JP2013258869A - Single-phase/three-phase converter and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress distortion in the three-phase output waveform when the output changes.SOLUTION: A single-phase/three-phase matrix converter includes a capacitor which absorbs the pulsation component of single-phase AC power, and a switching circuit which converts the single-phase AC power into three-phase AC power while performing pulsation compensation by using the generating power of the capacitor. From the output power pand the detection value of power supply voltage e based on the output voltage command value and output current detection value of three-phase AC power, a power supply current reference command value i, a capacitor current reference amplitude (amplitude reference command) Iand a capacitor voltage command value vare derived, and then a capacitor current command value iis obtained by correcting the Iso that the difference between the vand the capacitor voltage detection value vgoes zero. Meanwhile, an input instantaneous power pis obtained based on the e, v, iand i, and the difference Δp from an output instantaneous power pis obtained, and then a power supply current command value iis created by correcting the iso that the Δp goes zero.

Description

  The present invention relates to a single-phase / three-phase converter and a control method thereof.

  In single-phase / three-phase power conversion, a single-phase AC voltage is first converted to a DC voltage using a rectifier circuit and a large-capacity electrolytic capacitor, and then a DC voltage is often converted to a three-phase AC voltage using an inverter. . However, the electric field capacitor is large and has a short life. In consideration of this, in recent years, a single-phase / three-phase matrix converter capable of directly converting a single-phase alternating current into a three-phase alternating current has been proposed. Has been.

FIG. 3 shows a model of a conventional single-phase / three-phase matrix converter corresponding to the disclosure of Non-Patent Document 2, and FIG. 4 shows a configuration of an input current command value calculation block based on the model. In the model of FIG. 3, a filter circuit that should be provided between the single-phase AC power supply 901 and the switching circuit 902 is omitted. The switching circuit 902 includes nine bidirectional switches that individually conduct / non-conduct between each of the r, s, and t phase input lines and each of the u, v, and w phase output lines. A single-phase AC voltage from the single-phase AC power source 901 is applied between r and t-phase input lines. The power pulsation compensation capacitor 904 is for compensating for the pulsation of instantaneous power of single-phase alternating current. The capacitor 904 is connected between the s and t phase input lines and absorbs the pulsating component of the single phase AC power via the switching circuit 902. 3 and FIG. ^{_{4, i r *, i s}} * and i _t ^* is, r, represents the command value of the input current of the s and t phases, v _st ^*, the capacitor voltage (the voltage of the capacitor 904) v represents the command value of _st . C _C is the capacitance of the capacitor 904.

Three-phase AC output voltage command values v _uv ^* , v _vw ^* and v _wu ^* corresponding to the output to the three-phase load 903 are calculated, and the output voltage command values v _uv ^* , v _vw ^* and v _wu ^* Based on the detected output current values i _u , i _v and i _w , the output power p _out of the switching circuit 902 is calculated. Further, the effective value E and the phase θ of the power supply voltage e are calculated. The calculation block in FIG. 4 calculates the power supply current command value i _r ^* according to the following formula (A1). As understood from the equation (A1), i _r ^* has an amplitude such that the average value of the instantaneous output power of the power source 901 is equal to the output power p _out , and the power factor of the power source 901 is 1. It has a phase like this.

On the other hand, the calculation block of FIG. 4 calculates the capacitor current reference command value i _sb ^* according to the following formula (A2) so that the power canceling the pulsation in the output instantaneous power of the power source 901 is generated by the capacitor 904. The capacitor voltage command value v _st ^* is calculated according to the following formula (A3).

The calculation block of FIG. 4 takes in the capacitor voltage v _st detected by a voltage detection unit (not shown), and uses the capacitor integral reference so that the difference (v _st ^* −v _st ) becomes zero using proportional integral control. subjected to correction value .DELTA.i _s ^* by the correction of the command value i _sb ^*, we obtain the capacitor current command value i _s ^*. By performing such calculation, it is possible to absorb and compensate the pulsation of the single-phase alternating current power with the instantaneous power of the capacitor 904.

JP 2005-160257 A

Yamashita et al., "PWM control of single-phase / three-phase matrix converter", IEEJ Technical Report, 2010, PE-10-011, PSE-10-010, SPC-10-034 Yamashita et al., “Driving PM Synchronous Motor with Single-Phase / Three-Phase Matrix Converter”, IEEJ Technical Report, 2011, PE-11-009, PSE-11-026, SPC-11-063

Consider the case where the output power p _out is changed with reference to the steady state in which the output power p _out is kept constant in the models of FIGS. 3 and 4. When the output power p _out has changed, i _r ^* which is dependent on the output power ^{_{p out, i s *, i}} t * and v _st ^* also changes. However, capacitor voltage v _st is because it is indirectly controlled by the capacitor current i _s, the time until the control to the command value v _st ^* as consuming. That is, the capacitor voltage v _st does not become the command value v _st ^* for a certain period from the moment when the output is changed. Since the pulsation compensation is realized on the assumption that the capacitor voltage v _st matches the command value v _st ^* , the pulsation of the single-phase AC instantaneous power is converted into the instantaneous power of the capacitor 904 in the certain period. Cannot be fully compensated. As a result, input / output power imbalance occurs, leading to distortion of the three-phase output waveform.

