}=T_{\mathrm{\μ}}/T_s=m_{c}sin(\mathrm{\π}/3-{\mathrm{\θ}}_c)\\ d_{\mathrm{\γ}}=T_{\mathrm{\γ}}/T_s=m_{c}sin\left({\mathrm{\θ}}_c\right)\\ d_{0c}=T_{0c}/T_s=1-d_{\mathrm{\μ}}-d_{\mathrm{\γ}}\end{array}\right.---\left(2\right)$

In formula, m_cFor current-modulation ratio；θ_cFor input current sector angle；T_sFor modulation period；T_μ、T_γ、T_0cAnd d_μ、d_γ、 d_0cIt is respectively time and the dutycycle of corresponding vector.

The space vector of voltage of virtual inverse cascade first harmonic spatial distribution as shown in Figure 5.It includes 30 effective vectors (ten Big vector, ten small vectors of ten middle vectors) and 2 Zero voltage vectors.Each voltage sector all has six effective vectors adjacent, In order to obtain the output reference voltage U of maximum_ref, only select adjacent two big vector U_αL, U_βLWith two middle vector U_αM, U_βMAnd zero vector U₀Come synthesized reference output voltage vector, as shown in Figure 6, the U in figure_αAnd U_βFor

$\left\{\begin{array}{c}{U}_{\mathrm{\α}}=d_{\mathrm{\α}L}{U}_{\mathrm{\α}L}+d_{\mathrm{\α}M}{U}_{\mathrm{\α}M}\\ U_{\mathrm{\β}}=d_{\mathrm{\β}L}{U}_{\mathrm{\β}L}+d_{\mathrm{\β}M}{U}_{\mathrm{\β}M}\end{array}\right.---\left(3\right)$

Convolution (3), U_refIt is represented by

U_ref=d_αLU_αL+d_αMU_αM+d_βLU_βL+d_βMU_βM+d₀U₀ (4)

According to formula (3) and formula (4), sine can obtain

$\left\{\begin{array}{c}{d}_{\mathrm{\α}L}=T_{\mathrm{\α}L}/T_s=\frac{1}{sin(4\mathrm{\π}/5)}\frac{1}{\mathrm{\η}\·M+L}\frac{U_{om}}{u_{pn}}sin(\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)\\ d_{\mathrm{\α}M}=T_{\mathrm{\α}M}/T_s=\mathrm{\η}\·d_{\mathrm{\α}L}\\ d_{\mathrm{\β}L}=T_{\mathrm{\β}L}/T_s=\frac{1}{sin(4\mathrm{\π}/5)}\frac{1}{\mathrm{\η}\·M+L}\frac{U_{om}}{u_{pn}}sin\left({\mathrm{\θ}}_v\right)\\ d_{\mathrm{\β}M}=T_{\mathrm{\β}M}/T_s=\mathrm{\η}\·d_{\mathrm{\β}L}\\ d_{0v}=T_{0v}/T_s=1-(d_{\mathrm{\α}L}+d_{\mathrm{\α}M}+d_{\mathrm{\β}L}+d_{\mathrm{\β}M})\end{array}\right.---\left(5\right)$

In formula, U_omFor output phase voltage amplitude；θ_vFor angle, output voltage sector；M=0.4；L=0.8cos (π/5)；T_αL、T_αM、 T_βL、T_βMAnd d_αL、d_αM、d_βL、d_βMIt is respectively action time and the dutycycle of respective vectors.η is the middle arrow on same direction Amount and the relative ratios of big vector.In order to ensure that exporting five phase voltage waveforms is sine wave, η should be equal to 0.618.

The virtual rectification stage of five phase matrix converters and the duty of the vectorial combination of virtual inverse cascade can be obtained by formula (2) and formula (5) Ratio:

