TW200919939A - Switching method of a matrix converter and a controlling system thereof - Google Patents

Abstract

A switching method and a controlling system thereof are disclosed. The controlling system is used to control a matrix converter to drive a motor. The matrix converter comprises a plurality of switches. The method comprises following steps: receiving an input voltage and an order current; determining a value of an emulated DC-link voltage; determining a switching strategy for a virtual switch of a virtual converter and a virtual current transformer; determining a switching strategy for the plurality of switches; and switching the plurality of switches to receive different values of the emulated DC-link voltage.

Description

200919939 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to a control system, particularly a DC link voltage value of a converter output to control a motor control system.夂轱 【Prior Art】 Γ # For today's control motor system, it is taught that it can be efficient and = control space for space. Therefore, the control system with matrix converter is the requirement. And because the matrix converter also has the advantages of small current wave, good efficiency, good sin, long life and high temperature resistance, the matrix converter has been widely used in the control system of the control motor. ^ In the prior art, the architecture of the matrix converter is shown in Figure ,, Figure! The actual architectural diagram of the matrix converter. The matrix converter 2 is a three-phase three-phase converter composed of nine solid-state power components. These solid-state power components must have a current bi-directional function, which is commonly referred to as a 2-way AC switch (or four-quadrant switch). Therefore, the nine solid state power elements are regarded as the switching elements S11 to S33 of the matrix converter 20. The control system determines the electric power to be rotated by the matrix converter 20 via the switching elements S11 to S33, thereby controlling the operation mode such as the rotational speed of the motor. & In the prior art, the switching methods commonly used by the matrix converter 20 can be classified into two categories. One of them is a switching method of the switching elements S11 to S33 by using a high-frequency switching function. This method 200919939

It is necessary to accurately calculate the on-time of each of the switching elements SI 1 to S33 in the matrix converter 2, and to instantaneously excite the solid-state power elements. However, if the matrix converter utilizes the high-frequency switching function method, a large number of operations need to be processed immediately to determine the switching mode of the switching elements S11 to S33. This will increase the burden on the control system. Another switching method in the prior art is space vector modulation. This method switches the switching elements S11 to S33 in accordance with the required input current and output voltage waveform. If the matrix converter applies the spatial orientation modulation method, the angle of the space vector must still be determined according to the parameters of the motor, and the calculation is not easy. This method also increases the burden on the control system. On the other hand, the method of switching the virtual DC link voltage in the prior art is exactly the same as the switching pattern of a three-phase rectifier. As shown in Fig. Μ and f 2B, the schematic diagram of the three-phase input voltage of the 2A system is shown as a schematic diagram of the virtual DC link voltage of the prior art. It can be seen from Fig. 2B that after the matrix converter 2G inputs the three-phase input voltage, the obtained DC link voltage value varies between 866.866VPk and Vpk of the input voltage. The peak value of the voltage in the basin. The switch switching pattern is every 6G. Phase angle change: The mother-to-switch is turned on 12 turns. . Using the highest voltage range ', but in the motor, at low speeds, the phase two output currents, thus making the motor have a larger torque (Torque Ripple). To improve the above problem, the switching speed of the component must be 'but the switching frequency is increased, and the switching loss is increased. Systems and methods that will generate the controllers Therefore, a new control matrix transformation needs to be invented to solve the problems of the prior art. SUMMARY OF THE INVENTION The main object of the present invention is to provide a control system having the effect of controlling the voltage value of a virtual DC link output from a matrix converter. To achieve the above objectives, the control system of the present invention includes a matrix converter, an input command terminal, a switching selection module, a current sensing module, and a commutation logic circuit. The matrix converter has switching elements and can be considered to include virtual converters and virtual converters. The input command terminal is used to input a current command to control the matrix converter. The matrix converter is able to control the motor according to the input voltage and current commands. The switching selection module and the current sensing module are used to control the switching elements in the matrix converter, that is, the switching between the virtual converter and the virtual converter to output different virtual DC link voltages. The commutation logic circuit is used to protect the switching elements of the matrix converter, which will cause the components to be damaged when the matrix converter is quickly switched. Another main object of the present invention is to provide a switching method. The switching method of the present invention comprises the steps of: receiving an input voltage and a current command; determining a virtual switching mode in the virtual converter; determining a virtual switching mode in the virtual converter; determining a switching mode of the switching element; The three-step commutation method switches the switching elements to obtain different DC link voltage values. [Embodiment] In order to enable the reviewing committee to better understand the technical contents of the present invention, a preferred embodiment will be described below. 200919939 Please refer to FIG. 3 for an architectural diagram of the control (four) system of the present invention. The control system of the field is a system with a matrix converter 20 for outputting different DC link voltage values to control the motor %. The motor may be a hydromagnetic synchronous motor, but the invention is not limited thereto. Drag 2 = / 〇 includes matrix converter 20, turn-in command terminal 42, switch select group 311 influenza module 32, feedback circuit 33 and commutation logic