  Therefore, an object of the present invention is to provide a single-phase / three-phase conversion device that contributes to suppression of distortion of a three-phase output waveform and a control method thereof.

  The single-phase / three-phase converter according to the present invention includes a capacitor unit for compensating for pulsation of instantaneous power of a single-phase AC output from a single-phase AC power source, and the compensation using the generated power of the capacitor unit. A switching unit that converts single-phase AC power from the single-phase AC power source into three-phase AC power, and a control unit that controls the switching unit, and the control unit is configured to control the single-phase AC power. When the pulsating component includes a non-compensation component that is not compensated by the power generated by the capacitor unit, the input power from the single-phase AC power source to the switching unit is corrected according to the non-compensation component.

  If there is a non-compensation component, an imbalance may occur between the input and output power of the switching unit, and the three-phase output waveform may be distorted. By correcting, the above-mentioned imbalance can be eliminated, and distortion of the three-phase output waveform can be suppressed.

  Further, for example, the control unit may prohibit the correction of the input power when the output voltage of the single-phase AC power supply is a predetermined value or less.

  Further, for example, the control unit controls the switching unit in response to a request for output to a load connected to the switching unit, so that the three-phase AC power corresponding to the request is output from the switching unit. In a section where the output voltage of the single-phase AC power supply is below a predetermined value, when there is a request for an output change to the load, the execution timing of the control according to the request for the output change is delayed to the outside of the section. Also good.

  Specifically, for example, the control unit converts the differential power between the input instantaneous power supplied from the single-phase AC power source and the capacitor unit to the switching unit and the output instantaneous power of the switching unit as the non-compensation component. The input power from the single-phase AC power supply to the switching unit may be corrected so that the differential power is reduced.

More specifically, for example, the control unit is based on the output power of the switching unit and the output voltage of the single-phase AC power supply, and a reference command value for the output current of the single-phase AC power supply, and for the output current of the capacitor unit. A first calculation unit that derives a reference command value and a command value for the output voltage of the capacitor unit; and a command value for the output voltage of the capacitor unit and an actual output voltage of the capacitor unit, with respect to the output current of the capacitor unit A second calculation unit for deriving a command value for the output current of the capacitor unit through a process of correcting a reference command value;
Based on the output voltage of the single-phase AC power source, the actual output voltage of the capacitor unit, the command value for the output current of the capacitor unit, and the reference command value for the output current of the single-phase AC power source, the input instantaneous power is obtained. A third calculation unit for deriving the differential power from the input instantaneous power and the output instantaneous power; and correcting the reference command value for the output current of the single-phase AC power supply so that the differential power is reduced. A fourth calculation unit that derives a command value for the output current of the AC power supply, and the input power from the single-phase AC power supply to the switching unit may be corrected by the correction of the fourth calculation unit.

  In addition, for example, the single-phase / three-phase converter further includes first to third input lines interposed between the switching unit, the single-phase AC power source, and the capacitor unit, from the single-phase AC power source A single-phase AC voltage is applied between the first and third input lines, the capacitor unit is connected between the second and third input lines, and the single-phase AC power is supplied via the switching unit. The pulsating component may be absorbed, and the switching unit may generate the three-phase AC power based on power input from the single-phase AC power source and the capacitor unit via the first to third input lines.

  A method for controlling a single-phase / three-phase converter according to the present invention uses a capacitor unit for compensating for a pulsation of instantaneous power of a single-phase AC output from a single-phase AC power source, and generated power of the capacitor unit. A switching unit that converts single-phase AC power from the single-phase AC power source into three-phase AC power while performing the compensation, and a control method for a single-phase / three-phase converter, comprising: When the pulsating component of power includes a non-compensation component that is not compensated by the power generated by the capacitor unit, the input power from the single-phase AC power supply to the switching unit is corrected according to the non-compensation component. To do.

  If there is a non-compensation component, an imbalance may occur between the input and output power of the switching unit, and the three-phase output waveform may be distorted. By correcting, the above-mentioned imbalance can be eliminated, and distortion of the three-phase output waveform can be suppressed.

  For example, the control method may prohibit the correction of the input power when the output voltage of the single-phase AC power supply is a predetermined value or less.

