KR20180026070A - Driving device for dual parallel motors - Google Patents

Abstract

The present invention relates to a driving apparatus for a double parallel motor which achieves miniaturization, low cost, extended service life, and high power density of a power conversion system by eliminating a DC-link capacitor. The driving apparatus for a double parallel motor comprises: a rectifier including a plurality of bidirectional switches and electrically connecting a three-phase AC power source to a fictitious DC-link through at least a part of the plurality of bidirectional switches; and an inverter including a plurality of unidirectional switches and electrically connecting the fictitious DC-link to a double parallel motor through at least a part of the plurality of unidirectional switches.

Description

TECHNICAL FIELD [0001] The present invention relates to a driving apparatus for a dual parallel motor,

The present invention relates to a driving apparatus for a dual parallel electric motor.

The basic form of a dual motor drive system is that each motor is connected to two inverters sharing a DC link (DC link). The two inverters control the motor independently by converting the DC voltage to an AC voltage of the required frequency and magnitude. Since a dual motor drive system using these two inverters causes size and cost problems, a dual motor drive system using one inverter has been proposed in various forms.

A dual motor drive system using one inverter can be composed of various topologies such as a 9-switch inverter, a 4-leg inverter, a 5-leg inverter, and a 2-level inverter.

The 9-switch inverter has three legs, each leg consisting of three switches. These inverters can generate two independent three-phase AC output voltages, each output being output between the upper and middle switches of the legs, and between the lower and middle switches. In addition, the two motors are respectively connected to the other output lines of the legs (Non-Patent Document 1).

The four-leg inverter uses eight switches and can generate two three-phase ac output voltages using the neutral stage of the dc stage. Two motors are connected to two legs of the four-leg inverter, and the other phase of the two motors is commonly connected to the neutral stage of the dc stage (Non-Patent Document 2).

The five-leg inverter uses ten switches and can generate two three-phase ac output voltages using common legs. Two motors are connected to two legs respectively and the remaining phase is connected to a common leg (Non-Patent Document 3).

The three topologies described above can drive two motors independently while reducing the number of switches. However, when the number of switches is reduced, a non-general control method considering the constraint and the distortion of the output caused by the dual motor control is used. In addition, these topologies have the disadvantage that they are not suitable for mass production because they are modified versions of two-level inverters.

In a dual-motor drive system using a general two-level inverter, the driving characteristics of the motor vary depending on how the two motors are connected to the inverter. In the case of a system in which two motors are connected in series, one phase of two motors is directly connected. In this system, the two motors can operate at different speeds and can be operated under different load conditions. However, pulsation occurs in the torque component including the current of each motor as a harmonic (Non-Patent Document 4).

In a system in which two motors are connected in parallel, two motors are connected in parallel with the two-level inverter. In such a system, two motors are driven at synchronous speeds and can be operated under different load conditions (Non-Patent Document 5).

The above-mentioned double-motor drive systems use a power conversion device including a DC short-circuit capacitor. Electrolytic capacitors act as a buffer for power transfer between input and output, so they must be large enough to accommodate all the power they need. Therefore, not only the electrolytic capacitor requires a lot of space, but also it is known that it is a main factor that shortens the lifetime of the entire power conversion system due to the rapid decrease of the capacitance according to the operating time at the high temperature operation. As a result, the DC short-circuit capacitor is an element that hinders downsizing, cost reduction, and service life of the power conversion system.

 F. Gao, L. Zhang, D. Li, P. C. Loh, Y. Tang, and H. Gao, "Optimal Pulse Width Modulation of the Nine-Switch Converter," IEEE Trans. Power Electron., Vol. 25, No. 9, pp. 2331-2343, Sep. 2010.  S. Ito, T. Moroi, Y. Kubo, and K. Matsuse, "Independent control of two permanent-magnet synchronous motors fed by a four-leg inverter," IEEE Trans. Ind. Appl., Vol. 51, No. 1, pp. 753-760, Jan.-Feb. 2015.  C. S. Lim, N. A. Rahim, W. P. Hew, and E. Levi, "Model predictive control of a two-motor drive with five-leg-inverter supply," IEEE Trans. Ind. Electron., Vol. 60, No. 1, pp. 54-65, Jan. 2013.  Y. Kim and J.-I. Ha, "Novel topology and control of single inverter system for two permanent magnet synchronous machines," in Proc. APEC Conf., Pp. 833-837, Mar. 2014.  Y. Lee and J.-I. Ha, "Control method for mono inverter dual parallel surface-mounted permanent-magnet synchronous machine drive system," IEEE Trans. Ind. Electron., Vol. 62, No. 10, pp. 6096-6107, Oct. 2015.

