JP4135026B2 - Power converter and control method of power converter - Google Patents

Description

  The present invention relates to a power converter and a method for controlling the power converter.

  As a typical circuit configuration of an inverter, an indirect AC power conversion circuit that converts commercial AC to DC via a rectifier circuit and a smoothing circuit and outputs desired AC by a voltage source converter is generally used. On the other hand, as a method of directly obtaining an AC output from an AC voltage, a direct power converter represented by a matrix converter is known, and a large capacitor and a reactor for smoothing voltage pulsation due to a commercial frequency are unnecessary. The conversion device can be expected to be miniaturized, and has recently been attracting attention as a next-generation power conversion device.

  A conventional direct power converter includes a PWM rectifier that converts a three-phase AC voltage into a DC voltage, and a PWM inverter that converts the DC voltage converted by the PWM rectifier into a predetermined three-phase AC output voltage. There is a thing (for example, refer to JP, 2004-266972, A (patent documents 1)).

  This direct power converter generates a trapezoidal wave command signal based on an input current command, compares the trapezoidal wave command signal with a carrier signal, and generates a PWM modulation signal that turns on and off the switching circuit of the PWM rectifier. Yes. Also, a PWM modulation signal for turning on / off the switching circuit of the PWM inverter is generated by comparing a triangular wave obtained by modifying the carrier signal with an output voltage command.

  However, since the direct power converter generates the trapezoidal wave command signal by calculation based on the input current command, there is a problem that the calculation load of the control unit increases.

In the direct power converter, the carrier waveform on the PWM inverter side needs to be deformed, so that the modulation waveform generation is complicated and the control circuit is complicated. Further, when a carrier generation circuit for supplying a carrier signal is separately used for the PWM rectifier and the PWM inverter, there is a problem that the circuit of the control unit becomes complicated.
JP 2004-266972 A

  Accordingly, an object of the present invention is to provide a power conversion device and a method for controlling the power conversion device that can reduce the calculation load of the control unit with a simple configuration.

  Another object of the present invention is to provide a power conversion device and a method for controlling the power conversion device that can simplify the circuit of the control unit.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
で表される所定の式を用いて生成するか、または、上記所定の式に基づいて予め設定されたテーブルを用いて生成することを特徴とする。
ここで、上記指令信号生成部により台形波状の指令信号を生成するときの上記基準信号は、変換部が三相交流入力電圧を直流電圧に変換する場合は、三相交流入力電圧のうちの基準となる信号を用い、変換部が直流電圧を三相交流出力電圧に変換する場合は、例えば上記三相交流出力電圧を作るための基準となる信号を用いる。 To solve the above problems, the power conversion device of this invention,
A converter unit that converts a three-phase AC input voltage into a DC voltage; and an inverter unit that converts the DC voltage converted by the converter unit into a predetermined three-phase AC output voltage. The converter unit and the inverter unit A power converter that does not have a smoothing filter in the DC link part connecting
A command signal generator for a converter unit that generates a trapezoidal wave command signal for a converter unit based on a phase angle of a reference signal generated so as to be synchronized with the three-phase AC input voltage;
A carrier signal generator for generating a carrier signal;
An inverter command signal generator for generating an inverter command signal for outputting the predetermined three-phase AC output voltage;
The trapezoidal converter unit command signal from the converter unit command signal generation unit is a three-phase command signal expressed in phase voltage, and the two-phase command signal of the three-phase command signals is An intermediate phase detection unit for detecting a current flow ratio of an intermediate phase that is a command signal of another phase that switches when representing a conduction state;
The inverter unit based on the current ratio of the intermediate phase from the intermediate phase detection unit so that the inverter unit can perform pulse width modulation using the same carrier signal as that used in the converter unit. The amplitude of the inverter unit command signal from the command unit for generating the inverter is corrected, and two switching between the intermediate phase and the other two phases of the conduction state of the corrected inverter unit command signal An arithmetic unit that reverses the polarity of the other command signal represented by the conduction ratio by giving an offset to the one command signal represented by the conduction ratio with respect to the state ,
The converter unit is configured to perform the three-phase operation by a pulse width modulation method based on a comparison result between the trapezoidal converter unit command signal from the converter unit command signal generation unit and the carrier signal from the carrier signal generation unit. Convert AC input voltage to the above DC voltage,
The inverter unit converts the direct current converted by the converter unit by a pulse width modulation method based on a comparison result between the inverter command signal corrected by the arithmetic unit and the carrier signal from the carrier signal generation unit. The voltage is converted into the predetermined three-phase AC output voltage,
The converter unit command signal generation unit is configured to determine the slope region of the trapezoidal converter unit command signal.

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
Or a table set in advance based on the predetermined formula.
Here, the reference signal when generating the trapezoidal wave-shaped command signal by the command signal generation unit is the reference of the three-phase AC input voltage when the conversion unit converts the three-phase AC input voltage into the DC voltage. When the converter converts the DC voltage into a three-phase AC output voltage, for example, a signal serving as a reference for generating the three-phase AC output voltage is used.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
で表される所定の式を用いて生成するか、または、上記所定の式に基づいて予め設定されたテーブルを用いて生成することによって、複雑な演算により台形波状のコンバータ部用指令信号を形成する必要がなく、簡単な構成で制御部の演算負荷を低減できる。 According to the power conversion device having the above configuration, for the pulsating voltage (current) waveform of the DC voltage converted by the converter unit, the three-phase AC output voltage (current) is not distorted. By correcting the inverter unit command signal by the command signal correcting unit, the DC voltage converted by the converter unit is converted into a predetermined three-phase AC output voltage based on the corrected inverter unit command signal. Is possible. At this time, the command signal generation unit for the converter unit, the slope region of the trapezoidal converter command signal for the trapezoidal wave,

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
A trapezoidal wave-shaped command signal for the converter unit is formed by a complicated calculation by using a predetermined expression expressed by the above or by using a table preset based on the predetermined expression. There is no need to do this, and the calculation load of the control unit can be reduced with a simple configuration.

  In addition, the converter unit command signal generation unit generates a trapezoidal converter unit command signal using the predetermined formula, thereby reducing the computation load and reducing distortion in the three-phase AC output voltage (current). ) Can be obtained reliably.

Moreover, in the power converter of one embodiment,
The PWM modulation signal generation unit for converter unit that generates the PWM modulation signal for converter unit by comparing the command signal for converter unit from the command signal generation unit for converter unit and the carrier signal from the carrier signal generation unit When,
The inverter part PWM that generates the inverter part PWM modulation signal by comparing the inverter part command signal from the inverter part command signal generation part with the same carrier signal used in the converter part A modulation signal generator,
The converter unit converts the three-phase AC input voltage into the DC voltage based on the converter unit PWM modulation signal generated by the converter unit PWM modulation signal generation unit,
The inverter unit converts the DC voltage converted by the converter unit into the predetermined three-phase AC output voltage based on the PWM modulation signal for the inverter unit generated by the PWM modulation signal generation unit for the inverter unit. To do.

  According to the power conversion device of the above embodiment, the circuit of the control unit can be simplified by enabling PWM modulation with one carrier signal common to the converter unit and the inverter unit.

  In the power converter of one embodiment, the carrier signal is a triangular wave signal.

  According to the power conversion device of the above embodiment, a circuit for pulse width modulation can be simplified by using a triangular wave signal suitable for PWM modulation as a carrier signal.