  Further, for example, the control method controls the switching unit in response to a request for output to a load connected to the switching unit, so that the three-phase AC power corresponding to the request is output from the switching unit. In a section where the output voltage of the single-phase AC power supply is below a predetermined value, when there is a request for an output change to the load, the execution timing of the control according to the request for the output change is delayed to the outside of the section. Also good.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the single phase / three phase converter which contributes to suppression of the distortion of a three-phase output waveform, and its control method.

1 is an overall configuration diagram of a single-phase / three-phase matrix converter system according to an embodiment of the present invention. It is a figure which shows the structure of the input electric current command value calculating block which concerns on embodiment of this invention. It is a model diagram of a conventional single-phase / three-phase matrix converter. It is a figure which shows the structure of the input electric current command value calculation block based on the model of FIG.

Hereinafter, an example of an embodiment of the present invention will be specifically described with reference to the drawings. The description given above with reference to FIGS. 3 and 4 is not applied to the present embodiment, and the description in the present embodiment is applied when interpreting the configuration and operation of the present embodiment (thus, for example, i _s ^* of i _s ^* and the embodiment of FIG. 4 is separate). In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle. In this specification, for simplification of description, a symbol or reference that refers to information, signal, physical quantity, state quantity, member, or the like is written to indicate information, signal, physical quantity, state quantity or Names of members and the like may be omitted or abbreviated. Further, in this specification, a symbol or code that refers to the name of a certain physical quantity is also used as a symbol or code that refers to the value of the physical quantity. That is, for example, when a certain current is referred to by the symbol i _u , the value of the current is also referred to by the symbol i _u .

  FIG. 1 is an overall configuration diagram of a single-phase / three-phase matrix converter system 1 incorporating a single-phase / three-phase matrix converter device 4 which is a kind of single-phase / three-phase converter. A single-phase AC power source 2 that outputs single-phase AC power is connected to the input side of the device 4, and a three-phase load 3 that is driven by three-phase AC power is connected to the output side of the device 4. The type of the three-phase load 3 is arbitrary, but in particular, the three-phase load 3 can be a three-phase balanced load. For example, the three-phase load 3 is a three-phase permanent magnet synchronous motor. In the present embodiment, unless otherwise specified, single-phase alternating current, single-phase alternating current power, single-phase alternating current voltage, and single-phase alternating current refer to those output from the power source 2, and include three-phase alternating current and three-phase alternating current. The electric power, the three-phase AC voltage, and the three-phase AC current refer to those output from the switching circuit 7 (in other words, the device 4).

The single-phase / three-phase matrix converter device 4 includes a filter circuit 5, a power pulsation compensation capacitor 6, a switching circuit 7 including nine bidirectional switches, a voltage detection unit 8, a current detection unit 9, and a control unit. 10, r-phase, s-phase and t-phase input lines LN _r , LN _s and LN _t interposed between the power source 2 and the capacitor 6 and the switching circuit 7, the switching circuit 7 and the three-phase load 3. Are provided with output lines LN _u , LN _v and LN _w of u phase, v phase and w phase interposed between them.

A pair of output terminals of the power source 2 are connected to the input lines LN _r and LN _t via the filter circuit 5, and a single-phase AC voltage (hereinafter referred to as “the power source 2”) is output between the input lines LN _r and LN _t . (Referred to as power supply voltage e). The filter circuit 5 is an LC filter including a reactor 5L and a capacitor 5C, and suppresses harmonics generated by switching.

Power pulsation compensation capacitor 6 is interposed in series between the input line LN _s and LN _t. Therefore, the input line LN _s and LN _t, the output voltage of the capacitor 6 is the voltage between the positive electrode and the negative electrode of the capacitor 6 (hereinafter, referred to as a capacitor voltage v _st) is applied. It represents the capacitance of the capacitor 6 at the symbol C _C. The instantaneous power of single-phase AC output from the power source 2 (that is, the instantaneous value of the single-phase AC power) pulsates at twice the frequency of the single-phase AC. The capacitor 6 is for compensating for this pulsation. The capacitor 6 performs the above-described compensation by absorbing the pulsating component of the output single-phase AC power from the power supply 2 via the switching circuit 7. That is, the instantaneous power of the single-phase alternating current output from the power source 2 has a direct current component and a pulsating component. Under the control of the control unit 10, the direct current power is supplied to the three-phase load 3 as three-phase alternating current power. Thus, the pulsating component is absorbed by the capacitor 6. Input line LN _r, the current input to the switching circuit 7 via the LN _s and LN _t, denoted by respectively the symbols i _r, i _s and i _t. Current i _r can be referred to as the power source current (the output current of the power supply 2), the current i _s can be referred to as capacitor current (output current of the capacitor 6).

