JP2014090619A - Inverter controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter controller including a small capacity capacitor capable of optimizing the efficiency of a motor drive system by controlling a regenerative energy from a motor utilizing the motor with an increased reluctance torque ratio.SOLUTION: The inverter controller including a small capacity capacitor 32 has drive control means 6 including a current phase difference adjustment section 14 that adjusts a phase difference of the current with respect to an induced voltage generated by the motor 5. The current phase difference adjustment means performs phase adjustment so that the voltage output from orthogonal transforming means 4 is a predetermined set value or less, and at least one of the values of an average value of a torque command value or a current command value given to the motor 5, an average value of effective values of armature currents detected by current detection means 7 and an average peak values of the armature current is a minimum value.

Description

  The present invention is an inverter control device in which smoothing means composed of a capacitor having a remarkably small capacity is connected to the output terminal of the rectifying means, and the output voltage pulsates greatly at twice the frequency of the AC power supply frequency, and in particular, brushless DC The present invention relates to an inverter control device that drives an electric motor such as a motor at an arbitrary rotational speed.

  In general, an inverter control device that drives an electric motor rectifies an AC power source, smoothes the rectified DC power with a smoothing capacitor, converts the smoothed DC power into AC power with an arbitrary rotation speed and voltage, AC power is supplied to the motor. In such a configuration, since a smoothing capacitor is essential, the smoothing capacitor has been a factor in increasing the size and cost. However, if the smoothing capacitor is unnecessary or has a significantly reduced capacity, pulsation synchronized with the AC power supply will occur in the rectified DC voltage, which will adversely affect the motor, such as increased torque pulsation and reduced drive efficiency. It has been known.

  Therefore, in order to reduce the adverse effect on the motor due to the pulsation of the DC voltage when this smoothing capacitor is unnecessary or greatly reduced in capacity, the inverter output voltage corresponding to the voltage command value given to the motor is saturated. There is a method of advancing the phase of the inverter output voltage by advancing the output timing of the PWM signal (see, for example, Patent Document 1).

  In the method of Patent Document 1, when the DC voltage applied to the inverter decreases due to pulsation, the applied voltage of the electric motor is limited by weakening the field magnetic flux of the electric motor (corresponding to so-called field weakening control). . However, in this method, it is necessary to flow an armature current for weakening the field magnetic flux of the electric motor, and there are concerns about adverse effects such as an increase in the armature current and a decrease in driving efficiency of the electric motor.

  For this reason, in an inverter control device having a configuration in which a smoothing capacitor is unnecessary or has a significantly reduced capacity, when the applied voltage of the motor is limited, the field control is performed by controlling the current so that the total magnetic flux of the motor is kept constant. There is a method in which the operation is naturally performed and the reduction in the drive efficiency of the motor is reduced by minimizing the armature current of the motor (see, for example, (0052) to (0077) of Patent Document 2).

  In the method of Patent Document 2, the total magnetic flux of the motor (generated from the stator side) is integrated by integrating the voltage difference between the applied voltage of the motor and the voltage drop (winding resistance value × current value) due to the winding resistance of the motor. The amount of the magnetic flux and the magnetic flux generated from the rotor side is calculated, proportional integral control is performed based on the magnetic flux difference between the magnetic flux command and the total magnetic flux calculation value, and the total magnetic flux calculation value is a constant value (magnetic flux) Command), the current of the component (orthogonal two-axis coordinate system) acting on the field-weakening operation is controlled in accordance with the change in the applied voltage of the electric motor.

  In addition, in order to increase the effect of field weakening control in the high-speed rotation region, it is described that the magnetic flux command is reduced as the rotation speed of the electric motor is increased, and accordingly, the total amount of magnetic flux to be kept constant is reduced.