SUMMARY OF THE INVENTION A technical problem to be solved is to provide a driving apparatus for a dual-parallel electric motor which achieves miniaturization, low cost, extended service life and high power density of a power conversion system by eliminating a DC short capacitor, There is.

A driving apparatus for a dual parallel motor according to an exemplary embodiment of the present invention includes a plurality of bidirectional switches, and a three-phase AC power source is electrically connected to a fictitious DC-Link through at least a part of the plurality of bidirectional switches, ; And an inverter that includes a plurality of unidirectional switches and electrically connects the virtual direct current stage with the bi-parallel electric motor through at least a part of the plurality of unidirectional switches.

The plurality of bidirectional switches including a first upper bidirectional switch, a first lower bidirectional switch, a second upper bidirectional switch, a second lower bidirectional switch, a third upper bidirectional switch, and a third lower bidirectional switch, The bidirectional switch and the first lower-end bidirectional switch are connected in series to correspond to the first rectifier leg, the second upper bidirectional switch and the second lower-end bidirectional switch are connected in series to correspond to the second rectifier leg, The three upper bidirectional switches and the third lower bidirectional switches may be connected in series to correspond to the third rectifier legs.

Wherein the plurality of unidirectional switches comprises a first upper unidirectional switch, a first lower unidirectional switch, a second upper unidirectional switch, a second lower unidirectional switch, a third upper unidirectional switch, and a third lower unidirectional switch, The first unidirectional switch and the first lower unidirectional switch are connected in series to correspond to the first inverter leg, the second upper unidirectional switch and the second lower unidirectional switch are connected in series to correspond to the second inverter leg, The unidirectional switch and the third lower unidirectional switch may be connected in series to correspond to the third inverter leg.

The driving device of the double parallel motor may further include a first current sensor disposed between the inverter and the main electric motor of the double parallel electric motor.

The current sensor may be a shunt resistor.

The driving device of the double parallel-type motor may further include a second current sensor positioned between the three-phase AC power source and the rectifier.

The driving apparatus of the double parallel-arm motor includes: a first dq coordinate transforming unit for transforming the input phase current detected by the second current sensor into dq axis coordinates; And an input current vector position detector for deriving the phase angle of the input current vector, which is a vector of the input phase current converted by the coordinate transformation, and the positional area in the first vector diagram.

The driving apparatus of the double parallel-type motor may further include a duty ratio calculating unit for calculating a duty ratio of two bidirectional switches among the plurality of bidirectional switches according to a phase angle and a position area of the input current vector.

The driving apparatus of the double parallel type motor may further include a virtual DC voltage calculation unit for calculating a virtual DC voltage using the magnitude of the input line voltage and the duty ratio.

The driving apparatus for a dual parallel motor includes an output side d-axis command current calculator for calculating an output d-axis command current by using a rotational speed difference and a phase angle difference between a main motor and a sub motor of the dual parallel motor; And an output-side q-axis command current calculator for calculating an output-side q-axis command current using the difference between the sensed rotational speed of the main motor and the command speed.

The driving apparatus of the double parallel-arm motor includes: a second dq coordinate converter for converting the output phase current detected by the first current sensor into dq axis coordinates; And an output side command voltage calculation unit for calculating an output side command voltage using the difference between the coordinate of the output phase current, the output side d axis command current and the output side q axis command current and the phase angle information.

The driving apparatus of the double parallel-type motor may further include a modulated signal generating unit for generating a rectified modulated signal using the duty ratio.