  In the power converter of one embodiment, the carrier signal is a sawtooth signal.

  According to the power conversion device of the above embodiment, carrier generation and modulation processing can be simplified by using a sawtooth signal as a carrier signal.

Moreover, in the power converter of one embodiment,
The converter part
Three switching circuits in which each phase voltage of the three-phase AC input voltage is input to one end and the other end is connected to the first DC link unit,
Each phase voltage of the three-phase AC input voltage is respectively input to one end, and has three switching circuits each connected to the second DC link portion and the other end.
The inverter part is
Three switching circuits in which each output terminal of the predetermined three-phase AC output voltage is connected to one end, and the other end is connected to the first DC link unit;
Each output terminal of the predetermined three-phase AC output voltage is connected to one end, and three switching circuits are connected to the second DC link portion.

Moreover, in the power converter of one embodiment,
A matrix converter having a virtual converter unit corresponding to the converter unit, a virtual inverter unit corresponding to the inverter unit, and a virtual DC link unit corresponding to the DC link unit,
The virtual converter unit and the virtual inverter unit are
Three switching circuits in which the first phase voltage of the three-phase AC input voltage is respectively input to one end, and the other end is connected to each output terminal of the predetermined three-phase AC output voltage;
Three switching circuits in which the second phase voltage of the three-phase AC input voltage is respectively input to one end, and the other end is connected to each output terminal of the predetermined three-phase AC output voltage;
A third phase voltage of the three-phase AC input voltage is input to one end, and three switching circuits are connected to the output terminals of the predetermined three-phase AC output voltage.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
で表される所定の式を用いて生成するか、または、上記所定の式に基づいて予め設定されたテーブルを用いて生成することを特徴とする。 Further, the control method of the power conversion device of this invention,
A converter unit that converts a three-phase AC input voltage into a DC voltage; and an inverter unit that converts the DC voltage converted by the converter unit into a predetermined three-phase AC output voltage. The converter unit and the inverter unit A method of controlling a power converter that does not have a smoothing filter in a DC link unit connecting
Generating a trapezoidal converter unit command signal by the converter unit command signal generation unit based on the phase angle of the reference signal generated so as to be synchronized with the three-phase AC input voltage;
Generating a carrier signal by a carrier signal generator;
Generating an inverter unit command signal for outputting the predetermined three-phase AC output voltage by the inverter unit command signal generation unit;
The trapezoidal converter unit command signal from the converter unit command signal generation unit is a three-phase command signal represented by a phase voltage, and two of the three-phase command signals are in a conductive state. A step of detecting a current flow ratio of the intermediate phase, which is another one-phase command signal that is switched when expressed, by the intermediate phase detection unit;
Based on the current flow ratio of the intermediate phase from the intermediate phase detection unit, so as to enable pulse width modulation using the same carrier signal as that used in the converter unit in the inverter unit, The amplitude of the inverter unit command signal from the inverter unit command signal generation unit is corrected, and the intermediate phase of the corrected inverter unit command signal is between the other two phases of the conduction state. Inversion of the polarity of the other command signal represented by the conduction ratio by giving an offset to one command signal represented by the conduction ratio for the two switching states;
By the pulse width modulation method based on the comparison result of the trapezoidal converter command signal from the converter command signal generation unit and the carrier signal from the carrier signal generation unit, the converter unit performs the three-phase operation. Converting an AC input voltage into the DC voltage;
The direct current converted by the converter unit by the inverter unit by a pulse width modulation method based on a comparison result between the command signal for the inverter unit corrected by the arithmetic unit and the carrier signal from the carrier signal generation unit. Converting the voltage into the predetermined three-phase AC output voltage,
In the step of generating the trapezoidal wave-shaped converter unit command signal by the converter unit command signal generation unit, the slope region of the trapezoidal wave-shaped converter unit command signal is:

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
Or a table set in advance based on the predetermined formula.

  According to the method for controlling the power converter, the three-phase AC output voltage (current) is not distorted with respect to the pulsating voltage (current) waveform of the DC voltage converted by the converter unit. By correcting the inverter unit command signal by the command signal correcting unit, the DC voltage converted by the converter unit is converted into a predetermined three-phase AC output voltage based on the corrected inverter unit command signal. It becomes possible. At this time, the converter unit command signal generation unit generates a slope region of the trapezoidal converter unit command signal by using a predetermined table or a predetermined formula, thereby performing a trapezoidal converter unit by a complicated calculation. It is not necessary to form a command signal for operation, and the calculation load on the control unit can be reduced with a simple configuration.

  In addition, the converter unit command signal generation unit generates a trapezoidal converter unit command signal using the predetermined formula, thereby reducing the computation load and reducing distortion in the three-phase AC output voltage (current). ) Can be obtained reliably.

  As is clear from the above, according to the power conversion device and the method for controlling the power conversion device of the present invention, the slope region of the trapezoidal wave-shaped command signal used for the PWM modulation of the converter unit or the inverter unit is set to a predetermined table or a predetermined level. By generating using the formula, the calculation load of the control unit can be reduced with a simple configuration.

  Before describing the illustrated embodiment of the power conversion device and the power conversion device control method of the present invention, the features of the power conversion device and the power conversion device control method of the present invention will be described.

  First, in a power conversion device that performs DC / AC conversion, a sine wave voltage waveform is also sinusoidal in the same manner as a phase voltage waveform generation method that obtains a sinusoidal line voltage with respect to a constant DC voltage. Derivation of the phase voltage signal wave from which the wave output is obtained will be described.

  Technical reference 1 (Lixiang. Wei, Thomas. A. Lipo), “A Novel Matrix Converter Topology with Simple Commutation. ) '', I Triple E (IEEE IAS2001), vol.3, pp.1749-1754.2001), the direct conversion circuit with DC link is a current source converter, so the current ratio of the line current is trapezoidal Is controlling. In this specification, the voltage type is considered, and the duality of the current type and voltage type (line current: line voltage, phase current: corresponding to phase voltage) is considered, and the line voltage is trapezoidal. Shall be controlled.

This technical document 1 relates to a modulation system of a direct conversion circuit with a DC link that does not have a smoothing or rectifying circuit in the DC link unit. As shown in FIG. 3, the direct conversion circuit with a DC link of this technical document 1 includes six switching circuits S _ap , S _bp , S _cp , S _an , S _bn , S _cn constituting a three-phase bridge circuit. A converter unit and an inverter unit composed of six switching circuits S _up , S _vp , S _wp , S _un , S _vn , S _wn constituting a three-phase bridge circuit are provided. The converter unit converts the three-phase AC input voltages V _a , V _b , and V _c from the three-phase AC power sources V _sa , V _sb , and V _sc into direct current. The inverter unit converts the DC voltage V _dc converted by the converter unit into a three-phase AC output voltage V _su , V _sv , V _sw .

4 (a) to 4 (d) show the waveforms of the respective parts based on the control principle of the direct conversion circuit with a DC link in the above-mentioned technical document 1. FIG. As shown in FIG. 4 (a), the phase voltage corresponds to one of two states of [two phase: positive, one phase: negative] and [two phase: negative, one phase: positive]. It can be divided into six regions every 60 degrees. Here, Region 1 and Region 2 based on the c phase will be described. Here, in region 1, the c phase that is the minimum phase is made conductive by the switching circuit S _cn, and the following current ratio d is used by using the switching circuits S _ap and S _bp for the a phase and the b phase that are the maximum or intermediate phase. Switching with _ac and d _bc . In likewise area 2, the c-phase is the maximum phase is made conductive by the switching circuit S _cp, an intermediate or a minimum phase a phase switching circuit b phase S _an,, the following flows ratio d using the S _bn Switching with _ac and d _bc .