$\left\{\begin{array}{c}{d}_{\mathrm{\μ}\mathrm{\α}M}=d_{\mathrm{\μ}}\·d_{\mathrm{\α}M};d_{\mathrm{\μ}\mathrm{\α}L}=d_{\mathrm{\μ}}\·d_{\mathrm{\α}L};\\ d_{\mathrm{\μ}\mathrm{\β}M}=d_{\mathrm{\μ}}\·d_{\mathrm{\β}\mathrm{\α}M};d_{\mathrm{\μ}\mathrm{\β}L}=d_{\mathrm{\μ}}\·d_{\mathrm{\β}L};\\ d_{\mathrm{\γ}\mathrm{\α}M}=d_{\mathrm{\γ}}\·d_{\mathrm{\α}M};d_{\mathrm{\γ}\mathrm{\α}L}=d_{\mathrm{\γ}}\·d_{\mathrm{\α}L};\\ d_{\mathrm{\γ}\mathrm{\β}M}=d_{\mathrm{\γ}}\·d_{\mathrm{\β}\mathrm{\α}M};d_{\mathrm{\γ}\mathrm{\β}L}=d_{\mathrm{\γ}}\·d_{\mathrm{\β}L};\\ d_0=1-(d_{\mathrm{\μ}\mathrm{\α}M}+d_{\mathrm{\μ}\mathrm{\α}L}+d_{\mathrm{\μ}\mathrm{\β}M}+d_{\mathrm{\μ}\mathrm{\β}L}+d_{\mathrm{\γ}\mathrm{\α}M}+d_{\mathrm{\γ}\mathrm{\α}L}+d_{\mathrm{\γ}\mathrm{\β}M}+d_{\mathrm{\γ}\mathrm{\β}L})\end{array}\right.---\left(6\right)$

The task of virtual rectification stage is to be modulated three-phase input voltage, and output DC voltage powers to virtual inverse cascade, load On output voltage exported by virtual inverse cascade, so when input voltage is symmetrical, load for unbalanced load time, it is right only to need Virtual inverse cascade in Fig. 2 is analyzed.Virtual inverse cascade band in the equivalent topologies of five phase six line matrix converters is uneven The complete topology structure of resistance sense load is as shown in Figure 7.

The DC voltage u of virtual rectification stage output_pnFor steady state value.For the ease of analyzing, it is assumed that u_pnIt is divided into two parts, in Point is O, and current potential is zero.L_fAnd C_fFor output inductor and filter capacitor；u_AO、u_BO、u_CO、u_DO、u_EOFor output five The phase brachium pontis voltage to O point, u_NOFor the center line brachium pontis voltage to O point；u_AN、u_BN、u_CN、u_DN、u_ENIt is five phase loads Voltage；i_A、i_B、i_C、i_D、i_EIt is five phase load electric currents, i_NOutput electric current for center line brachium pontis.Output voltage can be obtained by figure Equation:

u_XO-u_NO=L_f·di_X/dt+u_XN, X=A, B, C, D, E (7)

Due to output inductor L_fValue the least, therefore L_f·di_X/ dt can ignore, then five phase output voltages by five phase brachium pontis to O point Voltage and load neutral point voltage determine, the nodal method of analysis can calculate neutral point voltage u_NO:

$u_{NO}=\frac{u_{AO}{Y}_A^{\′}+u_{BO}{Y}_B^{\′}+u_{CO}{Y}_C^{\′}+u_{CO}{Y}_D^{\′}+u_{CO}{Y}_E^{\′}}{Y_A^{\′}+Y_B^{\′}+Y_C^{\′}+Y_D^{\′}+Y_E^{\′}}---\left(8\right)$

In formula,

$Y_X^{\′}=\frac{1}{Z_X^{\′}}=\frac{1}{Z_X//Z_{C_f}+Z_{L_f}},X=A,B,C,D,E---\left(9\right)$

Wherein, Y '_XFor output resultant admittance, Z '_XFor output total impedance, Z_X、WithIt is respectively load impedance, filter capacitor impedance With filter inductance impedance.

For five phase matrix converters, owing to five phase loads are asymmetric, from formula (8), the current potential u of load neutral point_NO It is no longer 0, there occurs drift.Convolution (7) knows that the voltage in load is no longer five symmetrical sine waves, so five phase matrixs Converter can not band unbalanced load.When using five phase six line matrix converters, the current potential of load neutral point just can be by center line The output voltage u of brachium pontis_NOControl, as long as center line brachium pontis uses suitable control method, it is possible to obtain five phase sines right The output voltage claimed.

Assume that exporting five phase reference voltages is

$\left[\begin{array}{c}{u}_{rA}\\ u_{rB}\\ u_{rc}\\ u_{rD}\\ u_{rE}\end{array}\right]=U_{om}\left[\begin{array}{c}\cos \left({\mathrm{\ω}}_{o}t\right)\\ cos({\mathrm{\ω}}_{o}t-2\mathrm{\π}/5)\\ \cos ({\mathrm{\ω}}_{o}t-4\mathrm{\π}/5)\\ \cos ({\mathrm{\ω}}_{o}t-6\mathrm{\π}/5)\\ \cos ({\mathrm{\ω}}_{o}t-8\mathrm{\π}/5)\end{array}\right]---\left(10\right)$

In formula, U_omFor output phase voltage amplitude；ω_oFor output voltage angular frequency.