The above elements of the Hr person are electrically connected to each other. The matrix converter 20 has switches 7L to S33' therein, but the matrix converter 20 can be considered to include the virtual converter 21 and the virtual converter 22 in this embodiment. The virtual converter 21 converts the AC power to a DC power source, and the virtual converter 22 converts the DC power to AC power. The matrix converter 2A can be connected to the power supply terminal 41 to receive a wheel-in voltage VN. The power supply terminal 41 can be a power source external to the control system 10, such as a power outlet, but the invention is not limited thereto. The input command terminal 42 is used to input the current command i' to control the matrix converter 20. The input voltage VN is a three-phase AC voltage, and the current command "is also a three-phase alternating current. The matrix converter 20 can control the motor 90 according to the input voltage VN and the current command i'. The switching selection module 31 and the current sensing The module 32 can be disposed in the DSP chip 30. However, the present invention is not limited thereto. The switching selection module 31 and the current sensing module 32 are used to control the switching of the switching elements S11 to S33 in the matrix converter 20. The current sensing module 32 can control the virtual converter 22 via the feedback circuit 33. The method of controlling the same will be described later in detail. The commutation logic circuit 51 is used to protect the switching elements S11 to S33 of the matrix converter 20. In order to avoid component damage caused by the fast switching of the matrix converter 20. The commutation logic circuit 51 can be a CPLD chip or an FPGA chip, but the invention is not limited thereto. Since the control system 200919939 is in the present embodiment, the power input is voltage. In the form, and the output load is an inductive load, the switching mode of the matrix converter 20 of the embodiment has the characteristics that the switch on the input side must not be short-circuited and the output side switch must not be opened. However, the control system 10 of the present invention is not limited to the limitation of this embodiment. Next, please refer to FIG. 4 for an architectural diagram of the matrix converter of the present invention. In order to facilitate analysis and calculation, the switching element S11 in the matrix converter 20 ~S33 can be represented by a virtual converter 21 and a virtual converter 22. The virtual converter 21 includes virtual switching elements cl-c6, and the virtual converter 22 includes virtual switching elements q 1 -q6. Input and output of the virtual converter The relationship between them is expressed as follows:

Van c3 'VAN ' Vbn cl c5 = q3 q6 c4 c6 cl VBN Vcn q5 q2 VCN _ where VAN, VBN, VCN are the input voltages, and Van, Vbn, Vcn are the output voltages. The relationship between the output of the matrix converter 20 can be expressed as:

Van '511 512 513 ' 'VAN Vbn ~ 521 S22 523 VBN Vcn 531 532 533 VCN Therefore, the switching function formula of the matrix converter 20 can be obtained by the following equation: '511 512 513' cl c3 c5 521 S22 523 ~ q3 q6 531 C4 c6 c2 S23 S33 q5 q2 Since the switching function of the matrix converter 20 has been widely used in the technology of 200919939, it will not be repeated here. Next, please refer to FIG. 5 for a flow chart of the steps of the switching method of the present invention. It should be noted here that although the control system 10 is taken as an example to describe the switching method of the present invention, the switching method of the present invention is not limited to the use of the control system 10. First, step 501 is performed: receiving an input voltage and current command. The matrix converter 20 receives an input voltage VN via the power supply terminal 41 and receives a current command i' from the input command terminal 42. The input voltage 1 VN is an AC input voltage VAN, VBN, VCN having three phases, and the current command i' is an alternating current ia', ib', ic' having three phases. Go to step 502: Determine the required DC link voltage value. In the present invention, the matrix converter 20 determines the DC link voltage Vdc in accordance with the rotational speed or current modulation method of the motor 90. In this embodiment, the DC link voltage is determined by the rotational speed of the motor 90. Since the back electromotive force of the motor 90 is proportional to the rotational speed, the back electromotive voltage is low at medium and low speed operation. The Q can be driven by the input power source without using a high voltage, so the control system 10 can distinguish the magnitude of the input DC link voltage Vdc by the rotational speed of the motor 90. However, since the rated speeds of the different motors 90 are not uniform, the magnitude of the input DC link voltage Vdc cannot be distinguished by the fixed rotational speed value. Therefore, in this embodiment, the rated rotational speed of the motor 90 can be utilized to divide the speed into several levels, thereby pairing with the input voltage. For example, it can be set to be more than five-fifths of the rated speed of the motor 90 as the input high voltage VHdc, and between the three-thirds to two-fifths of the rated speed is the input medium voltage VMdc, and the rated speed is less than one-fifth of the input low voltage. In the VSdc and the like, this embodiment divides the speed into 200919939 into three sections of high, medium and low, but the invention is not limited thereto. In another embodiment of the invention, current modulation is employed to determine the DC link voltage value Vdc. The current modulation method detects the direction and magnitude of the current to determine the adjustment switching order to modulate the output current. The matrix converter 20 can adjust the magnitude of the input DC link voltage Vdc using the error value of the motor 90 output current. The wheel current i is fed back to the current sensing module 32 via the feedback circuit 33, and the current error value is obtained by subtracting the current sensing output current i from the current command i'. If the error value of the actual output current i and the current life ''i' is larger, in order to make the value of the output current i of the motor 90 close to the value of the current command i', the input DC link voltage Vdc needs to be increased to generate a larger current. The slope is used to increase the current closed loop response. On the other hand, if the error value of the actual output current i and the current command i' is small, it means that the value of the output current i of the motor 90 is close to the value of the current command i'. Therefore, a high input voltage is not required, and the input DC link voltage Vdc can be reduced at this time. As a result, the current harmonics of the motor 90 at low rotational speeds can be reduced. Since the rated current of the motor 90 is different, the magnitude of the output current error value varies. In this embodiment, the output current error value can be set to be less than one-quarter of the rated current as the input low voltage, one-quarter to one-half is the input medium voltage, and more than one-half is the input high voltage. It should be noted that the present invention is not limited to the above-mentioned classification. Then, step 503 is performed: determining a virtual switch switching mode in the virtual converter. Please refer to FIG. 6 for the architecture diagram of the virtual converter of the present invention and FIG. 7 for the virtual DC link voltage of the matrix converter output of the present invention. 200919939

The virtual converter 21 is composed of six virtual switching elements cl-c6 in Fig. 6, the main purpose of which is to rectify the input voltages VAN, VBN, VCN into a DC link voltage Vdc to supply the voltage required by the virtual converter 22. The switching of this part of the virtual switching element cl-c6 is in accordance with the Kirchhoff current law, and the following basic restrictions must be met, namely cl+c3+c5=l and c2+c4+c6=l where state '(V denotes switching element) Cutoff, the state value of 'Γ indicates that the switching element is turned on. In the prior art, the matrix converter 20 takes the maximum voltage value of the input power source as the virtual DC link voltage, and is divided into six virtual switching elements cl-c6 according to different intervals. The required DC link voltage value Vdc is modulated. However, as can be seen from Fig. 7, the DC link voltage Vdc of the output can have three different variations due to the waveforms of the input voltages VAN, VBN, and VCN (Fig. 2A). The voltage Vdc can be divided into a high voltage VHdc, a medium voltage VMdc, and a low voltage VSdc, wherein the high voltage VHdc is a DC voltage value in the prior art. The high voltage VHdc varies between 0.866Vpk and lVpk, and the average voltage is 0.955 Vpk. The medium voltage VMdc varies from 0.5 Vpk to 0.866 Vpk, and the average voltage is 0.699 Vpk. The low voltage VSdc varies between 0 and 0.5 Vpk, and the average voltage is 0.256 Vpk. The mathematical formulas of these three voltages can be expressed as follows: : high Pressure VHdc: < ω5ί < π / 6 K-cic (0 = vPk c〇s (200,919,939 iys〇 voltage VMdc U) two low-voltage VSdc Κ-ΑΟ = ·

Vpkcos^/3 + ast) νρ^〇8(π/3-ωχί)