  When the above operation is applied to six regions, the conduction ratio of each phase becomes a trapezoidal waveform as shown in FIG. Here, in order to show the switching state of the upper arm and the lower arm on the converter side, the upper arm is conducted when the conduction ratio is positive, and the lower arm is conducted when the conduction ratio is negative. .

で表され、ＤＣリンク電圧が脈流状の電圧波形となることが分かる。 At this time, as shown in FIG. 4 (c), the DC link voltage includes the line voltage Emax between the maximum phase and the minimum phase, and the intermediate phase between the minimum phase (region 1) and the maximum phase (region 2). It can be seen that two potentials of the line voltage Emid generated by the above are obtained. Also, by multiplying each DC link voltage by the current ratio, the average voltage V _dc is

It can be seen that the DC link voltage has a pulsating voltage waveform.

に基づき制御される。また、インバータの負荷は誘導性であるため電流源として捉えることができ、ＤＣリンク電流は通電時間が上式に示すように、脈流分ｃｏｓθ_inで振幅変調されているため、

で示されるように脈流状となる。ここで、上述のようにコンバータ側は一相が導通状態にあり、二相が各々の通流比ｄ_ac,ｄ_bcでスイッチングするため、領域１において入力電流は、

の関係となる。 On the other hand, on the inverter side, since voltage control is performed using the pulsating voltage V _dc , the energization time is multiplied by the pulsating current component cos θ _in so that the modulated wave compensates the pulsating current component,

It is controlled based on. Moreover, since the load of the inverter is inductive, it can be regarded as a current source, and the DC link current is amplitude-modulated by the pulsating current component cos θ _in as shown in the above equation.

As shown in FIG. Here, as described above, since one phase is in a conducting state on the converter side and two phases are switched at respective conduction ratios d _ac and d _bc , the input current in region 1 is

It becomes the relationship.

  As described above, since the waveform is obtained by multiplying the trapezoidal wave ratio and the pulsating current shown in FIG. 4B, the input current can be a sine wave shown in FIG.

  Further, as a line voltage control method for a constant DC voltage, a signal wave shown in Technical Document 2 (Japanese Patent Publication No. 6-081514) is known (right column, page 10, third column of Technical Document 2). (Refer to the description on the 25th line of the left column on page 4 and FIGS. 1 and 2).

で表される。この(１)式の相電圧指令信号Ｖ_u ^*,Ｖ_v ^*,Ｖ_w ^*に中間相電圧の１／２を加算することで、１相をπ／６遅れ、他の２相をπ／３進みの極性が相互に異なる相電圧指令信号Ｖ_u ^**,Ｖ_v ^**,Ｖ_w ^**は、

で表現される。上記技術文献２では、Ｖ_uv線間電圧の位相を基準に示しているが、ここでは、相電圧を基準とするため、相順を読み替えて表記している(WはU、UはV、VはW)。 Here, the phase voltage command signals V _u ^* , V _v ^* , V _w ^* are

It is represented by By adding 1/2 of the intermediate phase voltage to the phase voltage command signals V _u ^* , V _v ^* , V _w ^* of the equation (1), one phase is delayed by π / 6 and the other two phases are π / 3 Phase voltage command signals V _u ^** , V _v ^** , V _w ^** with mutually different polarities are

It is expressed by In the above-mentioned technical document 2, the phase of the V _uv line voltage is shown as a reference, but here, since the phase voltage is used as a reference, the phase order is replaced (W is U, U is V, V is W).

で表される。そして、位相角０〜π／３の領域では、線間電圧Ｖ_uwが最大値となるため、

の関係式が成り立つ。ここで、(４)式を(２)式に代入することにより、相電圧指令信号Ｖ_u ^**,Ｖ_v ^**,Ｖ_w ^**は、

で表される。 Moreover, since the pulsating voltage V _link is based on the voltage type, it is determined by the maximum value of the line voltage,

It is represented by And in the region of phase angle 0 to π / 3, the line voltage V _uw becomes the maximum value,

The following relational expression holds. Here, by substituting equation (4) into equation (2), the phase voltage command signals V _u ^** , V _v ^** , V _w ^**

It is represented by

When the command value is rewritten to a triangular wave carrier comparison base value of amplitude 1, the phase voltage command signals V _u ^** , V _v ^** , V _w ^** are expressed by the relationship between the carrier amplitude and the output voltage in the following equation (6): It can be rewritten as equation (8).

  The above results are the same as those obtained by dividing each phase command value by the maximum phase voltage in the line voltage control waveform shown in FIG. 5A. In the region where the phase angle is 0 to π / 3, the r phase is the maximum phase voltage. Become. FIG. 5B shows the result of the same calculation performed on six regions for each phase angle π / 3, and a trapezoidal wave modulation waveform (phase voltage) energized by 120 degrees.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
で表される所定の式を用いて生成するか、または、上記所定の式に基づいて予め設定されたテーブルを用いて生成することによって、簡単な構成で制御部の演算負荷を低減することができる。 Therefore, in the power conversion device and the method for controlling the power conversion device according to the present invention, the slope region of the trapezoidal wave-shaped command signal (the trapezoidal wave modulation waveform with 120-degree conduction) used for the PWM modulation of the converter unit or the inverter unit

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
The calculation load of the control unit can be reduced with a simple configuration by generating using a predetermined expression expressed by the above or using a table set in advance based on the predetermined expression it can.

  Next, it is shown that the trapezoidal wave modulation waveform obtained as described above is equivalent to the line current command shown in the technical document 1. In the current type, the line current corresponds to the line voltage in the voltage type, so the line current command signal in FIG. 4B is compared with the trapezoidal wave modulation waveform (line voltage) in FIG. 5C.

で示されるが、領域１における０〜π／３の位相角で表記すると、

に書き換えられる。 In FIG. 4B, the b-phase line current command signal d _bc is

Is represented by a phase angle of 0 to π / 3 in region 1,

To be rewritten.

で表すことができ、(１０)式と等しいものとすると、(１１)式より、

が成り立てば良い。この(１２)式の右辺を、加法定理を用いて変形すると、

が成立する。 Further, when the line voltage command of FIG. 5C and the line current command signal of FIG.

If it is equal to equation (10), from equation (11)

Should be established. When the right side of equation (12) is transformed using the addition theorem,

Is established.

  Accordingly, the line voltage command signal generated by the control method of the power conversion device of the present invention is equivalent to the line current command shown in the technical document 1, so that, for example, the technical document 3 (Takashita Takeshita, two other authors, “ Voltage-type and current-type duality shown in Triangular wave comparison type PWM control of current-type three-phase inverter / converter ", Electrotechnical D, Vol.116, No.1,1996) (See Table 1 of Technical Document 3) By applying a logical operation based on the above, it is possible to easily generate a current type PWM pattern from a voltage type.

  Although the method for generating the phase voltage command signal has been described above, the PWM modulation method can be applied to a space vector modulation method power converter using a voltage vector in addition to a method using a triangular wave carrier signal.