The modulation signal generator may generate an inverter modulation signal using the output side command voltage, the duty ratio, and the virtual DC voltage.

The driving device of the double parallel-type motor may further include a PWM signal generator for generating a rectifier PWM signal by comparing the rectified modulated signal with a carrier wave and for comparing the inverter modulated signal with a carrier wave to generate an inverter PWM signal.

And a gate driver controlling the plurality of bidirectional switches using the rectifier PWM signal and controlling the plurality of unidirectional switches using the inverter PWM signal.

The driving apparatus for a double parallel-type motor according to the present invention can provide a specific control system for the power conversion system while achieving miniaturization, low cost, extended service life and high power density of the power conversion system by eliminating the DC short-circuit capacitor.

1 is a view for explaining a driving apparatus for a dual parallel motor according to an embodiment of the present invention.
2 is a view for explaining a control system of a driving apparatus for a dual parallel motor according to an embodiment of the present invention.
3 is a space vector diagram for explaining a control method for a rectifier according to an embodiment of the present invention.
4 is a space vector diagram for explaining a control method for an inverter according to an embodiment of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. Therefore, the above-mentioned reference numerals can be used in other drawings.

In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings. In the drawings, the size and thickness may be exaggerated to clearly represent the layers and regions.

1 is a view for explaining a driving apparatus for a dual parallel motor according to an embodiment of the present invention.

Referring to FIG. 1, a driving apparatus 10 for a double parallel motor according to an embodiment of the present invention includes a rectifier 100 and an inverter 300.

The rectifier 100 includes a plurality of bidirectional switches and electrically connects the three-phase AC power source 90 with a fictitious DC-Link 200 through at least a part of a plurality of bidirectional switches.

A plurality of two-way switch comprises a top first two-way switch _{(S aP, S aP ')} , a first bottom of a two-way switch _{(S aN, S aN')} , the second upper-way switch _{(S bP, S bP ')} , the second lower Directional switch S _bN , S _bN ', a third upper bidirectional switch S _cP , S _cP ', and a third lower bidirectional switch S _cN , S _cN '. The plurality of bidirectional switches may include six bidirectional switches each consisting of a combination of twelve unidirectional switches (IGBTs) and anti-parallel diodes.

The top of the bidirectional switch _{1 (S aP, S aP '} ) and a first bottom of a two-way switch (S _aN, S _aN') are connected in series and corresponding to the first rectifier leg, second upper two-way switch (S _bP, S _bP ') and a second lower end two-way switch (S _bN, S _bN') are connected in series and corresponding to the second rectifier leg, and the third upper-way switch (S _cP, S _cP ') and the third lower-way switch ( S _cN , S _cN ') may be connected in series to correspond to the third rectifier leg.

The virtual DC stage 200 refers to the portion where the DC short capacitor is located in the prior art. That is, since the dc capacitor is removed from the driving apparatus 10 of the double parallel-type motor according to the embodiment of the present invention, the virtual dc stage 200 is connected between the output terminal of the rectifier 100 and the inverter 300 And the input terminal of the inverter circuit. The voltage of the virtual DC terminal 200 can be calculated and used for generating a modulated signal, which will be described later in detail with reference to FIG.

The three-phase AC power source 90 can be modeled with input phase voltages V _a , V _b , and V _c and input phase currents I _a , I _b , and I _c to eliminate voltage and current ripple The filter units L _f and C _f . The filtered three-phase AC power source 90 may be electrically connected to the virtual DC terminal 200 according to the current path formed according to the on / off states of the plurality of bidirectional switches. The ON / OFF control of a plurality of bidirectional switches will be described later in detail with reference to Fig.

The inverter 300 includes a plurality of unidirectional switches, and electrically connects the virtual DC terminal 200 to at least one of the plurality of unidirectional switches with the bi-parallel motor.

The plurality of unidirectional switches includes a first upper unidirectional switch S _AP , a first lower unidirectional switch S _AN , a second upper unidirectional switch S _BP , a second lower unidirectional switch S _BN , (S _CP ), and a third lower unidirectional switch (S _CN ).