The switching circuit 7, also referred to as a single-phase / three-phase matrix converter, includes three u-phase bidirectional switches interposed between the input lines LN _r , LN _s and LN _t and the output line LN _u , and the input line LN. _The three v-phase bidirectional switches interposed between each of _r , LN _s and LN _t and the output line LN _v, and between each of the input lines LN _r , LN _s and LN _t and the output line LN _w Three w-phase bidirectional switches interposed between the two. By turning on the bidirectional switch between the input line LN _r and the output line LN _u , the input line LN _r and the output line LN _u are brought into conduction (that is, connected), and the input line LN _r and the output line LN _u are connected. By turning off the bidirectional switch, the input line LN _r and the output line LN _u are rendered non-conductive (that is, disconnected). The same applies to the other eight bidirectional switches. In the switching circuit 7, each bidirectional switch is formed using a semiconductor switching element such as an insulated gate bipolar transistor or a field effect transistor. However, each bidirectional switch may be formed using a mechanical switch.

A three-phase load 3 is connected to the output lines LN _u , LN _v and LN _w . Under the control of the control unit 10, each bidirectional switch of the switching circuit 7 is individually turned on or off, so that the switching circuit 7 converts the single-phase AC power into the three-phase AC power, and the three-phase AC power is It is supplied to the three-phase load 3 via the output lines LN _u , LN _v and LN _w . At this time, pulsation compensation using the capacitor 6 is performed. The three-phase alternating current generated by the switching circuit 7 is a symmetrical three-phase alternating current. The three-phase AC voltage output from the switching circuit 7 is an output line based on the AC voltage v _uv between the output lines LN _u and LN _v based on the potential of the output line LN _{v and} the potential of the output line LN _w. AC voltage v _vw between LN _v and LN _w and AC voltage v _wu between output lines LN _w and LN _u with reference to the potential of output line LN _u .

The voltage detector 8 detects an input voltage to the switching circuit 7. Specifically, the voltage detection unit 8 detects the power supply voltage e input from the power supply 2 to the switching circuit 7 and the capacitor voltage v _st input from the capacitor 6 to the switching circuit 7. It is assumed that the power supply voltage e and the capacitor voltage v _st are voltages based on the potential of the input line LN _t . The current detection unit 9 detects the output current of the switching circuit 7. Specifically, the current detection unit 9 detects the output currents i _u , i _v, and i _w of the switching circuit 7 that flow through the output lines LN _u , LN _v, and LN _w . The output currents i _u , _iv and i _w are currents of u phase, v phase and w phase in the three-phase AC power, respectively.

The control unit 10 includes an AD conversion unit 11, a DSP (Digital Signal Processor) 12, a PWM calculation unit 13, and a gate drive circuit 14. In the control unit 10, a control cycle having a predetermined time length is defined, and each operation is performed for each control cycle. Specifically, the AD conversion unit 11 includes an output analog signal of the voltage detection unit 8 indicating the values of the power supply voltage e and the capacitor voltage _vst , and a current detection unit 9 indicating the values of the output currents i _u , _iv and i _w. The output analog signal is converted to a digital value for each control period, and then supplied to the DSP 12.

The DSP 12 calculates an output voltage command value corresponding to a power output request from the switching circuit 7 to the three-phase load 3, and based on the calculated output voltage command value and the detected output current values i _u , _iv and i _w . The output power p _out for the three-phase load 3 is calculated from the switching circuit 7 and the input current command value is calculated based on the calculated output power p _out and the detected input voltage values e and v _st . The output voltage command value includes command values v _uv ^* , v _vw ^*, and v _wu ^* representing target values of the voltages v _uv , v _vw, and v _wu . Input current command value, ^* command value i _r representing a target value of the current i _r, i _s and i _t, consisting i _s ^* and i _t ^*.

Furthermore, DSP 12 is the input current command value i _r ^*, i _s ^* and i _t ^* and output voltage command value v _uv ^*, v based on _vw ^* and v _wu ^*, for the nine bidirectional switches in the switching circuit 7 The on-time for each control cycle is calculated and output to the PWM calculation unit 13. The on-time for each control cycle calculated here is the length of time during which the bidirectional switch is turned on in one control cycle. The on-time of each of the nine bidirectional switches is obtained and the PWM calculation unit 13 receives the on-time. Sent. The PWM calculation unit 13 generates a gate drive pulse based on the supplied ON time of each bidirectional switch, and the bidirectional drive is turned on and off by the gate drive circuit 14 according to the gate drive pulse. As a result, the actual current or voltage values i _r , i _s , i _t , v _uv , v _vw and v _wu become the command values i _r ^* , i _s ^* , i _t ^* , v _uv ^* , v _vw ^* and v Matched with _wu ^* .