The upper side of FIG. 6A is a vector diagram showing a space vector in PWM modulation of the space vector modulation method and a diagram for explaining a voltage vector in FIG. 5A. As shown in the vector diagram, the voltage vector is a non-zero vector in six states (V _{1 to} V ₆ ) out of eight states, and the remaining two states (V ₀ , V ₇ ) are zero states.

で表される。この位相角０〜π／３における電圧指令信号Ｖ_r ^*,Ｖ_s ^*,Ｖ_t ^*は、

で表される。図６Ａの下側は、図５Ａの線間電圧制御波形に位相角０〜π／３に対応する電圧ベクトルを示している。なお、図６Ａでは電圧制御率ｋsを０.５としている。ここで、位相角φが０〜π／３において電圧指令信号Ｖ_s ^*,Ｖ_t ^*の中間相電圧Ｖ_s ^* _{_mid}は、

で表される。図６Ｂに示すように、図５Ｂの台形波変調波形(相電圧)に位相角０〜π／３に対応する電圧ベクトルを示している。そして、空間ベクトル変調方式の基本式のτ₄／Ｔ₀とτ₆／Ｔ₀は、

で表される。この基本式を、図６Ａ中の表で位相角π／３毎に読み替えて、電圧ベクトルの出力時間を決定することによって、ＰＷＭ波形生成を行うことができる。 In this space vector modulation system, when the voltage vector output time τ ₀ , τ ₄ , τ ₆ at a phase angle φ of 0 to π / 3 and the voltage control rate is ks, the basic expression of the voltage vector is

It is represented by The voltage command signals V _r ^* , V _s ^* and V _t ^{* at} this phase angle 0 to π / 3 are

It is represented by The lower side of FIG. 6A shows a voltage vector corresponding to the phase angle 0 to π / 3 in the line voltage control waveform of FIG. 5A. In FIG. 6A, the voltage control rate ks is set to 0.5. Here, when the phase angle φ is 0 to π / 3, the intermediate phase voltage V _s ^* _{_mid} of the voltage command signals V _s ^* and V _t ^* is

It is represented by As shown in FIG. 6B, a voltage vector corresponding to a phase angle of 0 to π / 3 is shown in the trapezoidal wave modulation waveform (phase voltage) of FIG. 5B. And τ ₄ / T ₀ and τ ₆ / T ₀ in the basic formula of the space vector modulation method are

It is represented by The basic equation is read at every phase angle π / 3 in the table in FIG. 6A to determine the output time of the voltage vector, whereby the PWM waveform can be generated.

で表される。 As shown in FIG. 6C, the line voltage command signal V _st ^*

It is represented by

FIG. 7 shows the synchronous PWM modulation method disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2004-266972) in comparison with the modulation method of Technical Document 1. In FIG. 7, t _s is the carrier period, I (rt) is the current command, I (st) is the current command, d _rt is Tsuryuhi, d _st is _{Tsuryuhi, I r, I s, I} t is an input Current, I _dc is a DC link current, V ₀ , V ₄ , V ₆ are voltage commands, d ₀ is a conduction ratio corresponding to the voltage command V ₀ , and d ₄ is a conduction ratio corresponding to the voltage command V _4. . V _u , V _v , and V _w are inverter gate signals.

  In FIG. 7, the carrier cycle on the converter side is divided into two switching states in which current is supplied to st and rt, and the current ratios of the inverters are different. Is used. Further, the signal wave to be compared with the carrier signal is corrected by the carrier amplitude by being multiplied by the current ratio of the converter. For this reason, the modulation circuit configuration is complicated as shown in Patent Document 1 (described in paragraphs [0021] to [0026] of FIG. 4 and FIG. 4).

On the other hand, FIG. 8 is a diagram showing a PWM modulation method using a triangular wave carrier signal of the power converter of the present invention. In FIG. 8, t _s is the carrier period, I (rt) is the current command, I (st) is the current command, d _rt is Tsuryuhi, d _st is _{Tsuryuhi, I r, I s, I} t is an input Current, I _dc is a DC link current, V ₀ , V ₄ , V ₆ are voltage commands, d ₀ is a conduction ratio corresponding to the voltage command V ₀ , and d ₄ is a conduction ratio corresponding to the voltage command V _4. . V _u , V _v and V _w are gate signals for the upper arm, and / V _u ′, / V _v ′ and / V _w ′ are gate signals for the lower arm.

  In FIG. 8, the same carrier signal is used for the converter side and the inverter side. Of the two command signals whose amplitudes are corrected as in the prior art, one command signal is offset and compared with the carrier signal. On the other hand, the polarity of the command signal is inverted and compared with the carrier signal, and the resulting gate signal is inverted. In addition, the gate signals in each period can be obtained as a gate signal having the same phase by taking a logical sum.

FIG. 9 is a diagram showing a PWM modulation method using a sawtooth carrier signal of the power converter of the present invention. In FIG. 9, t _s is the carrier period, I (rt) is the current command, I (st) is the current command, d _rt is the conduction ratio, d _st is the conduction ratio, and I _r , I _s , and I _t are input. Current, I _dc is a DC link current, V ₀ , V ₄ , V ₆ are voltage commands, d ₀ is a conduction ratio corresponding to the voltage command V ₀ , d ₄ is a conduction ratio corresponding to the voltage command V ₄ , d ₆ is a conduction ratio corresponding to the voltage command V ₆ . V _u , V _v and V _w are gate signals for the upper arm, and / V _u ′, / V _v ′ and / V _w ′ are gate signals for the lower arm.

The power conversion device shown in FIG. 9 can simplify carrier generation and modulation processing, and has a configuration more suitable for software. However, in the direct conversion circuit with a DC link shown in the technical document 1, in order to commutate the converter side in the zero vector period, it is necessary to use both V ₀ and V ₇ zero vectors. And it is disadvantageous in terms of loss. Further, as is generally known, the frequency of the sawtooth wave is f with respect to the triangular wave frequency 2f of the main component of the voltage spectrum by the carrier, and the noise side is also inferior.

  Thus, according to the power conversion device and the method for controlling the power conversion device of the present invention, the carrier comparison base that does not cause distortion in the line voltage (line current) with respect to the pulsating voltage (current) waveform. The phase voltage command waveform (or space vector modulation method) can reduce the calculation load when generating the command signal.

  Also, the modulation circuit can be simplified by enabling synchronous PWM modulation with a single carrier signal (such as a triangular wave or a sawtooth wave) common to the converter unit and the inverter unit.

  Hereinafter, the power converter of this invention and the control method of a power converter are demonstrated in detail by embodiment of illustration.

[First Embodiment]
FIG. 1 is a configuration diagram of a direct power converter with a DC link according to a first embodiment of the present invention. The direct power converter with a DC link of the first embodiment does not have a smoothing filter in the DC link unit that connects the converter unit and the inverter unit.

As shown in FIG. 1, the direct power converter includes a converter unit 1 composed of switches S _rp , S _rn , S _sp , S _sn , S _tp , _{St n} , and switches S _up , S _un , S _vp , The inverter unit 2 composed of S _vn , S _wp , S _wn , the switches S _rp , S _rn , S _sp , S _sn , S _tp , S _{tn of the} converter unit 1 and the switches S _up , S _un , And a control unit 3 that outputs a gate signal for _{turning on} and off S _vp , S _vn , S _wp , and S _wn . The switches S _rp , S _rn , S _sp , S _sn , S _tp , _{St n} and the switches S _up , S _un , S _vp , S _vn , S _wp , S _wn are each configured by combining a plurality of switching elements. Switching circuit.