Vpkcos^/3-ast) Vpkcos{Kl3 + mst) -π 16< ωχί < 0 0 < ω/ <π/6 -π 16< ω8ί < 0 0 < ω3ί <π/6 where υο The high voltage instantaneous value of the DC link is the instantaneous value of the voltage in the DC link, which is the low voltage instantaneous value of the DC link, and the peak value of the input voltage. In order to select the switching pattern of the virtual switching elements c 1 -c6, in the present embodiment, the input voltage VN is periodically divided into 12 sections I to XII, and any of the three types of DC link voltage values can be selected. The matrix converter 20 can cause the virtual converter 21 to output three different voltage values by controlling the virtual switching element cl-c6. The switching patterns of the last intervals I to XII and the three voltage values are shown in Figs. 8A-8C. 8A is a schematic diagram of a switching pattern of a high voltage, FIG. 8B is a schematic diagram of a switching pattern of a medium voltage, and FIG. 8C is a schematic diagram of a switching pattern of a low voltage. On the other hand, the matrix converter 20 can determine the time of the high-, medium-, and low-voltage switching patterns of each cycle according to the magnitude of the DC link voltage value Vdc required by the motor 90 in different periods. For example, section I to section IV can be set to 200919939. Oxygen pressure VHdc' section v to section xh is the medium voltage VMdc. Therefore, compared with the ribs, the present method has more degrees of freedom for the adjustment of the DC (four) s. Then proceed to step 5〇4: Determine the virtual switch in the virtual converter. FIG. 9 is a structural diagram of a virtual converter according to the present invention. In the virtual variable flow stomach 22 part is driven by six virtual switching elements W♦ whose main role is to utilize the convergence of the six virtual switching elements ql-q6, 9G three-phase output currents ia, ib, ie can effectively follow Current. (10) Γ, lc'' and then the torque of the motor 90 is controlled to achieve various operational functions such as starting and steering. The basic limitation of the virtual converter U 1 switching pattern is: ql+q4=l , q3+q6=l and q5+q2=1 conduction ^ ^ method is to determine the switching circuit of the switching element according to the f-stream modulation method 33 π / Γ output side phase arm & for example 'output current ^ via feedback = ^ feedback to the current sense touch 32, by the current command ia ^ ^,, output pack muscle la, the current error The value △ is that the conduction or wear of the quasi-switching elements ql and q4 is positive, indicating that the actual current ia is lower than the reference power ia, and should be made by the virtual switching element ql. This arm a acquires f^ Λ ^ so that the output side phase takes the current. If ^ is a negative value', it is expressed in the reference current ia. At this time, the current of the phase arm a of the output side should be reduced by the switch element q11 and the same. Similarly, the conduction or wear of the output side phase / 'and is determined by -a, %, and the virtual switch is 200919939. 5 and the material pass or cutoff, then 仏 (= flow error value and virtual open _ change 1 is the three-phase wheel power outage of the present invention, the state is Ί, the map. The state value is Ό ' indicates the next step 5〇5: Switching mode of the switch element of the shirt. Through the above-mentioned step 503, the switching element of the fish is...6:===the parameter of the switching function of the switch 2. That is, the figure η,: the matrix converter of the month actually switches Corresponding diagram, table, to =================================================================================================== The internal damage is destroyed. Please refer to the matrix converter of the present invention in Figure A-12C: Intention. Figure 12 is a three-step change of the matrix converter of the present invention. The J-phase of the phase method: Shi == Order: The matrix converter of the invention of the second St performs three; the phase diagram of the commutation ^ consistent application mode. ~ Le 200919939 For the matrix converter 20, one phase on the output side (eg: Phase a) will be connected to the power input side phase arms A, B and C by three bidirectional AC switches. The principle that the short circuit and the output side switch must not be opened is closed, and only one switch of one phase of the output side is in the on state at this time point. Therefore, when the switching element is switched, the original conduction switch must be gradually adjusted according to the flow of current. Transfer to another set of switches to avoid burnout of the switch. This commutation mode is a three-step commutation method. In Figures 12A-12B, the switching element S11 is switched to the switching element S12 as an example. For example, the switching element S11 includes two insulated gate bipolar transistors (IGBTs) mAal and mAaO, and the switching element S12 includes two insulated gate bipolar transistors mBal and mBaO. It is assumed that the load current is large enough. In this case, the current output current ia of the output side phase arm a flows from the power input side to the load output side. Before the switching of the two switching elements S11 and S12, the excitation signal is simultaneously sent to the two of the switching elements SI1. Insulated gate bipolar transistor mAal and mAaO. However, due to the flow direction of the output current ia, only the IGBT #t bipolar transistor mAal is actually turned on. The power supply of the input side phase arm A is switched to the power supply of the input side phase arm B. At this time, the insulated gate bipolar transistor mMaO should be turned off first, and after a delay time AT, the insulated gate bipolar transistor mBal is turned on. To avoid short circuit on the input side of the power supply or open on the output side of the load. When the output current ia is gradually transferred from the input side phase arm A to the input side phase arm B, the IGBT of the IGBT is turned off. After a delay time of AT Then, the insulated gate bipolar transistor mBaO is turned on to complete the entire commutation procedure. If the load current is reversed from the load side to the power supply side, the cutoff timing of the insulated gate bipolar transistor mAal and mAaO should be before 200919939. The conduction 昉 of the δ week' and the insulated gate bipolar transistors mBa 1 and mBa〇 are reversed. $ μ In addition, if the output current ia is too small to clearly determine the flow direction, in order to avoid the current flow direction error, the insulated gate bipolar 'electrical crystal ^ burning treasure, and the commutation mode should be adjusted accordingly. The timing diagram is shown in Figure pc. The switching element S11 is switched to the switching element S12 as an example. Before the two switching elements SU and the switching element S12 are switched, the excitation signal is simultaneously sent to