The first upper unidirectional switch S _AP and the first lower unidirectional switch S _AN are connected in series to correspond to the first inverter leg and the second upper unidirectional switch S _BP and the second lower unidirectional switch S _BN May be connected in series to correspond to the second inverter legs, and the third upper unidirectional switch S _CP and the third lower unidirectional switch S _CN may be connected in series to correspond to the third inverter leg.

The dual parallel motors may include a main electric motor 410 and a sub electric motor 420 connected in parallel with each other. The phase A of each of the main electric motor 410 and the sub electric motor 420 is connected to the first inverter leg so that the output phase currents I _A1 and I _A2 can flow through the primary inverter 410 and the secondary electric motor 420, And the phase C of each of the main electric motor 410 and the sub electric motor 420 is connected to the second inverter leg so that the output phase currents I _B1 and I _B2 can flow through the third inverter legs, And the output phase currents (I _C1 , I _C2 ) can flow through each of them.

The drive device 10 of the bi-parallel motor may include a first current sensor 310 located between the inverter 300 and the main motor 410, wherein the first current sensor 310, May be a shunt resistor (R _{A, Shunt} , R _{B, Shunt} ) (see FIG. 2). Current measurement using a shunt resistor (R _{A, Shunt} , R _{B, Shunt} ) is advantageous in that it can further reduce the cost of the system.

The main electric motor 410 and the sub electric motor 420 may be surface-mounted permanent-magnet synchronous motors (SPMSM), respectively. Various other permanent magnet synchronous motors may be employed as the main electric motor 410 and the sub electric motor 420.

The main electric motor 410 and the sub electric motor 420 are driven at a synchronous speed and can output different torques, respectively.

2 is a view for explaining a control system of a driving apparatus for a dual parallel motor according to an embodiment of the present invention.

A back-to-back converter including a capacitor in a DC stage can separately control the rectification stage and the inverter stage. For example, the grid side inverter of the grid-connected inverter maintains the DC voltage constant and the power side rectifier can control the appropriate power. However, the double parallel drive system of a permanent magnet synchronous motor without a DC capacitor requires a more stable load due to the absence of a DC capacitor and has a low dynamic response characteristic. Therefore, it is necessary to develop a stable control system through control of input and output. Dual parallel drive systems of permanent magnet synchronous motors without dc capacitors must produce high quality three-phase voltage and current, regardless of load.

2, a driving apparatus 10 for a dual parallel motor according to an exemplary embodiment of the present invention includes a rectifier 100, an inverter 300, a first current sensor 310, a second current sensor 110, A first dq coordinate conversion unit 120, an input current vector position detection unit 130, a duty ratio calculation unit 140, a virtual DC voltage calculation unit 150, an output d axis current calculation unit 330, A second dq coordinate transformation unit 320, an output side command voltage calculation unit 350, a modulation signal generation unit 510, a PWM signal generation unit 520, and a gate driver 530. The axis command current calculation unit 340, . ≪ / RTI >

The first current sensor 310 may be located between the inverter 300 and the main motor 410 of the bi-parallel motor. As described above, the first current sensor 310 may include a shunt resistor.

The second current sensor 110 may be positioned between the three-phase AC power source 90 and the rectifier 100. The second current sensor 110 may measure the input phase currents I _a , I _b , and I _c and transmit the sensing value to the first dq coordinate converter 120.

The first dq coordinate converter 120 may convert the input phase currents I _a , I _b , and I _c detected from the second current sensor 110 into dq axis coordinates. Where I _d is the coordinate transformed d-axis current value, and I _q is the coordinate transformed q-axis current value.

) 및 제1 벡터 다이어그램에서의 위치 영역(N)을 도출할 수 있다(도 3 참조).The phase angle of the input current vector position detector 130 is an input phase current coordinate conversion (I _a, I _b, I _c) vector the input current vector (131 of the

And the location area N in the first vector diagram (see FIG. 3).