The device 4 has a characteristic characteristic to the calculation operation of the input current command value. The configuration and operation of the input current command value calculation block 50 included in the DSP 12 will be described with reference to FIG. For simplicity of explanation, it is assumed that the loss in the switching circuit 7 is zero. As described above, the pulsation of the instantaneous power of the single-phase alternating current is compensated by the power generated by the capacitor 6 (capacitor power p _c described later). However, in some cases, this compensation may not be performed completely. When this compensation is not performed completely, a power difference corresponding to the uncompensated pulsation component can be generated between the input power (p _in, described later) and the output power p _{out of} the switching circuit 7. The calculation block 50 suppresses this power difference by directly adjusting the input power from the power source 2 to the switching circuit 7. Hereinafter, this method will be described in detail.

The DSP 12 calculates the output voltage command values v _uv ^* , v _vw ^*, and v _wu ^* so that the three-phase AC power corresponding to the output request signal is supplied to the three-phase load 3, and outputs the output voltage command value v _uv ^*. , v is calculated _vw ^* and v _wu ^* and the detected output current value i _u, i _v, and i based on the _w output power p _out. The calculated value of the output power p _out is input to the calculation block 50, and the power supply voltage e and the capacitor voltage v _st detected by the voltage detector 8 are also input to the calculation block 50. The values of the output power p _out , the power supply voltage e, and the capacitor voltage v _st that are input to the calculation block 50 in each control period represent their instantaneous values, and any value derived by the calculation block 50 based on them. The value of the physical quantity represents an instantaneous value of the physical quantity. The output request signal is generated by a block inside the device 4 and outside the control unit 10 or by a host system (not shown) outside the device 4 and given to the control unit 10 and the DSP 12. However, the output request signal may be generated in the DSP 12 or the control unit 10.

  The reference command calculation unit 51 in the calculation block 50 calculates the effective value E and the phase θ of the power supply voltage e based on the power supply voltage value e fetched from the voltage detection unit 8. The effective value E and the phase θ are expressed by the following formula (B1). For example, the effective value E and the phase θ can be calculated based on the power supply voltage value e for a plurality of control periods.

The reference command calculation unit 51 calculates a power supply current reference command value i _rb ^* according to the following formula (B2) based on the effective value E, the phase θ, and the output power p _out . i _rb ^* is a reference current value of the power source current, that is, the command value i _r ^* of the current i _r . As understood from the equation (B2), i _rb ^* has an amplitude such that the average value of the instantaneous output power of the power source 2 is equal to the output power p _out and the power factor of the power source 2 is 1. It has a phase like this.

Further, the reference command calculation unit 51 uses the capacitor current reference amplitude I _sb according to the following formula (B3) so that the capacitor 6 generates electric power that cancels the pulsation in the output instantaneous power (corresponding to p _s described later) of the power source 2. ^* Is calculated. I _sb ^*, the capacitor current, i.e. a reference command value of the amplitude of the current i _s. Furthermore, the reference calculation unit 51 calculates a capacitor voltage command value v _st ^* is a target value of the capacitor voltage v _st according to the following equation (B4), v _st ^* of the absolute value | v _st ^* | outputs a. π is the circumference ratio.

The calculation unit 52 in the calculation block 50 uses the proportional integral control so that the difference between the capacitor voltage v _st detected by the voltage detection unit 8 and the capacitor voltage command value v _st ^* becomes zero (| v _The amplitude correction value ΔI _s ^* based on _st ^* | − | v _st |) is obtained, and the capacitor current amplitude command value I _s ^* is obtained by correcting the capacitor current reference amplitude I _sb ^* with the amplitude correction value ΔI _s ^* . (I _s ^* = I _sb ^* + ΔI _s ^* ). Further, the calculation unit 52 multiplies I _s ^* by a reference wave i _s ′ taking into account the phase for compensating for the above pulsation, thereby generating a command value i _s ^* that is a capacitor current command value. That is, i _s ^* = I _s ^* × i _s ′, and the reference wave i _s ′ is expressed by the following formula (B5). The block 60 shown in FIG. 2 represents the transfer function between the current i _s and the capacitor voltage v _st which can be considered to coincide with the command value i _s ^*. The block 60 is not provided in the calculation block 50 in the DSP 12 (the block 60 does not obtain v _st by calculation using i _s ^* ).

The calculation unit 53 in the calculation block 50 converts the detection value of the power supply voltage e, the detection value of the capacitor voltage _vst , the power supply current reference command value i _rb ^*, and the capacitor current command value i _s ^* by the voltage detection unit 8. prompted instantaneous power p _in based, obtains the power difference Δp by taking the difference between the input instantaneous power p _in and the output instantaneous power p _out. Input instantaneous power p _in represents the instantaneous value of the power input from the power supply 2 and the capacitor 6 to the switching circuit 7.