Insulated gate bipolar transistor mAal and mAa〇. First, the input side phase arm A is switched to the power source of the input side phase f B . At this time, the insulation: the dual crystal maa0 and mAal are cut off. After a delay time, the insulated gate bipolar transistor mBal and the shirt == are not turned on, so that the energy storage of the inductive load is not released. This increases the energy storage of the inductive load. "The road (not shown) absorbs the safe commutation circuit of the illustrated convertible device 20. The inter-logic logic circuit 51 that performs the commutation timing by the two-array converter protects a group of switching elements', thus commutating SH : 2 in / there are 9 sets of logic 511 to protect the switching element drive signal, the nine switches of the matrix converter 20 su~s33 excitation circuit and then the Qiuke bus to the commutation logic circuit 5 swapping logic 511 18 豕珊双极电晶., v, can get different DC link electric dust value. He drives the motor 9〇 in 200919939. It should be noted here that the switching method of the present invention is not in the order of the above steps. However, as long as the object of the present invention can be achieved, the above steps can be changed. Next, please refer to FIGS. 14A-14C for the DC link power I of the matrix conversion crying of the present invention. FIG. 14A is a high power (four) The 14B° is the medium voltage region and the HC is the low voltage region. The matrix converter of the present invention can utilize the three different high, medium and low virtual powers as the input power source, and the output current is good. (4) Wave size, and advance - improve the pulse of the motor 9q Torque Ripple Fig. 15A to Fig. 18 The actual measured waveform diagram lift Μ15A is the measured waveform of the output phase a current using the prior art. (4) Matrix converter 2〇 output a phase current Measured waveform. Slightly = Ray, "^° The current harmonics obtained by the present invention are significantly improved over the prior art switching strategy. Figure 16 is a transient response g of the speed transient response waveform L of the present invention when the two rated speeds are 2000 rpm. ^ L,, *, ,, 〇.9 seconds. Fig. 17 shows the speed response of the motor of the present invention. When the speed is changed to the steady state, the instantaneous addition of 5 Newtons to the return of J 5 is reduced by about 15 rpm, and recovered within 0.5 seconds. This control system of the present invention enables the motor (10) to have. Figure 18 is a diagram showing the rotation speed command of the present invention as cycle ==. At this time, the speed command is not required to improve the switching speed of the power component, which is a reduction in current harmonics and pulsating torque of the 200920099 90. The speed control performance of the motor 90 at medium and low speeds is greatly improved. To sum up, the present invention, regardless of its purpose, means and efficacy, shows its distinctive features of the prior art. You are requested to review the examinations and grant the patents as soon as possible. It is to be noted that the various embodiments described above are intended to be illustrative only, and the scope of the invention is intended to be limited by the scope of the appended claims. [Description between the drawings] Figure 1 is the actual architecture of the matrix converter. 2A is a schematic diagram of a three-phase input voltage. 2B is a schematic diagram of a prior art virtual DC link voltage. Figure 3 is a block diagram of the control system of the present invention. 4 is a virtual architecture diagram of a matrix converter of the present invention. Figure 5 is a flow chart showing the steps of the switching method of the present invention. Figure 6 is a block diagram of a virtual converter of the present invention. Figure 7 is a schematic diagram of the virtual DC link voltage of the matrix converter output of the present invention. 8A-8C are diagrams showing the switching patterns of the respective sections of the present invention and the two kinds of voltage values. Figure 9 is a structural diagram of a virtual converter of the present invention. Figure 10 is a schematic illustration of the three-phase output current error value and switch switching pattern of the present invention. 11 is a schematic diagram of a correspondence table of actual switching of the matrix converter of the present invention. 200919939 Fig. 12A is a diagram showing the structure of a switching element of the present invention. 12B-12C are timing diagrams of a three-step commutation method of the matrix converter of the present invention. Figure 13 is a logic gate circuit in which the matrix converter of the present invention performs a commutation timing. 14A-14C are graphs of DC link voltage measurements on a matrix converter of the present invention. 15A-15B are measured waveforms of the output current of the matrix converter. Figure 16 is a waveform diagram of the velocity transient response of the present invention. Figure 17 is a graph showing the motor speed response of the present invention. Fig. 18 is a view showing the measurement of the motor speed tracking response in which the rotational speed command is a periodic triangular wave. [Main component symbol description] Control system 10 Matrix converter 20 Virtual converter 21 Virtual converter 22 DSP chip 30 Switching selection module 31 Current sensing module 32 Feedback circuit 33 Power supply terminal 41 Input command terminal 42 200919939 Change Phase logic circuit 51 logic gate 511 motor 90 output current i, ia, ib, ic current command i', ia', ib', ic'