In addition, the inverter control device disclosed in Patent Document 2 also describes measures against a phenomenon in which the harmonic component of the input current increases due to the occurrence of a non-current period in the input current from the AC power supply due to regenerative energy from the motor. This is achieved by reducing the current command value of the component (orthogonal two-axis coordinate system) that acts on the field-weakening operation in the phase corresponding to the zero cross point of the AC power supply voltage, and near the zero cross of the AC power supply voltage. In the method of suppressing the current in the regenerative operation direction and the motor with specifications that reduce the influence of the induced voltage generated by the field magnet and increase the ratio of reluctance torque in the embedded magnet field type synchronous motor (IPM motor) There are methods to be used, and in each case, the effect of suppressing the harmonic component of the input current by reducing the regenerative energy is presented.

  Furthermore, as another method for minimizing the reduction in the drive efficiency of the motor by minimizing the armature current of the motor, the same torque as the current command value of “field weakening control” obtained from the limit value of the applied voltage of the motor is used. Induced voltage of the motor calculated from each current command value with the current command value of `` maximum torque control '' obtained with a current phase that minimizes the amplitude of the armature current of the motor in the generated current vector By comparing the current command value (either field weakening control or maximum torque control) with a smaller induced voltage and controlling the current, it is possible to reduce the drive efficiency of the motor while realizing stable driving of the motor. There is also a method of mitigating (see, for example, Non-Patent Document 1).

JP-A-10-150795 Japanese Patent No. 4663904

Tatsuya Nishihara, Shigeo Morimoto, Masayuki Sanada: “Effects of eliminating electrolytic capacitors in the IPMSM speed control system” 2009 Annual Conference of the Institute of Electrical Engineers of Japan, 4-067, p. 116-117 (4th volume)

  However, the inverter control device having the above-described conventional configuration minimizes the armature current of the motor by minimizing the field-weakening operation, reduces the driving efficiency of the motor, or reduces the regenerative operation direction. By using a motor with specifications that control the current and reduce the effect of the induced voltage generated by the field magnet and increase the ratio of reluctance torque, the regenerative energy from the motor is reduced and the input current from the AC power supply is reduced. The harmonic component is suppressed, and the entire system efficiency of the motor drive system (inverter control device including the motor) cannot be optimized.

  The present invention solves the above-described conventional problems, and in an inverter control device configured with a small-capacitance capacitor, an electric motor using a motor with an increased reluctance torque ratio and controlling regenerative energy from the motor. The purpose is to optimize the overall efficiency of the drive system.

In order to solve the above-described conventional problems, the inverter control device of the present invention generates a magnet torque generated along with a field magnetic flux and an armature current, an inductance change of the armature winding, and an armature current. An inverter control device that drives a motor that uses a reluctance torque in combination and increases the ratio of the reluctance torque,
Rectifying means with an AC power supply as input, smoothing means in which the value of the capacitor is set so that the output voltage of the rectifying means pulsates at approximately twice the frequency of the AC power supply frequency, and the smoothing voltage from the smoothing means for driving the motor An orthogonal transformation means for converting to a desired alternating voltage, a drive control means for transmitting information for driving the motor corresponding to the smooth voltage to the orthogonal transformation means, and a current detection means for detecting the armature current of the motor ,
The drive control means includes a current phase difference adjusting means for adjusting a current phase difference with respect to the induced voltage generated by the electric motor, and a torque command to be given to the electric motor by which the voltage output from the orthogonal transformation means is equal to or lower than a preset voltage set value. So that at least one of the average value of the current value or the current command value, the average value of the effective value of the armature current detected from the current detection means, or the average value of the peak value of the armature current is the minimum value. The phase adjustment is performed by the current phase difference adjusting means.

  As a result, the regenerative energy from the motor is controlled to a predetermined value or less to optimize the efficiency of the "converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)" and to minimize the armature current of the motor. By doing so, the reduction in the motor efficiency can be reduced and the efficiency of the entire system can be optimized.