) 및 위치 영역(N)에 따라 복수의 양방향 스위치 중 2 개의 양방향 스위치의 듀티비(duty ratio)(d_x, d_y)를 계산할 수 있다. 듀티비(d_x, d_y)의 산출에 대해서는, 도 3을 참조하여 더 상세히 후술한다.The duty ratio calculator 140 calculates the duty ratio of the input current vector 131

The duty ratio (d _x , d _y ) of two bidirectional switches among a plurality of bidirectional switches can be calculated according to the positional area N and the positional area N. [ The calculation of the duty ratio (d _x , d _y ) will be described later in more detail with reference to Fig.

The virtual DC voltage calculation unit 150 can calculate the virtual DC voltage V _DC using the magnitude and the duty ratio of the input line voltage. The calculation of the virtual direct current voltage V _DC will be described later in more detail with reference to Fig.

,

) 차이 및 위상각(

,

) 차이를 이용하여 출력측 d축 지령 전류(

)를 계산할 수 있다.The output-side d-axis command current calculator 330 calculates the rotational speed of the main motor 410 and the sub-motor 420 of the dual-

,

) Difference and phase angle (

,

) Difference, the output d-axis command current (

) Can be calculated.

)와 지령 속도(

)의 차이를 이용하여 출력측 q축 지령 전류(

)를 계산할 수 있다.The output-side q-axis command current calculator 340 calculates the q-axis command current

) And command speed (

), The output q-axis command current (

) Can be calculated.

The second dq coordinate transformer 320 may convert the output phase currents I _A1 , I _B1 , and I _C1 detected by the first current sensor 310 into dq axis coordinates. Here, I _d1 is the coordinate-converted d-axis current value, and I _q1 may be the coordinate-converted q-axis current value.

) 및 출력측 q축 지령 전류(

)의 차이 및 위상각 정보를 이용하여 출력측 지령 전압을 계산할 수 있다.The output-side command voltage calculation unit 350 calculates the output-side command voltage (I _A1 , I _B1 , I _C1 ) and the output-side d-axis command current

) And output side q-axis command current (

) And the phase angle information can be used to calculate the output side command voltage.

,

), 듀티비(d_x, d_y), 및 가상 직류단 전압(V_DC)을 이용하여 인버터 변조 신호를 생성할 수 있다.The modulation signal generator 510 may generate a rectifier modulated signal using the duty ratio (d _x , d _y ). Further, the modulated signal generating section 510 generates the modulated signal

,

), The duty ratio (d _x , d _y ), and the virtual DC voltage (V _DC ).

The PWM signal generator 520 may generate a rectifier PWM signal by comparing the rectifier modulation signal with a carrier wave, and may generate an inverter PWM signal by comparing the inverter modulation signal with a carrier wave. In one embodiment, the carrier wave can be a triangular file.

Through this modulation scheme, the maximum value of the input AC voltage can be transmitted to the virtual DC stage 200.

The gate driver 530 may control the plurality of bidirectional switches of the rectifier 100 using the rectifier PWM signal and may control the plurality of unidirectional switches of the inverter 300 using the inverter PWM signal.

3 is a space vector diagram for explaining a control method for a rectifier according to an embodiment of the present invention.

The modulation technique of the rectifier 100 of the dual parallel drive system of a permanent magnet synchronous motor without a DC capacitor is such that the voltage of the virtual DC stage 200 is formed to the maximum value of the input AC voltages V _a , V _b , and V _c So that the unit power factor of the input side and the sinusoidal currents (I _a , I _b , I _c ) can be ensured. The voltage of the virtual direct current stage 200 is generated in accordance with the switching state of the plurality of bidirectional switches of the rectifier 100. The rectifier 100 can be operated such that one upper bidirectional switch and one lower bidirectional switch are turned on at any moment.

Referring to FIG. 3, a first vector diagram for control of rectifier 100 is shown. Referring to the first vector diagram, six effective vectors CS1, CS2, CS3, CS4, CS5, and CS6 correspond to six corresponding positional areas (sector 1, sector 2, sector 3, sector 4, sector 5, sector 6 ).