The converter unit 1, a three-phase AC power supply enter the phase voltage v _r from (not shown) to one end of the one end and the switch S _rn of the switch S _rp, one end switch S of the phase voltage v _s of the switch S _sp enter at one end of the _sn, we have entered the phase voltage v _t at one end of the one end and the switch S _tn of the switch S _tp. The other _ends of the switches S _rp , S _sp , S _tp are connected to the first DC link portion L1, respectively, while the other _{ends of} the switches S _rn , S _sn , _{St n} are connected to the second DC link portion L2, respectively. Yes.

Further, the inverter section 2 connects the one ends and the switch S _un switches S _up to the output terminal of the phase voltage v _u of the three-phase AC output voltage, one end of the switch S _vp to the output terminal of the phase voltage v _v And one end of the switch S _vn are connected, and one end of the switch S _wp and one end of the switch S _wn are connected to the output terminal of the phase voltage v _w . The other _ends of the switches S _up , S _vp and S _wp are connected to the first DC link portion L1, respectively, while the other _ends of the switches S _un , S _vn and S _wn are connected to the second DC link portion L2, respectively. Yes.

Further, the control unit 3 generates trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* based on a power supply synchronization signal V _r as an example of a reference signal for synchronizing with a three-phase AC input voltage. A trapezoidal wave voltage command generation unit 11 as an example of a command signal generation unit and a converter unit command signal generation unit, and a trapezoidal wave voltage command signal V _r ^* , V _s ^* , from the trapezoidal wave voltage command generation unit 11, A comparison unit 12 for comparing V _t ^* and the carrier signal, a current source gate logic conversion unit 13 that outputs a gate signal based on the comparison result from the comparison unit 12, and the trapezoidal wave voltage command generation unit 11 Based on the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^{* from} the intermediate phase detector 14 for detecting the _conduction ratios d _rt , d _st , and the carrier signal generator for generating the carrier signal 15 and an output voltage indicator for the inverter 2 An output voltage command signal generator 21 as an example of an inverter command signal generator that generates the command signals V _u ^* , V _v ^* , V _w ^* , and an output voltage command signal from the output voltage command signal generator 21 Based on V _u ^* , V _v ^* , V _w ^* and the flow ratios d _rt , d _st from the intermediate phase detector 14,
d _rt + d _st V ^* (V ^* : voltage vector of each phase)
On the basis of the output voltage command signals V _u ^* , V _v ^* , V _w ^* from the output voltage command signal generation unit 21 and the _conduction ratio d _rt from the intermediate phase detection unit 14,
d _rt (1−V ^* ) (V ^* : voltage vector of each phase)
, A comparison unit 24 for comparing the calculation results from the calculation units 22 and 23 and the carrier signal, and a logical sum for outputting a gate signal based on the comparison result from the comparison unit 24 And an arithmetic unit 25.

Converter section 1 of the switch S _rp by the gate signal from the current-source gate logic converting section _{13, S rn, S sp,} S sn, S tp, with on-off control of the S _tn, the gate signal from the OR operation unit 25 Thus, the switches S _up , S _un , S _vp , S _vn , S _wp , and S _wn of the inverter unit 2 are turned on / off.

  The intermediate phase detection unit 14 and the calculation units 22 and 23 constitute a command signal correction unit. Further, the comparison unit 12 and the current source gate logic conversion unit 13 constitute a converter PWM modulation signal generation unit, and the comparison unit 24 and the OR operation unit 25 constitute an inverter PWM modulation signal generation unit. .

で表される相電圧指令信号Ｖ_u ^***,Ｖ_v ^***,Ｖ_w ^***と同様に、台形波状電圧指令信号Ｖ_r ^*,Ｖ_s ^*,Ｖ_t ^*の傾斜領域における値を予めテーブルとして設定しておく。ここで、位相角φは、三相交流入力電圧の相電圧ｖ_rに同期している。 The trapezoidal wave voltage command generation unit 11 generates a slope region of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* using a predetermined table. Here, the equation (8) described in FIGS. 5A to 5C, that is,

In the same way as the phase voltage command signals V _u ^*** , V _v ^*** , V _w ^*** represented by the values in the slope region of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* Are set in advance as a table. Here, the phase angle φ is synchronized with the phase voltage v _r of the three-phase AC input voltage.

Note that the slope regions of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , and V _t ^* may be obtained using equations instead of the table.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
の所定の式を用いて、台形波状電圧指令信号Ｖ_r ^*,Ｖ_s ^*,Ｖ_t ^*の傾斜領域を夫々求める。これにより、演算負荷を低減しつつ、歪のない三相交流出力電圧(電流)を確実に得ることができる。 That is,

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
The slope regions of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , and V _t ^* are obtained using the predetermined formulas (1). Thereby, it is possible to reliably obtain a three-phase AC output voltage (current) without distortion while reducing the calculation load.

According to the direct power converter with a DC link configured as described above, the three-phase AC output voltage (current) is distorted with respect to the pulsating voltage (current) waveform of the DC voltage converted by the converter unit 1. The output voltage command signal is corrected by the command signal correction unit (14, 22, 23) so that the DC voltage converted by the converter unit 1 is converted into a predetermined three voltage based on the corrected output voltage command signal. Convert to phase AC output voltage. At this time, the trapezoidal wave voltage command generation unit 11 generates the slope regions of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* by using a predetermined table (or a predetermined expression), The calculation load on the control unit can be reduced with a simple configuration.

  By enabling PWM modulation with one carrier signal common to the converter unit 1 and the inverter unit 2, the circuit of the control unit can be simplified.

[Second Embodiment]
FIG. 2 is a configuration diagram of a matrix converter as an example of a direct power converter according to a second embodiment of the present invention.

As shown in FIG. 2, the matrix converter includes a conversion unit 4 including switches S _ur , S _us , S _ut , S _vr , S _vs , S _vt , S _wr , S _ws , S _wt and the conversion unit 4. switches _{S ur, S us, S ut} , S vr, S vs, S vt, S wr, S ws, and a control unit 5 that outputs a gate signal for turning on and off the S _wt. The conversion unit 4 corresponds to a virtual converter unit and a virtual inverter unit, and does not have a smoothing filter in a virtual DC link unit that connects the virtual converter unit and the virtual inverter unit. The switches S _ur , S _us , S _ut , S _vr , S _vs , S _vt , S _wr , S _ws , and S _wt are switching circuits configured by combining a plurality of switching elements.

The conversion unit 4, the phase voltage v _r of the switch S _ur of the three-phase AC input voltage from the three-phase AC power supply 6, S _vr, enter into one end of the s S _wr respectively, of the three-phase AC input voltage The phase voltage v _s is input to one end of each of S _us , S _vs , and S _ws , and the phase voltage v _t of the three-phase AC input voltage is input to one end of each of S _ut , S _vt , and S _wt . The other _ends of the switches S _ur , S _us , S _ut are connected to the output terminal of the phase voltage v _u , respectively, while the other _{ends of} the switches S _vr , S _vs , S _vt are connected to the output terminal of the phase voltage v _r , respectively. The other _{ends of the} switches S _wr , S _ws , and S _wt are connected to the output terminal of the phase voltage v _w , respectively.