In addition, the inverter control device of the present invention uses both the magnet torque generated with the field magnetic flux and the armature current and the reluctance torque generated with the inductance change of the armature winding and the armature current. And an inverter control device for driving an electric motor having a high reluctance torque ratio,
Rectifying means with an AC power supply as input, smoothing means in which the value of the capacitor is set so that the output voltage of the rectifying means pulsates at a frequency approximately twice the AC power supply frequency, and the smoothing voltage from the smoothing means for driving the motor An orthogonal transformation means for converting to a desired alternating voltage, a drive control means for transmitting information for driving the motor corresponding to the smooth voltage to the orthogonal transformation means, and a current detection means for detecting the armature current of the motor ,
The drive control means includes a current phase difference adjusting means for adjusting a phase difference of the armature current with respect to the induced voltage generated by the electric motor, and a regeneration period measuring means for measuring a period during which the regenerative current flows from the electric motor to the capacitor. Torque command value or current applied to the motor when the voltage output by the orthogonal transformation means is equal to or less than a preset voltage set value and the regeneration period measurement value measured by the regeneration period measurement means is equal to or less than a preset regeneration period set value. The current phase difference so that at least one of the average value of the command values, the average value of the effective value of the armature current detected from the current detection means, and the average value of the peak value of the armature current is the minimum value. The adjustment means adjusts the phase.

  As a result, the period during which the regenerative energy and regenerative current from the motor are flowing is controlled to a predetermined value or less, and the non-flow period of the input current from the AC power source is reliably suppressed to a predetermined value or less, while the “converter (rectifier Means + smoothing means) + inverter (orthogonal transformation means) "to reduce the motor efficiency by minimizing the armature current of the motor and optimize the efficiency of the entire system Can do.

  The inverter control device of the present invention can optimize the overall system efficiency of the electric motor drive system by utilizing an electric motor with a high reluctance torque ratio and controlling the regenerative energy from the electric motor.

The system block diagram of the inverter control apparatus in the 1st Embodiment of this invention The system block diagram of the inverter control apparatus in the 2nd Embodiment of this invention The system block diagram of the inverter control apparatus in the 3rd Embodiment of this invention The figure which shows an example of the time change of the phase current state of an electric motor The figure which shows an example of the change of a PWM signal The figure which shows the state of the electric current which flows into an electric motor and an orthogonal transformation means at the time of the drive by the PWM signal in FIG. The figure which shows an example of the change of a PWM signal The figure which shows the state of the electric current which flows into an electric motor and an orthogonal transformation means at the time of the drive by the PWM signal in FIG. First operation characteristic diagram of the inverter control device of the present invention Second operational characteristic diagram of inverter control device of the present invention One characteristic diagram of the total amount of regenerative energy and motor applied voltage in the inverter control device of the present invention One characteristic diagram of the total amount of regenerative energy and the converter (rectifier means + smoothing means), inverter (orthogonal transform means), converter (rectifier means + smoothing means) + inverter (orthogonal transform means) efficiency in the inverter control device of the present invention One characteristic diagram of the motor output torque in the inverter control device of the present invention Schematic of the first processing flow in the inverter control device of the present invention Schematic of the second processing flow in the inverter control device of the present invention. One characteristic diagram of current phase difference and armature current in the inverter control device of the present invention

The first invention uses both the magnet torque generated with the field magnetic flux and the armature current, and the reluctance torque generated with the inductance change of the armature winding and the armature current, and the reluctance thereof. An inverter control device for driving an electric motor with a high torque ratio,
Rectifying means with an AC power supply as input, smoothing means in which the value of the capacitor is set so that the output voltage of the rectifying means pulsates at approximately twice the frequency of the AC power supply frequency, and the smoothing voltage from the smoothing means for driving the motor An orthogonal transformation means for converting to a desired alternating voltage, a drive control means for transmitting information for driving the motor corresponding to the smooth voltage to the orthogonal transformation means, and a current detection means for detecting the armature current of the motor ,
The drive control means includes a current phase difference adjusting means for adjusting a current phase difference with respect to the induced voltage generated by the electric motor, and a torque command to be given to the electric motor by which the voltage output from the orthogonal transformation means is equal to or lower than a preset voltage set value. So that at least one of the average value of the current value or the current command value, the average value of the effective value of the armature current detected from the current detection means, or the average value of the peak value of the armature current is the minimum value. It is characterized in that it is configured to perform phase adjustment with current phase difference adjustment means,
By controlling the regenerative energy from the motor below a predetermined value, the efficiency of the "converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)" is optimized, and the armature current of the motor is minimized. Thus, the reduction in motor efficiency can be reduced and the efficiency of the entire system can be optimized.