The effective vectors CS1, CS2, CS3, CS4, CS5 and CS6 mean that the upper bidirectional switch and the lower bidirectional switch are on different states. Therefore, in this embodiment, the effective vector CS1, which is the case when the first upper bidirectional switch _SaP , _SaP 'and the third lower-order bidirectional switch S _cN , S _cN ' are turned on, S _bP, S _bP ') and the third lower-way switch (S _cN, S _cN') is on the effective vector (CS2), the second upper-way switch (S _bP, S _bP 'if used) and the first lower-way that the switch (S _aN, S _aN ') is on the effective vector (CS3), the third upper-way switch (S _cP, S _cP If') and a first bottom of the two-way switch (S _aN, S _aN ') on If the effective vector (CS4), the upper three-way switch (S _cP, S _cP ') and a second lower end two-way switch (S _bN, S _bN') is a valid vector (CS5), and a first upper case being turned on as an effective vector (CS6) which when the two-way switch (S _{aP, aP} S ') and the second bottom two-way switch (S _{bN, bN} S') being turned on, the effective vector may be a total of six.

A null vector means a case where the upper bidirectional switch and the lower bidirectional switch are on the same phase. Therefore, in this embodiment, the null vector (Null), the first top two-way switch (S _aP, S _aP ') and a first bottom of a two-way switch (S _aN, S _aN') is when turned on, the second upper-way switch (S _bP, S _bP ') and a second lower end two-way switch (S _bN, S _bN') is when turned on, and the third top of the two-way switch (S _cP, S _cP ') and the third lower-way switch (S _cN , S _cN ') are turned on, and there can be three in total.

When an effective vector is applied, power is transferred to a virtual DC stage, and when a null vector is applied, no voltage is applied to a virtual DC stage.

)이 위치 영역(sector 1)에 위치하는 경우, 입력 전류 벡터(131)에 근접한 2 개의 유효 벡터(CS1, CS6)를 인가할 수 있다. 2 개의 유효 벡터(CS1, CS6)를 인가한다는 것은, 유효 벡터(CS1)에 대응하는 제1 상단 양방향 스위치(S_aP, S_aP') 및 제3 하단 양방향 스위치(S_cN, S_cN')를 일정 시간 범위로 온 시키고, 유효 벡터(CS6)에 대응하는 제1 상단 양방향 스위치(S_aP, S_aP') 및 제2 하단 양방향 스위치(S_bN, S_bN')를 일정 시간 범위로 온 시킨다는 의미이다.For example, the phase angle of the input current vector 131 (or command current vector)

Is located in the position area (sector 1), two effective vectors CS1 and CS6 close to the input current vector 131 can be applied. Applying the two valid vectors CS1 and CS6 means that the first upper bidirectional switches _SaP and _SaP 'and the third lower half bidirectional switches S _cN and S _cN ' corresponding to the effective vector CS1 Means that the first upper bidirectional switch _SaP and _SaP 'and the second lower two-way switch S _bN and S _bN ' corresponding to the effective vector CS6 are turned on for a predetermined time period to be.

In this case, the first top two-way switch (S _aP, S _aP ') keeps the on state for a period, and the third lower-way switch (S _cN, S _cN') and a second lower end two-way switch (S _bN, S _bN ') will be modulated according to the duty ratio (d _x, d _y) for each one period.

The duty ratio (d _x , d _y ) can be determined according to the following equation (1).

[Equation 1]

The duty ratios (d _x , d _y ) in Equation (1) can be expressed by Equation (2) and Equation (3) below.

&Quot; (2) "

&Quot; (3) "

,

,

는 각각 센싱된 입력 상 전류(또는 지령 상 전류)이며,

는 기본파 각주파수를 의미한다.In Equation (2)

,

,

Is an input phase current (or command phase current) respectively sensed,

Means the fundamental wave frequency.

은 듀티비(d_x, d_y)와 입력 측 선간 전압의 곱으로 아래 수학식 4와 같이 계산된다.The average value of the DC voltage applied to the virtual DC stage 200

Is calculated by the following formula (4) as the product of the duty ratio (d _x , d _y ) and the input-side line voltage.

&Quot; (4) "

는 역률 값이다.At this time,

Is the power factor value.