Further, the control unit 5 outputs trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* based on a power supply synchronization signal V _r as an example of a reference signal for synchronizing with a three-phase AC input voltage. A trapezoidal wave voltage command generation unit 31 as an example of a command signal generation unit and a converter unit command signal generation unit, and a trapezoidal wave voltage command signal V _r ^* , V _s ^* , from the trapezoidal wave voltage command generation unit 31. A comparison unit 32 for comparing V _t ^* and the carrier signal, a current source gate logic conversion unit 33 that outputs a gate signal based on the comparison result from the comparison unit 32, and the trapezoidal wave voltage command generation unit 31 Based on trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^{* from} the intermediate phase detector 34 for detecting the _conduction ratios d _rt , d _st , and the carrier signal generator for generating the carrier signal 35 and an output voltage command signal for the converter 4 An output voltage command signal generation unit 41 as an example of an inverter command signal generation unit that generates V _u ^* , V _v ^* , and V _w ^*, and an output voltage command signal V _u from the output voltage command signal generation unit 41 ^{Based on *} , V _v ^* , V _w ^* and the flow ratios d _rt , d _st from the intermediate phase detector 34,
d _rt + d _st V ^* (V ^* : voltage vector of each phase)
On the basis of the output voltage command signals V _u ^* , V _v ^* , V _w ^* from the output voltage command signal generation unit 41 and the _conduction ratio d _rt from the intermediate phase detection unit 34,
d _rt (1−V ^* ) (V ^* : voltage vector of each phase)
, A comparison unit 44 for comparing the calculation results from the calculation units 42 and 43 with the carrier signal, and a logical sum for outputting a gate signal based on the comparison result from the comparison unit 44 An arithmetic unit 45 and a gate signal synthesis unit 50 that synthesizes the gate signals based on the signal from the current source gate logic conversion unit 33 and the signal from the logical sum calculation unit 45 are provided.

The switches S _ur , S _us , S _ut , S _vr , S _vs , S _vt , S _wr , S _ws , and S _wt of the conversion unit 4 are on / off controlled by the gate signal from the gate signal synthesis unit 50.

  The intermediate phase detection unit 34 and the calculation units 42 and 43 constitute a command signal correction unit. The comparison unit 32 and the current source gate logic conversion unit 33 constitute a converter PWM modulation signal generation unit, and the comparison unit 44 and the OR operation unit 45 constitute an inverter PWM modulation signal generation unit. .

で表される相電圧指令信号Ｖ_u ^***,Ｖ_v ^***,Ｖ_w ^***と同様に、台形波状電圧指令信号Ｖ_r ^*,Ｖ_s ^*,Ｖ_t ^*の傾斜領域における値を予めテーブルとして設定しておく。ここで、位相角φは、三相交流入力電圧の相電圧ｖ_rに同期している。 The trapezoidal wave voltage command generation unit 31 generates a slope region of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* using a predetermined table. Here, the equation (8) described in FIGS. 5A to 5C, that is,

In the same way as the phase voltage command signals V _u ^*** , V _v ^*** , V _w ^*** represented by the values in the slope region of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* Are set in advance as a table. Here, the phase angle φ is synchronized with the phase voltage v _r of the three-phase AC input voltage.

Note that the slope regions of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , and V _t ^* may be obtained using equations instead of the table.

(ただし、位相角φは０≦φ≦π／３)

(ただし、位相角φはπ≦φ≦４π／３)
の所定の式を用いて、台形波状電圧指令信号Ｖ_r ^*,Ｖ_s ^*,Ｖ_t ^*の傾斜領域を夫々求める。これにより、演算負荷を低減しつつ、歪のない三相交流出力電圧(電流)を確実に得ることができる。 That is,

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
The slope regions of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , and V _t ^* are obtained using the predetermined formulas (1). Thereby, it is possible to reliably obtain a three-phase AC output voltage (current) without distortion while reducing the calculation load.

According to the matrix converter having the above-described configuration, the pulsating voltage (current) waveform of the virtual DC voltage converted by the virtual converter unit is instructed not to cause distortion in the three-phase AC output voltage (current). The signal correcting unit (34, 42, 43) corrects the output voltage command signal, and based on the corrected output voltage command signal, the virtual inverter unit converts the virtual DC voltage converted by the virtual converter unit to a predetermined value. Convert to three-phase AC output voltage. At this time, the trapezoidal wave voltage command generation unit 31 generates the slope region of the trapezoidal wave voltage command signals V _r ^* , V _s ^* , V _t ^* by using a predetermined table (or a predetermined expression), The calculation load on the control unit can be reduced with a simple configuration.

  By enabling PWM modulation with one carrier signal common to the virtual converter unit and the virtual inverter unit, the circuit of the control unit can be simplified.

  In the first and second embodiments described above, the direct-type power conversion device in which the trapezoidal wave voltage command signal obtained by using the table or the equation to obtain the slope region is applied to the converter side has been described. You may apply this invention to the power converter device applied to the side. The power converter which applied this trapezoidal wave voltage command signal to the inverter side by the following 3rd, 4th embodiment is demonstrated.

[Third Embodiment]
FIG. 10 shows a configuration diagram of a power conversion device according to the third embodiment of the present invention.
As shown in FIG. 10, the power conversion device according to the third embodiment includes a voltage output voltage source converter 101 as an example of a converter unit that converts a three-phase AC voltage from a three-phase AC power source 100 into a DC voltage; An inverter unit 102 that converts a DC voltage from the voltage output voltage source converter 101 and outputs a desired three-phase AC voltage to the motor 103; and a control unit that controls the voltage output voltage source converter 101 and the inverter unit 102 110.

The inverter unit 102, the output terminal of the phase voltage v _r of the three-phase AC output voltage is connected to the collector of the emitter and the transistor S _rn of the transistors S _rp, emitter and transistor of the phase voltage v _s transistor S _sp to the output terminal of the a collector connected to S _sn, connects the collector of the emitter and the transistor S _tn of the transistor S _tp to the output terminal of the phase voltage v _t. The transistors S _rp, S _sp, while each connecting collectors of S _tp the first DC link section L101, are respectively connected transistors S _rn, S _sn, the emitter of S _tn the second DC link section L102. Further, diodes D _rp , D _sp , D _tp are respectively connected in the opposite direction between the collectors and emitters of the transistors S _rp , S _sp , S _tp , and the collectors of the transistors S _rn , S _sn , _{St n} Diodes D _rn , D _sn , and D _tn are respectively connected in the opposite directions between the emitter and the emitter.

  Further, the control unit 110 is based on the pulsating voltage command generation unit 104 that outputs a pulsating voltage command signal to the voltage output voltage source converter 101 based on the amplitude command ks and the phase command θ, and on the basis of the phase command θ. , A trapezoidal phase voltage command generation unit 105 that generates a trapezoidal phase voltage command signal, and a PWM modulation signal is output to the inverter unit 102 based on the trapezoidal phase voltage command generation unit 105 And a PWM modulator 106. The PWM modulation unit 106 includes a carrier signal generation unit 106a.