Assume that reference voltage vector is at the Ith sector (now, θ_v=ω_oT, 0≤ω_ot≤π/5).The dutycycle of each vector is calculated by formula (6), And according to the on off state of vector corresponding in Fig. 5, the voltage of O point is by the five phase brachium pontis that can obtain virtual inverse cascade

$\left\{\begin{array}{c}{u}_{AO}=\frac{u_{pn}}{2}(d_{\mathrm{\α}M}+d_{\mathrm{\α}L}+d_{\mathrm{\β}M}+d_{\mathrm{\β}L})\\ u_{BO}=\frac{u_{pn}}{2}(-d_{\mathrm{\α}M}+d_{\mathrm{\α}L}+d_{\mathrm{\β}M}+d_{\mathrm{\β}L})\\ u_{CO}=\frac{u_{pn}}{2}(-d_{\mathrm{\α}M}-d_{\mathrm{\α}L}+d_{\mathrm{\β}M}-d_{\mathrm{\β}L})\\ u_{DO}=-\frac{u_{pn}}{2}(d_{\mathrm{\α}M}+d_{\mathrm{\α}L}+d_{\mathrm{\β}M}+d_{\mathrm{\β}L})\\ u_{EO}=\frac{u_{pn}}{2}(-d_{\mathrm{\α}M}+d_{\mathrm{\α}L}+d_{\mathrm{\β}M}-d_{\mathrm{\β}L})\end{array}\right.---\left(11\right)$

Formula (5) is substituted into formula (11), and abbreviation can obtain

$\left\{\begin{array}{c}{u}_{AO}=k(1+\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+\sin \left({\mathrm{\θ}}_v\right)\]\\ u_{BO}=k\frac{U_{om}}{2}\[(1-\mathrm{\η})\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+(1+\mathrm{\η})\sin \left({\mathrm{\θ}}_v\right)\]\\ u_{CO}=-k\frac{U_{om}}{2}\[(1+\mathrm{\η})\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+(1-\mathrm{\η})\sin \left({\mathrm{\θ}}_v\right)\]\\ u_{DO}=-k(1+\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+\sin \left({\mathrm{\θ}}_v\right)\]\\ u_{EO}=k(1-\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)-\sin \left({\mathrm{\θ}}_v\right)\]\end{array}\right.---\left(12\right)$

In formula,

$k=\frac{1}{sin(4\mathrm{\π}/5)}\frac{1}{\mathrm{\η}\·M+L}---\left(13\right)$

It is each mutually with reference to output phase voltage that each voltage in formula (12) deducts in formula (10), obtains the zero sequence voltage component of each phase voltage:

$\left\{\begin{array}{c}{u}_{rAZ}=u_{AO}-u_{rA}=k(1+\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+\sin \left({\mathrm{\θ}}_v\right)\]-u_{rA}\\ u_{rBZ}=u_{BO}-u_{rB}=k\frac{U_{om}}{2}\[(1-\mathrm{\η})\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+(1+\mathrm{\η})\sin \left({\mathrm{\θ}}_v\right)\]-u_{rB}\\ u_{rCZ}=u_{CO}-u_{rC}=-k\frac{U_{om}}{2}\[(1+\mathrm{\η})\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+(1-\mathrm{\η})\sin \left({\mathrm{\θ}}_v\right)\]-u_{rC}\\ u_{rDZ}=u_{DO}-u_{rD}=-k(1+\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)+\sin \left({\mathrm{\θ}}_v\right)\]-u_{rD}\\ u_{rEZ}=u_{EO}-u_{rE}=k(1-\mathrm{\η})\frac{U_{om}}{2}\[\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_v)-\sin \left({\mathrm{\θ}}_v\right)\]-u_{rE}\end{array}\right.---\left(14\right)$

Obtained by formula (14)

$\begin{array}{c}{u}_{rAZ}-u_{rBZ}={\mathrm{k\ηU}}_{om}\sin (\frac{\mathrm{\π}}{5}-{\mathrm{\θ}}_o)-u_{rAB}\\ ={\mathrm{k\ηU}}_{om}\cos ({\mathrm{\ω}}_{o}t+\frac{3\mathrm{\π}}{10})-2\sin \left(\frac{\mathrm{\π}}{5}\right)U_{om}\cos ({\mathrm{\ω}}_{o}t+\frac{3\mathrm{\π}}{10})\\ =\[k\mathrm{\η}-2\sin \left(\frac{\mathrm{\π}}{5}\right)\]U_{om}\cos (\mathrm{\ω}t+\frac{3\mathrm{\π}}{10})=0\end{array}---\left(15\right)$

In like manner, obtain

$\left\{\begin{array}{c}{u}_{rBZ}-u_{rCZ}=0\\ u_{rCZ}-u_{rDZ}=0\\ u_{rDZ}-u_{rEZ}=0\end{array}\right.---\left(16\right)$

Known by formula (15) and formula (16)

u_rAZ=u_rBZ=u_rCZ=u_rDZ=u_rEZ=u_rZ (17)

With equally, it is possible to release the u in other sectors_rAZ、u_rBZ、u_rCZ、u_rDZAnd u_rEZ, and obtain same formula (17) knot equally Opinion.