More specifically, for example, the arithmetic unit 53 obtains an instantaneous value p _s of input power from the power source 2 to the switching circuit 7 according to the equation “p _s = i _rb ^* × e”, and also calculates the equation “p _c = i _s ^* × v _st "obtains instantaneous values p _c of the power input from the capacitor 6 to the switching circuit 7 in accordance with the equation" prompt instantaneous power p _in by _{p in = p s + p c} ". Then, the arithmetic unit 53, based on the output instantaneous power p _out is the instantaneous value of the output power p _out and input the instantaneous power p _in, determining the power difference Delta] p according to the equation _{"Δp = p out -p in"} . The power difference Δp is generated due to a capacitor voltage error (v _st ^* −v _st ) and correction by ΔI _S ^* in the calculation unit 52.

Computing section 54 computing block 50 calculates a correction value .DELTA.i _r ^* with respect to the command value i _rb ^* by dividing the power difference Δp in the detected value of power supply voltage e, command value i _rb ^* the correction value .DELTA.i _r ^* Is added to obtain a command value i _r ^* which is a command value of the power supply current. That is, Δi _r ^* = Δp / e and i _r ^* = i _rb ^* + Δi _r ^* . The calculation block 50, the equation ^{_{"i t * = - (i}} r * + i s *)" command value i _t ^* is also obtained by. Input current command as described above value i _r ^*, by obtaining the i _s ^* and i _t ^*, even under circumstances capacitor voltage error (v _st ^* -v _st) is not zero, the input and output of the switching circuit 7 The difference between power (ie, Δp) can be eliminated.

Consider a case where the output power p _out is changed with reference to the steady state where the output power p _out is kept constant. When the output power p _out is changed from a certain first power value to another second power value, the values of i _rb ^* , I _sb ^* and v _st ^* depending on the output power p _out are the first power values. It instantaneously changes from a value corresponding to the value to a value corresponding to the second power value. However, after the change of i _rb ^* , I _sb ^* and v _st ^* is completed, the capacitor voltage v _st does not have the value of v _st ^* after the change unless a certain period of time elapses. That is, a non-zero capacitor voltage error (v _st ^* −v _st ) occurs after the completion of changes in i _rb ^* , I _sb ^*, and v _st ^* before a certain time has elapsed. Capacitor voltage v _st is because is indirectly controlled by the capacitor current i _s.

The correction by [Delta] I _S ^* for reducing the occurrence and capacitor voltage error of the capacitor voltage error, the instantaneous value p _c of generating power of the capacitor 6 will shift from the desired value. The desired value here is the instantaneous value of the electric power generated by the capacitor 6 for completely compensating for the pulsation of the instantaneous electric power of the single-phase alternating current. Accordingly, the deviation in the instantaneous value p _c of generating power of the capacitor 6, the non-compensation component will occur. The non-compensation component is a power component that can be included in the pulsation component of the single-phase AC power and cannot be compensated for by the generated power of the capacitor 6, and is obtained as a power difference Δp. The calculation block 50 corrects the input power from the power supply 2 to the switching circuit 7 so that the power difference Δp is reduced (typically, Δp is zero). Specifically, correction according to the power difference Δp is performed on the power supply current i _r by performing correction using Δi _r ^* in the process of generating the command value i _r ^* of the power supply current. As a result, the imbalance between the input and output power of the switching circuit 7 is eliminated, and the output waveform distortion of the switching circuit 7 that can occur when the output changes can be reduced.

It can be said that the following operation is performed in the calculation block 50.
Calculation unit 51 based on the detection value of the output power (output instantaneous power) p _out and the power supply voltage e of the switching circuit 7, the reference command value i _rb ^* to the output current i _r power 2, reference command for capacitor current i _s A command value v _st ^* for the value (reference amplitude command value) I _sb ^* and the output voltage of the capacitor 6 is derived.
Calculation unit 52, based on the actual output voltage value v _st command values v _st ^* and the capacitor 6 to the output voltage of the capacitor 6, the reference command value for capacitor current i _s (reference amplitude command value) I _sb ^* correction Through the process, the final command value i _s ^* for the capacitor current i _s is derived.
Calculation unit 53, the detected value of power supply voltage e, the actual output voltage value v _st capacitor 6, the command value i _s for capacitor current i _s ^*, based on the reference command value i _rb ^* to the output current i _r Power 2 seeking input instantaneous power p _in, to derive the differential power Δp between the input instantaneous power p _in and output instantaneous power p _out.
The calculation unit 54 corrects the reference command value i _rb ^* for the output current i _r of the power source 2 so that the differential power Δp decreases, thereby _obtaining a final command value i _r ^* for the output current i _r of the power source 2. To derive. The input power (input current i _r ) from the power source 2 to the switching circuit 7 is corrected by the correction of the calculation unit 54.