  Here, the trapezoidal phase voltage command generation unit 105 includes a trapezoidal wave voltage command signal generation unit 11 illustrated in FIG. 1 of the first embodiment and a trapezoidal wave voltage command signal generation unit 31 illustrated in FIG. 2 of the second embodiment. Similarly, the slope area of the trapezoidal wave voltage command signal is generated using a predetermined table, or the slope area of the trapezoidal wave voltage command signal is obtained using an expression instead of the table. Thereby, it is possible to reliably obtain a three-phase AC output voltage (current) without distortion while reducing the calculation load.

  FIG. 12 shows the command waveform of the power converter, FIG. 12 (a) shows the amplitude command waveform, and FIG. 12 (b) shows the phase voltage command waveform. FIG. 12C shows the waveform of a line current command when a current source converter is used instead of the voltage output voltage source converter 101 shown in FIG.

[Fourth Embodiment]
FIG. 11 shows a configuration diagram of a power conversion device according to the fourth embodiment of the present invention.

  As shown in FIG. 11, the power conversion device according to the fourth embodiment includes a current output current source converter 201 as an example of a converter unit that converts a three-phase AC voltage from a three-phase AC power source 200 into a DC voltage; An inverter unit 202 that converts a DC voltage from the current output current source converter 201 and outputs a desired three-phase AC voltage to the motor 203, and a control unit that controls the current output current source converter 201 and the inverter unit 202 210. One end of the first DC link portion L201 is connected to the positive terminal of the current output current source converter 201, while one end of the second DC link portion L202 is connected to the negative terminal of the current output current source converter 201. Yes.

The inverter unit 202, the transistor S _rp to the first DC link section L201, connect the collector of the S _sp, S _tp, transistor S _rp, S _sp, emitter diode D _rp of S _tp, D _sp, of D _tp The anodes are connected to each other. The cathodes of the diodes D _rp , D _sp and D _tp are connected to the output terminals of the phase voltages v _r , v _s and v _t , respectively. On the other hand, each transistor S _rn, S _sn, and respectively connected to the emitter of the S _tn the second DC link section L202, transistors S _rn, S _sn, diode D _rn to the collector of the S _tn, D _sn, the cathode of D _tn s Connected. The anodes of the diodes Drn, Dsn, and Dtn are connected to the output terminals of the phase voltages v _r , v _s , and v _t , respectively.

  Further, the control unit 210 is configured to output a pulsating current command signal 204 to the current output current source converter 201 based on the amplitude command ks and the phase command θ, and based on the phase command θ. A trapezoidal phase voltage command generation unit 205 that generates a trapezoidal phase voltage command signal and a PWM modulation unit 207 that outputs a PWM modulation signal based on the trapezoidal phase voltage command generation signal from the trapezoidal phase voltage command generation unit 205. And a current-type logic conversion unit 206 that logically converts the PWM modulation signal from the PWM modulation unit 207 and outputs the converted signal to the inverter unit 202. The PWM modulation unit 207 includes a carrier signal generation unit 207a.

  Here, the trapezoidal phase voltage command generation unit 205 includes the trapezoidal wave voltage command signal generation unit 11 illustrated in FIG. 1 of the first embodiment and the trapezoidal wave voltage command signal generation unit 31 illustrated in FIG. 2 of the second embodiment. Similarly, the slope area of the trapezoidal wave voltage command signal is generated using a predetermined table, or the slope area of the trapezoidal wave voltage command signal is obtained using an expression instead of the table. Thereby, it is possible to reliably obtain a three-phase AC output voltage (current) without distortion while reducing the calculation load.

  FIG. 12 shows the command waveform of the power converter, FIG. 12 (a) shows the waveform of the amplitude command, and FIG. 12 (b) shows the waveform of the phase current command. FIG. 12C shows a line current command value converted by the current source logic conversion unit 206 of FIG. 11 and given to the inverter unit 202.

で表される空間ベクトル変調方式の基本式を用いて、電圧ベクトルの出力時間を決定することによって、ＰＷＭ波形生成を行うこともできる。 In the power converters of the third and fourth embodiments,

The PWM waveform generation can also be performed by determining the output time of the voltage vector using the basic expression of the space vector modulation method expressed by

FIG. 1 is a configuration diagram of a direct power converter according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a direct power converter according to a second embodiment of the present invention. FIG. 3 is a configuration diagram of a direct conversion circuit with a DC link. FIG. 4 is a diagram showing waveforms at various parts for explaining the control principle of the direct conversion circuit with a DC link. FIG. 5A is a diagram showing a line voltage control waveform. FIG. 5B is a diagram showing a trapezoidal wave modulation waveform (phase voltage). FIG. 5C is a diagram showing a trapezoidal wave modulation waveform (line voltage). FIG. 6A is a diagram for explaining space vector modulation. FIG. 6B is a diagram showing a trapezoidal wave modulation waveform (phase voltage) in space vector modulation. FIG. 6C is a diagram showing a trapezoidal wave modulation waveform (line voltage) in space vector modulation. FIG. 7 is a diagram showing a synchronous PWM modulation method for comparison. FIG. 8 is a diagram showing a PWM modulation method using a triangular wave carrier signal of the direct power converter of the present invention. FIG. 9 is a diagram showing a PWM modulation method using a sawtooth carrier signal of the direct power converter according to the present invention. FIG. 10 is a configuration diagram of a power conversion device according to a third embodiment of the present invention. FIG. 11 is a configuration diagram of the power conversion device according to the fourth embodiment of the present invention. FIG. 12 is a diagram showing a command waveform of the power converter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Converter part 2 ... Inverter part 3 ... Control part 4 ... Conversion part 5 ... Control part 11 ... Trapezoid wave-shaped voltage command generation part 12 ... Comparison part 13 ... Current source gate logic conversion part 14 ... Intermediate phase detection part 15 ... Carrier signal Generation unit 21 ... Output voltage command signal generation unit 22 ... Calculation unit 23 ... Calculation unit 24 ... Comparison unit 25 ... Logical sum calculation unit 31 ... Trapezoidal wave voltage command generation unit 32 ... Comparison unit 33 ... Current source gate logic conversion unit 34 ... Intermediate phase detection unit 35 ... carrier signal generation unit 41 ... output voltage command signal generation unit 42 ... calculation unit 43 ... calculation unit 44 ... comparison unit 45 ... logical sum calculation unit 50 ... gate signal synthesis unit 100 ... three-phase AC power supply 101 ... Voltage output voltage type converter 102 ... Inverter unit 103 ... Motor 104 ... Pulsating flow voltage command generation unit 105 ... Trapezoid phase voltage command generation unit 106 ... PWM modulation unit 106a ... Carrier signal Signal generation unit 110 ... Control unit 200 ... Three-phase AC power supply 201 ... Current output current source converter 202 ... Inverter unit 203 ... Motor 204 ... Pulse current command generation unit 205 ... Trapezoid phase voltage command generation unit 206 ... Current source logic Conversion unit 207 ... PWM modulation unit 207a ... carrier signal generation unit 210 ... control unit

Claims (7)