A modulation scheme of the same principle can be applied even when the input current vector 131 is located in another position area (sector 2, sector 3, sector 4, sector 5, sector 6) in addition to the above-described position area (sector 1) have.

4 is a space vector diagram for explaining a control method for an inverter according to an embodiment of the present invention.

Referring to Figure 4, a second vector diagram for control of the inverter 300 is shown. Referring to the second vector diagram, there are shown six valid vectors (VS1, VS2, VS3, VS4, VS5, VS6) and two zero vectors (VS0, VS7). This spatial vector modulation technique may be similar to the modulation scheme of a two-level voltage source inverter.

The effective vector VS1 is set such that when the first upper unidirectional switch S _AP , the second lower unidirectional switch S _BN and the third lower unidirectional switch S _CN are on, a one-way switch (S _AP), the second upper-way switch (S _BP), the third lower-way switch (S _CN) is on the case, the effective vector (VS3) of the first bottom-way switch (S _aN) state, the second When the upper unidirectional switch S _BP and the third lower unidirectional switch S _CN are in an on state, the effective vector VS4 is divided into a first lower unidirectional switch S _AN , a second upper unidirectional switch S _BP , When the upper unidirectional switch S _CP is in the on state, the effective vector VS5 is connected to the first lower unidirectional switch S _AN , the second lower unidirectional switch S _BN and the third upper unidirectional switch S _CP If the oN state of the effective vector (VS6) is a case where the first upper one-way switch (S _AP), the second lower-way switch (S _BN), the third upper-way switch (S _CP) on state May Michal.

The zero vector VS0 is set such that when the first lower unidirectional switch S _AN , the second lower unidirectional switch S _BN and the third lower unidirectional switch S _CN are on, It may mean that the unidirectional switch (S _AP ), the second upper unidirectional switch (S _BP ) and the third upper unidirectional switch (S _CP ) are on.

)은 출력측 지령 전압(

,

)에 의해 결정될 수 있다. 공간 벡터 변조 기법에 의한 2 개의 변조 신호

,

는 아래 수학식 5 및 수학식 6과 같이 결정될 수 있다. 이때 수학식 7을 참조할 수 있다.The magnitude and phase angle of the command voltage vector 351 (

) Is the output side command voltage

,

). ≪ / RTI > Two modulated signals by spatial vector modulation

,

Can be determined according to the following equations (5) and (6). Here, Equation (7) can be referred to.

&Quot; (5) "

&Quot; (6) "

&Quot; (7) "

,

,

는 각각 전동기의 지령 상 전압으로서, 지령 전압 벡터(351)의 역변환 값일 수 있다.At this time,

,

,

May be an inverse conversion value of the command voltage vector 351 as command voltage of the electric motor, respectively.

In addition to the current control method described above, direct torque control and torque prediction control can be performed on the inverter 300 side. In the case of the direct torque control, the stator magnetic flux and torque can be estimated using the current sensed on the main motor 410 side. The command voltage vector to be applied in the switching table can be selected by comparing the estimated magnetic flux, the error between the torque, the command magnetic flux and the command torque with the hysteresis bandwidth. Unlike direct torque control, torque prediction control does not use a switching table. The torque prediction control can be mathematically analyzed to obtain a desired command voltage vector by calculating the relationship between the torque, the magnetic flux, and the output voltage of the voltage source inverter stage. After obtaining the command voltage vector, the modulation of the inverter 300 proceeds in the same manner as the command voltage generating method in the current control method. Two modulated signals are generated using the command voltage, the virtual direct-current voltage calculated at the rectifier 100 side and the duty ratio, and the PWM signal for modulating the voltage source inverter can be generated by comparing the modulated signal with the triangular wave.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are illustrative and explanatory only and are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention as defined by the appended claims. It is not. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Driving device of double parallel motor
100: rectifier
200: virtual direct current stage
300: Inverter

Claims (15)