Current error value △ ia, △ ib, △ ic Input voltage VN DC link voltage Vdc High voltage VHdc Medium voltage VMdc Low voltage VSdc Switching element S11~S33 Virtual switching element cl-c6, ql-q6 Interval I~XII Output side phase arm a, b, c ◎ input side phase arm A, B, C insulated gate bipolar transistor maaO, mAal, mBaO, mBal

Claims (1)

200919939 Patent application scope control system is used to: control motor, the control system includes a matrix converter, has a number of 4 mountain logic switch 'the matrix converter can be - from the power supply terminal to receive - input voltage An input command terminal for inputting a current command: a selection module for controlling the matrix converter 2: a logic switch; and a current sensing module for sensing the matrix converter - The output current ' is compared with the current command to obtain a money error value, wherein = matrix conversion (4) uses the (4) selection module and the current sensing mode, and switches to a different virtual DC voltage value to drive the motor. 2. If you apply for a patent range! The control system of the present invention further includes a commutation logic circuit for determining the turn-on and turn-off sequence of the logic switch of the complex number, wherein the commutation logic is in which the commutation logic is 3. As described in claim 2 The control system circuit can include nine sets of logic gates. 4. The control system circuit as described in claim 3 can be a CPLD chip or an FPGA chip. The circuit of the control system as described in claim 4, further comprising a buffer circuit. The control system of claim 1, wherein the matrix converter can include a virtual converter. With a virtual converter, the complex logic 22 200919939 can be multiplied by the function of the virtual switch of the virtual converter and the virtual switch of the virtual converter. 7. The control system of claim 1 (4), further comprising a feedback circuit, wherein the current sense group further comprises a circuit via (4) (10) to obtain the current error value. 8. The control system of claim i, wherein the switching selection module and the current sensing module are disposed in a Dsp wafer. 9. The control system of claim i, wherein the different virtual DC voltage values may comprise a high DC value, a virtual DC voltage of a medium voltage voltage value.八^1〇.= The control system of claim 1, wherein the wheel-in voltage is a three-phase AC voltage, and the wheel current and the current command three-phase alternating current. 11. A switching method for a value, the method comprising: a matrix converter to switch the wheel-out voltage Receiving an input voltage and a current command; determining a desired DC link voltage value; switching the matrix converter DC voltage value; and a plurality of logic switches to obtain the virtual control using the virtual DC voltage value - the motor. 12. The switching method of claim 5, wherein the step of determining the DC link voltage value comprises using a small value of the motor speed to determine the virtual DC voltage value to be obtained. 23 200919939 13. The step of switching the DC link power value as described in the scope of claim 5 includes using the size of the - wheel power to determine (4) the desired DC value 14 = please refer to the patent item u The logic of switching the complex logic in the array converter includes switching the virtual switch in a virtual converter; and switching the virtual switch in a virtual converter. 15. The switching method of claim 14, wherein the step of virtual switching within the device comprises the step of using a current modulation = to determine a switching mode. "丨<*°周衣法16·如=Please refer to the switching method described in item n of the patent range, the straight: Α voltage step further includes obtaining - high voltage value: virtual value of a voltage value or a low voltage value DC voltage. The dry % π switching method as described in claim m = the step of pressing and the current command further comprises receiving a voltage and receiving a three-phase alternating current. For example, u 18. The multi-step commutation method is switched in a plurality of logic switches in the switching matrix converter described in the U.S. patent application. The steps of the pain switch include the execution - three 24