A converter unit (1) that converts a three-phase AC input voltage into a DC voltage, and an inverter unit (2) that converts the DC voltage converted by the converter unit (1) into a predetermined three-phase AC output voltage. A power conversion device that does not have a smoothing filter in a DC link unit that connects the converter unit (1) and the inverter unit (2),
A converter unit command signal generation unit (11, 31) for generating a trapezoidal wave-shaped converter unit command signal based on a phase angle of a reference signal generated so as to be synchronized with the three-phase AC input voltage;
A carrier signal generator (15, 35) for generating a carrier signal;
An inverter command signal generator (21, 41) for generating an inverter command signal for outputting the predetermined three-phase AC output voltage;
The trapezoidal converter unit command signal from the converter unit command signal generation unit (11, 31) is a three-phase command signal represented by a phase voltage, and two of the three-phase command signals. An intermediate phase detector (14, 34) for detecting a current-flow ratio of the intermediate phase, which is another one-phase command signal that is switched when the phase command signal indicates a conduction state;
The intermediate phase from the intermediate phase detection unit (14, 34) so that the inverter unit (2) can perform pulse width modulation using the same carrier signal as that used in the converter unit (1). Based on the current flow ratio, the amplitude of the inverter command signal from the inverter command signal generator (21, 41) is corrected, and the intermediate phase of the corrected inverter command signal is corrected. The polarity of the other command signal represented by the current ratio by providing an offset to one command signal represented by the current ratio for two switching states between the current state and the other two phases of the conductive state And a calculation unit (22, 23, 42, 43) for inverting
The converter unit (1) is configured such that the trapezoidal converter unit command signal from the converter unit command signal generation unit (11, 31) and the carrier signal from the carrier signal generation unit (15, 35). By the pulse width modulation method based on the comparison result, the three-phase AC input voltage is converted to the DC voltage,
The inverter unit (2) compares the inverter unit command signal corrected by the arithmetic unit (22, 23, 42, 43) and the carrier signal from the carrier signal generation unit (15, 35). The DC voltage converted by the converter unit (1) is converted into the predetermined three-phase AC output voltage by a pulse width modulation method based on
The converter unit command signal generation unit (11, 31) is configured such that the slope region of the trapezoidal converter unit command signal is

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
The power conversion device is generated using a predetermined expression represented by the following expression, or is generated using a table preset based on the predetermined expression. The power conversion device according to claim 1 ,
By comparing the converter unit command signal from the converter unit command signal generation unit (11, 31) with the carrier signal from the carrier signal generation unit (15, 35), the converter unit PWM modulation signal is obtained. A PWM modulation signal generation unit (12, 13, 32, 33) for the converter unit to be generated;
The inverter unit command signal from the inverter unit command signal generation unit (21, 41) is compared with the carrier signal identical to that used in the converter unit (1), and PWM modulation for inverter unit is performed. A PWM modulation signal generation unit (24, 25, 44, 45) for an inverter unit for generating a signal,
The converter unit (1) converts the three-phase AC input voltage to the DC voltage based on the converter unit PWM modulation signal generated by the converter unit PWM modulation signal generation unit (12, 13, 32, 33). Converted to
The inverter unit (2) is converted by the converter unit (1) based on the inverter unit PWM modulation signal generated by the inverter unit PWM modulation signal generation unit (24, 25, 44, 45). And converting the DC voltage into the predetermined three-phase AC output voltage. The power conversion device according to claim 2 ,
The power conversion apparatus according to claim 1, wherein the carrier signal is a triangular wave signal. The power conversion device according to claim 2 ,
The power converter according to claim 1, wherein the carrier signal is a sawtooth signal. The power conversion device according to claim 1 ,
The converter part (1)
Three switching circuits (S _rp , S _sp , S _tp ) in which each phase voltage of the three-phase AC input voltage is input to one end and the other end is connected to the first DC link unit;
Each phase voltage of the three-phase AC input voltage is input to one end, and three switching circuits (S _rn , S _sn , _{St n} ) each having the other end connected to the second DC link unit,
The inverter part (2)
Three switching circuits (S _up , S _vp , S _wp ) in which each output terminal of the predetermined three-phase AC output voltage is connected to one end, and the other end is connected to the first DC link unit;
Each switching terminal (S _un , S _vn , S _wn ) has each output terminal of the predetermined three-phase AC output voltage connected to one end and the other end connected to the second DC link section. The power converter characterized by the above-mentioned. The power conversion device according to claim 1 ,
A matrix converter having a virtual converter unit corresponding to the converter unit, a virtual inverter unit corresponding to the inverter unit, and a virtual DC link unit corresponding to the DC link unit,
The virtual converter unit and the virtual inverter unit are
Of the three-phase AC input voltage, a first phase voltage is input to one end, and three switching circuits ( _Sur , _Svr) each having the other end connected to each output terminal of the predetermined three-phase AC output voltage. , S _wr )
Of the three-phase AC input voltage, a second phase voltage is input to one end, and three switching circuits (S _us , S _vs , each having the other end connected to each output terminal of the predetermined three-phase AC output voltage. , S _ws ) and
Three switching circuits (S _ut , S _vt) in which the third phase voltage of the three-phase AC input voltage is input to one end and the other end is connected to each output terminal of the predetermined three-phase AC output voltage. , S _wt ). A converter unit (1) that converts a three-phase AC input voltage into a DC voltage, and an inverter unit (2) that converts the DC voltage converted by the converter unit (1) into a predetermined three-phase AC output voltage. A control method for a power conversion device that does not have a smoothing filter in a DC link unit connecting the converter unit (1) and the inverter unit (2),
Generating a trapezoidal wave-shaped command signal for the converter unit by the converter unit command signal generation unit (11, 31) based on the phase angle of the reference signal generated so as to be synchronized with the three-phase AC input voltage;
Generating a carrier signal by the carrier signal generator (15, 35);
Generating an inverter unit command signal for outputting the predetermined three-phase AC output voltage by the inverter unit command signal generation unit (21, 41);
The trapezoidal converter unit command signal from the converter unit command signal generation unit (11, 31) is a three-phase command signal represented by a phase voltage, and two of the three-phase command signals. Detecting a current flow ratio of the intermediate phase, which is another one-phase command signal that is switched when the phase indicates a conduction state, by the intermediate phase detector (14, 34);
The intermediate phase from the intermediate phase detection unit (14, 34) so that the inverter unit (2) can perform pulse width modulation using the same carrier signal as that used in the converter unit (1). Based on the current flow ratio, the calculation unit (22, 23, 42, 43) corrects the amplitude of the inverter unit command signal from the inverter unit command signal generation unit (21, 41). In addition, with respect to two switching states between the intermediate phase and the other two phases of the conduction state among the inverter unit command signals, one command signal represented by the conduction ratio is offset to provide the switching Reversing the polarity of the other command signal represented by the flow ratio;
Pulse width modulation system based on the comparison result between the trapezoidal converter command signal from the converter command signal generator (11, 31) and the carrier signal from the carrier signal generator (15, 35) The converter unit (1) converts the three-phase AC input voltage into the DC voltage;
By the pulse width modulation method based on the comparison result between the inverter unit command signal corrected by the arithmetic unit (22, 23, 42, 43) and the carrier signal from the carrier signal generation unit (15, 35), Converting the DC voltage converted by the converter unit (1) into the predetermined three-phase AC output voltage by the inverter unit (2),
In the step of generating the trapezoidal converter command signal by the converter unit command signal generator (11, 31), the slope region of the trapezoidal converter unit command signal is:

(However, the phase angle φ is 0 ≦ φ ≦ π / 3)

(However, phase angle φ is π ≦ φ ≦ 4π / 3)
A method for controlling the power conversion device, wherein the power conversion device is generated using a predetermined expression expressed by the following equation or a table preset based on the predetermined expression.

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