Further, when the value of the power supply voltage e there is a change in the output for the three-phase load 3 when in the vicinity of zero, eliminating imbalance between input and output power caused by the effect of the capacitor voltage error correction of the power supply current i _r If this is attempted, the correction value Δi _r ^* becomes considerably large. Therefore, it is not preferable correction of the power supply current i _r at the time when the value of the power supply voltage e is near zero. Considering this, the calculation unit 54 compares the absolute value | e | of the detected value of the power supply voltage e with a predetermined threshold value e _TH (e _TH > 0), and the absolute value | e | is equal to or less than the threshold value e _TH . on one occasion, by the correction of the power supply current i _r, it is preferable to prohibit correction of the input power to the switching circuit 7 from the power supply 2.

More specifically, the calculation unit 54 forcibly sets the correction value Δi _r ^* to zero even if Δp ≠ 0 in the first interval in which the absolute value | e | is equal to or less than the threshold value e _TH. Thus, the reference command value i _rb ^* may be generated and output as i _r ^* as it is. In the second interval in which the absolute value | e | is larger than the threshold value e _TH , the calculation unit 54 adds the correction value Δi _r ^* corresponding to Δp to the reference command value i _rb ^* as a rule. i _r ^* is generated.

When the DSP 12 receives an output change request for the three-phase load 3, the DSP 12 responds so as to satisfy the request. In this response, a capacitor voltage error is remarkably generated. On the other hand, as described above, it is not desirable to correct the power supply current i _r when the value of the power supply voltage e is near zero. Therefore, when the request for changing the output of the switching circuit 7 is received, if the value of the power supply voltage e is near zero, the DSP 12 may temporarily hold the response to the request. In this regard, a specific operation example will be described.

First, the description of the operation according to the output request signal will be supplemented. The DSP 12 (control unit 10) controls the switching circuit 7 in response to an output request signal for requesting power output to the three-phase load 3, so that the three-phase AC power corresponding to the request is transmitted from the switching circuit 7 to the three-phase. Output to load 3. The output request signal includes a signal designating the target physical quantity. The target physical quantity is, for example, the magnitude of output power to be supplied from the switching circuit 7 to the three-phase load 3. When the three-phase load 3 is a three-phase permanent magnet synchronous motor, the target physical quantity can be the rotational speed or generated torque of the motor. Output voltage command value v _uv ^*, v _vw ^* and v _wu ^* and the input current command value i _r ^*, i _s ^* and i _t ^* is dependent on the target physical quantity, the value of the target physical quantity changes if changes.

Now, the output request signal changes from the first output request signal to the second output request signal at a certain specific timing, and as a result, the value of the target physical quantity specified by the output request signal is changed from the value VAL _{1 at the} specific timing. consider a case in which the change to the value VAL _2. At this specific timing, the DSP 12 compares the absolute value | e | of the detected value of the power supply voltage e with a predetermined threshold value e _TH .

If the absolute value | e | is larger than the threshold value e _TH , that is, if the specific timing belongs to the second section, the DSP 12 accepts the change of the output request signal as it is, and sets the value of the target physical quantity to the value VAL. Change corresponding control for changing from ₁ to the value VAL ₂ is executed from a specific timing. Change response control is required to change the value of the target physical quantity from a value VAL ₁ to the value VAL _2, various command values ^{_{(e.g., v uv *, v vw *}} , v wu *, i r *, i s ^* including changes in and a i _t ^*).

On the other hand, the absolute value | e | is equal to or smaller than the threshold value e _TH, that is, the specific timing if belongs to the first period, DSP 12 is the absolute value | e | first until greater than the threshold value e _TH Control corresponding to the output request signal (that is, control for maintaining the value of the target physical quantity at the value VAL ₁ ) is executed, and the change corresponding control is performed from the time when the absolute value | e | becomes larger than the threshold value e _TH. Run. That is, when there is a request to change the output to the three-phase load 3 in a section where the power supply voltage e (specifically, its absolute value) is equal to or less than the threshold value e _TH , the DSP 12 performs control according to the change request. Is delayed until the end of the first interval. When execution of the change control is started, p _out changes in response to changes in v _uv ^* , v _vw ^*, and v _wu ^* , and i _rb ^* , I _sb ^*, and v _st ^* depend on p _out ^. Also changes. At this time, as described above, the correction value Δi _r ^* corresponding to the capacitor voltage error is generated, and the command value i _r ^* is generated through the correction by Δi _r ^* . As a result, the imbalance between the input and output power of the switching circuit 7 that can occur when the output request changes, and the output waveform distortion of the switching circuit 7 associated therewith can be reduced.

  The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims. The above embodiment is merely an example of the embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the above embodiment. The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values.