A rectifier including a plurality of bidirectional switches and electrically connecting the three-phase AC power source to a fictitious DC-Link through at least a part of the plurality of bidirectional switches; And
And an inverter that includes a plurality of unidirectional switches and electrically connects the virtual direct current stage to the double parallel electric motor through at least a portion of the plurality of unidirectional switches
Drive device for a double parallel motor. The method according to claim 1,
The plurality of bidirectional switches including a first upper bidirectional switch, a first lower bidirectional switch, a second upper bidirectional switch, a second lower bidirectional switch, a third upper bidirectional switch, and a third lower bidirectional switch,
Wherein the first upper bidirectional switch and the first lower bidirectional switch are connected in series to correspond to the first rectifier leg,
The second upper bidirectional switch and the second lower bidirectional switch being connected in series to correspond to the second rectifier leg,
Wherein the third upper bidirectional switch and the third lower bidirectional switch are connected in series and corresponding to the third rectifier leg,
Drive device for a double parallel motor. 3. The method of claim 2,
The plurality of unidirectional switches including a first upper unidirectional switch, a first lower unidirectional switch, a second upper unidirectional switch, a second lower unidirectional switch, a third upper unidirectional switch, and a third lower unidirectional switch,
The first upper unidirectional switch and the first lower unidirectional switch are connected in series to correspond to the first inverter leg,
The second upper unidirectional switch and the second lower unidirectional switch are connected in series to correspond to the second inverter leg,
Wherein the third upper unidirectional switch and the third lower unidirectional switch are connected in series and corresponding to the third inverter leg,
Drive device for a double parallel motor. The method of claim 3,
Further comprising a first current sensor located between the inverter and the main electric motor of the bi-parallel motor
Drive device for a double parallel motor. 5. The method of claim 4,
Wherein the current sensor is a shunt resistor,
Drive device for a double parallel motor. 5. The method of claim 4,
And a second current sensor positioned between the three-phase AC power source and the rectifier
Drive device for a double parallel motor. The method according to claim 6,
A first dq coordinate converter for converting an input phase current detected by the second current sensor into dq axis coordinates; And
Further comprising an input current vector position detector for deriving a phase angle of an input current vector, which is a vector of the input phase current converted by the coordinate transformation, and a positional area in the first vector diagram
Drive device for a double parallel motor. 8. The method of claim 7,
And a duty ratio calculator for calculating a duty ratio of two bidirectional switches of the plurality of bidirectional switches according to a phase angle and a position area of the input current vector
Drive device for a double parallel motor. 9. The method of claim 8,
And a virtual DC voltage calculation unit for calculating a virtual DC voltage using the magnitude of the input line voltage and the duty ratio
Drive device for a double parallel motor. 10. The method of claim 9,
An output-side d-axis command current calculator for calculating an output-side d-axis command current using a rotational speed difference and a phase angle difference between the main motor and the sub-motor of the dual parallel motor;
And an output-side q-axis command current calculator for calculating an output-side q-axis command current using the difference between the sensed rotational speed of the main motor and the command speed
Drive device for a double parallel motor. 11. The method of claim 10,
A second dq coordinate converter for converting an output phase current detected by the first current sensor into dq axis coordinates; And
And an output-side command voltage calculation unit for calculating an output-side command voltage using the difference between the coordinate-converted output phase current, the output-side d-axis command current and the output-side q-axis command current and phase angle information
Drive device for a double parallel motor. 12. The method of claim 11,
And a modulation signal generator for generating a rectifier modulation signal using the duty ratio
Drive device for a double parallel motor. 13. The method of claim 12,
Wherein the modulation signal generator generates an inverter modulation signal using the output side command voltage, the duty ratio, and the virtual DC voltage,
Drive device for a double parallel motor. 14. The method of claim 13,
Further comprising a PWM signal generator for generating a rectifier PWM signal by comparing the rectifier modulated signal with a carrier wave and for comparing the inverter modulated signal with a carrier wave to generate an inverter PWM signal,
Drive device for a double parallel motor. 15. The method of claim 14,
Further comprising a gate driver controlling the plurality of bidirectional switches using the rectifier PWM signal and controlling the plurality of unidirectional switches using the inverter PWM signal
Drive device for a double parallel motor.

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