Formula (15), (16) and formula (17) illustrate in output voltage when inverse cascade uses space vector modulation in addition to reference voltage, also Containing zero sequence voltage component u_rZ, zero-sequence component u_rZCan be by the amplitude of output reference voltage vector and sector angle θ of sector, place_vReally Fixed.

Analyzed from above, when load be five balance each other load time, neutral point voltage is residual voltage u_rZ, load voltage waveform It is five symmetrical sine waves；When laod unbalance, neutral point voltage there occurs drift, is no longer residual voltage, load electricity Corrugating is five phase asymmetrical voltages.

Owing to center line brachium pontis is directly connected at the neutral point of load, it is possible to directly voltage to neutral u_NOIt is controlled.By formula (7) (17)

u_rX+u_rZ-u_NO=u_XN (18)

Formula (18) illustrates, as long as controlling neutral point voltage u in a suitable approach_NOFor zero-sequence component u_rZ, no matter load what is in State, all can make five phase output voltages is five symmetrical phase reference voltages.

It is positioned at the 1st sector, as a example by output reference voltage is positioned at the Ith sector, it is assumed that virtual inverse cascade center line with input reference current The upper brachium pontis S of brachium pontis_NpDutycycle be d_N, the dutycycle of its lower brachium pontis is 1-d_N.The output DC voltage of the most virtual rectification stage For

u_pn=d_μu_ab+d_γu_ac+d_0ru_aa (19)

According to formula (19) and Fig. 7, the voltage u of center line brachium pontis can be obtained_NO

$\begin{array}{c}{u}_{NO}=\frac{u_{ab}}{2}{d}_{\mathrm{\μ}}{d}_N-\frac{u_{ab}}{2}{d}_{\mathrm{\μ}}(1+d_N)+\\ \frac{u_{ac}}{2}{d}_{\mathrm{\γ}}{d}_N-\frac{u_{ac}}{2}{d}_{\mathrm{\γ}}(1-d_N)+\\ \frac{u_{aa}}{2}{d}_{0r}{d}_N-\frac{u_{aa}}{2}{d}_{0r}(1-d_N)\\ =\frac{u_{pn}}{2}{d}_N+\frac{u_{pn}}{2}(1-d_N)=\frac{u_{pn}}{2}(2d_N-1)\end{array}---\left(20\right)$

Work as u_NO=u_rZTime, can be in the hope of the dutycycle of center line brachium pontis:

$d_N=\frac{u_{rZ}}{u_{pn}}+0.5---\left(21\right)$

In conjunction with the Space Vector Modulation Strategy of five phase matrix converters, five phase six line matrix converters are within a modulation period The sequence of switches is as shown in Figure 8.Dutycycle d in figure₁And d₂It is respectively, d₁=d_μαM+d_μβL+d_μαL+d_μβM, d₂=d_γαM+d_γβL+d_γαL+d_γβM.3 × 5 parts therein switch according to the order of Fig. 8 (a)；When reference input current phasor Be positioned at odd number of sectors (the 1st, 3,5 sector) interior time, center line brachium pontis switch transfer sequence be modulated according to Fig. 8 (b)；When being positioned at When even sectors (the 2nd, 3,6 sector) is interior, it is modulated according to Fig. 8 (c).The switching times that this ensure that switch is minimum, Thus decrease switching loss.

In order to verify validity and the feasibility of put forward control method, in the case of Fig. 9 gives balanced load, use side of the present invention Output five phase load voltage waveform during method, export five phase current waveform and current in middle wire waveform；Figure 10 gives unbalanced load In the case of, use the inventive method time output five phase load voltage waveform, export five phase current waveform and current in middle wire waveform； When the B phase in the case of unbalanced load that gives Figure 11 breaks, output five phase load voltage waveform when using the inventive method, defeated Go out five phase current waveform and current in middle wire waveform.