DESCRIPTION OF SYMBOLS 1 Single-phase / three-phase matrix converter system 2 Single-phase alternating current power supply 3 Three-phase load 4 Single-phase / three-phase matrix converter apparatus 5 Filter circuit 6 Power ripple compensation capacitor 7 Switching circuit 8 Voltage detection part 9 Current detection part 10 Control part 50 Input Current Command Value Calculation Block 51 Reference Command Calculation Unit 52 to 54 Calculation Units LN _r , LN _s , LN _t Input Line LN _u , LN _v , LN _w Output Line

Claims (9)

A capacitor section for compensating for the pulsation of the instantaneous power of the single-phase AC output from the single-phase AC power supply;
A switching unit that converts single-phase AC power from the single-phase AC power source into three-phase AC power while performing the compensation using the generated power of the capacitor unit;
A control unit for controlling the switching unit,
When the pulsating component of the single-phase AC power includes a non-compensation component that is not compensated for by the generated power of the capacitor unit, the control unit switches from the single-phase AC power source to the switching unit according to the non-compensation component. A single-phase / three-phase converter characterized by correcting input power. The single-phase / three-phase conversion device according to claim 1, wherein the control unit prohibits the correction of the input power when an output voltage of the single-phase AC power supply is equal to or lower than a predetermined value. The controller is
By controlling the switching unit according to a request for output to a load connected to the switching unit, the three-phase AC power according to the request is output from the switching unit,
In a section in which the output voltage of the single-phase AC power supply is equal to or less than a predetermined value, when there is a request for an output change to the load, the execution timing of the control according to the request for the output change is delayed to the outside of the section. The single-phase / three-phase conversion device according to claim 1 or 2, wherein the single-phase / three-phase conversion device is characterized. The control unit obtains a differential power between the input instantaneous power supplied from the single-phase AC power source and the capacitor unit to the switching unit and the output instantaneous power of the switching unit as the non-compensation component, and the differential power 4. The single-phase / three-phase converter according to claim 1, wherein the input power from the single-phase AC power supply to the switching unit is corrected so as to decrease. The controller is
Based on the output power of the switching unit and the output voltage of the single-phase AC power source, a reference command value for the output current of the single-phase AC power source, a reference command value for the output current of the capacitor unit, and a command for the output voltage of the capacitor unit A first computing unit for deriving a value;
Based on the command value for the output voltage of the capacitor unit and the actual output voltage of the capacitor unit, the command value for the output current of the capacitor unit is derived through a process of correcting the reference command value for the output current of the capacitor unit. A second computing unit that
Based on the output voltage of the single-phase AC power source, the actual output voltage of the capacitor unit, the command value for the output current of the capacitor unit, and the reference command value for the output current of the single-phase AC power source, the input instantaneous power is obtained. A third calculation unit for deriving the differential power from the input instantaneous power and the output instantaneous power;
A fourth calculation unit for deriving a command value for the output current of the single-phase AC power supply by correcting a reference command value for the output current of the single-phase AC power supply so that the differential power is reduced;
The single-phase / three-phase converter according to claim 4, wherein input power from the single-phase AC power supply to the switching unit is corrected by correction of the fourth calculation unit. Further comprising first to third input lines interposed between the switching unit and the single-phase AC power source and the capacitor unit;
A single-phase AC voltage from the single-phase AC power source is applied between the first and third input lines,
The capacitor unit is connected between the second and third input lines and absorbs a pulsating component of the single-phase AC power through the switching unit,
The said switching part produces | generates the said three-phase alternating current power based on the electric power input from the said single phase alternating current power supply and the said capacitor | condenser part via the said 1st-3rd input line. Item 6. The single-phase / three-phase converter according to any one of Items 5 to 6. A capacitor unit for compensating for pulsation of instantaneous power of a single-phase AC output from a single-phase AC power source, and a single-phase AC from the single-phase AC power source while performing the compensation using the generated power of the capacitor unit A switching unit that converts electric power into three-phase AC power, and a control method for a single-phase / three-phase converter,
When the pulsating component of the single-phase AC power includes a non-compensation component that is not compensated by the generated power of the capacitor unit, the input power from the single-phase AC power source to the switching unit is corrected according to the non-compensation component A control method for a single-phase / three-phase conversion device. 8. The method for controlling a single-phase / three-phase converter according to claim 7, wherein correction of the input power is prohibited when an output voltage of the single-phase AC power supply is a predetermined value or less. By controlling the switching unit according to a request for output to a load connected to the switching unit, the three-phase AC power according to the request is output from the switching unit,
In a section in which the output voltage of the single-phase AC power supply is equal to or less than a predetermined value, when there is a request for an output change to the load, the execution timing of the control according to the request for the output change is delayed to the outside of the section. The method for controlling a single-phase / three-phase conversion device according to claim 7 or 8, characterized by the above.

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