As shown in Figure 9, when load balance, output voltage and current waveform are the sine wave of symmetry, now output center line bridge Arm electric current is almost nil.By the result figure in contrast Figure 10 and Figure 11, can obtain, along with the increase of laod unbalance degree, The current amplitude of center line brachium pontis becomes big the most accordingly.But, in addition to B phase, remaining 4 phase load voltage waveform is still symmetrical Sinusoidal wave, it is possible to normally to work.

In sum, in the case of load balance and imbalance, this method all can guarantee that the balance of output phase voltage.Thus verify Five phase six line matrix converters value in actual applications.

Although above in conjunction with accompanying drawing, invention has been described, but the invention is not limited in above-mentioned detailed description of the invention, Above-mentioned detailed description of the invention is schematic, and nonrestrictive, those of ordinary skill in the art under the enlightenment of the present invention, In the case of without departing from invention objective, it is also possible to make other form, within these belong to the protection of the present invention.

Claims (4)

1. null1. five phase six line matrix converter control method under a unbalanced load，Wherein，Five phase six line matrix converters are made up of 18 two-way power switch，Three-phase input power and five phase loads are connected by 15 in described 18 power switch，The other three power switch is connected at load neutral point by center line brachium pontis，Wherein arbitrarily input mutually by six of which power switch with export five phases and center line brachium pontis is connected，It is characterized in that: application indirect conversion method，Five phase six line matrix converters are equivalent to virtual AC-DC-AC structure，Described virtual AC-DC-AC structure includes virtual rectification stage and virtual inverse cascade，On this basis，Double Space Vector Modulation strategy to 3 × 5 certain applications therein，And obtain the dutycycle of respective vectors combination，Center line brachium pontis individually uses PWM method to be modulated simultaneously，Analyze、Derive the dutycycle of center line brachium pontis，And the voltage controlling load neutral point is corresponding residual voltage，Then reasonably optimizing 3 × 5 part and the switching sequence of center line brachium pontis，It is minimum for making its switching times within a modulation period.
2. Five phase six line matrix converter control methods under a kind of unbalanced load the most according to claim 1, is characterized in that: the function expression of described dutycycle is:

   Virtual rectification stage duty cycle functions:

   In formula, m_cFor current-modulation ratio；θ_cFor input current sector angle；T_sFor modulation period；T_μ、T_γ、T_0cAnd d_μ、d_γ、d_0cIt is respectively time and the dutycycle of corresponding vector；

   In virtual inverse cascade, the duty cycle functions of five phase brachium pontis is:

   In formula, U_omFor output phase voltage amplitude；θ_vFor angle, output voltage sector；u_pnThe DC voltage exported for virtual rectification stage；M=0.4；L=0.8cos (π/5)；T_{α L}、T_{α M}、T_{β L}、T_{β M}And d_{α L}、d_{α M}、d_{β L}、d_{β M}It is respectively action time and the dutycycle of respective vectors；η is the relative ratios of the middle vector on same direction and big vector；In order to ensure that exporting five phase voltage waveforms is sine wave, η should be equal to 0.618；

   Wherein, the duty cycle functions of the vectorial combination of described 3 × 5 parts is:

   。
3. Five phase six line matrix converter control methods under a kind of unbalanced load the most according to claim 1, is characterized in that: described zero sequence voltage component is

   In described virtual inverse cascade, the duty cycle functions of center line brachium pontis is:

   Wherein, u_rZFor zero sequence voltage component, u_maxFor exporting the maximum of five phase voltages.
4. Five phase six line matrix converter control methods under a kind of unbalanced load the most according to claim 1, is characterized in that: be further:

   (1) on the equivalent AC-DC-AC architecture basics of five phase six line matrix converters, according to space vector modulation algorithm, in determining a switch periods, each vector duty cycle d of virtual rectification stage_μ、d_γ、d_0cEach vector duty cycle d with five phase brachium pontis in virtual inverse cascade_{α L}、d_{α M}、d_{β L}、d_{β M}、d_0v；Each vector duty cycle of two-stage is combined dutycycle d obtaining 3 × 5 each vectorial combinations of part_{μα L}、d_{μα M}、d_{μβ L}、d_{μβ M}、d_{γα L}、d_{γα M}、d_{γβ L}、d_{γβ M}And d₀；

   (2) center line brachium pontis uses PWM method, and its dutycycle is d_N, controlling load neutral point voltage is corresponding residual voltage u_rZSo that it is under unbalanced load, obtain the load voltage of symmetry；

   (3) 3 × 5 parts of five phase six line matrix converters and the on off state of center line brachium pontis are optimized combination, the reasonable arrangement sequence of switches, it is ensured that the switching times in the modulation period is minimum.