According to a second aspect of the present invention, the reluctance is obtained by using both the magnet torque generated with the field magnetic flux and the armature current and the reluctance torque generated with the inductance change of the armature winding and the armature current. An inverter control device for driving an electric motor with a high torque ratio,
Rectifying means with an AC power supply as input, smoothing means in which the value of the capacitor is set so that the output voltage of the rectifying means pulsates at approximately twice the frequency of the AC power supply frequency, and the smoothing voltage from the smoothing means for driving the motor An orthogonal transformation means for converting to a desired alternating voltage, a drive control means for transmitting information for driving the motor corresponding to the smooth voltage to the orthogonal transformation means, and a current detection means for detecting the armature current of the motor ,
The drive control means includes a current phase difference adjusting means for adjusting a phase difference of the armature current with respect to the induced voltage generated by the electric motor, and a regeneration period measuring means for measuring a period during which the regenerative current flows from the electric motor to the capacitor. The voltage output by the orthogonal transform means is equal to or less than a preset voltage set value, and the regeneration period measurement value measured by the regeneration period measurement means is equal to or less than a preset regeneration period set value, and a torque command value applied to the motor or The current level is such that at least one of the average value of the current command value, the average value of the effective value of the armature current detected from the current detection means, and the average value of the peak value of the armature current is the minimum value. It is characterized in that it is configured to perform phase adjustment with phase difference adjusting means,
By controlling the period during which regenerative energy and regenerative current from the motor are flowing to each of a predetermined value or less, the non-current conduction period of the input current from the AC power supply is reliably suppressed to a predetermined value or less, and the “converter (rectifier + Smoothing means) + inverter (orthogonal transformation means) ", the reduction of the motor efficiency can be reduced by minimizing the armature current of the motor, and the efficiency of the entire system can be optimized. .

According to a third aspect of the invention, particularly in the inverter control device of the second aspect of the invention, the AC voltage detection means for detecting the voltage of the AC power supply and the absolute value taking the absolute value of the AC voltage detection value detected by the AC voltage detection means Conversion means and smoothing voltage detection means for detecting the smoothing voltage,
The regenerative period measuring means flows a regenerative current from the motor to the capacitor based on the magnitude relationship between the absolute value of the AC voltage detected value converted by the absolute value converting means and the smoothed voltage detected value detected by the smoothed voltage detecting means. It is characterized by being configured to measure the period of time,
Even when the voltage distortion of the AC power supply or the power supply frequency fluctuates, it is possible to reliably measure the period during which the regenerative current flows from the motor to the capacitor.

In the fourth aspect of the invention, particularly in the inverter control device of the second aspect of the invention, the current detecting means directly detects the bus current on the DC side of the orthogonal transform means, and the electric current flows indirectly to the motor from the detected value of the bus current. A configuration for detecting a child current,
The regeneration period measuring means is characterized in that it is configured to measure the period during which the regeneration current flows from the motor to the capacitor based on the detected value of the bus current.
Since it can be used together with the detection of the armature current flowing through the motor, it is not necessary to provide a new sensor or the like, which is advantageous in terms of cost.

According to a fifth aspect of the invention, in particular, in the inverter control device according to any one of the first, second and fourth aspects, the apparatus further comprises a smoothing voltage detecting means for detecting a smoothing voltage,
It is characterized in that the phase adjustment is performed by the current phase difference adjusting means only when the smoothed voltage detection value detected by the smoothing voltage detecting means is less than an arbitrary set value.
The processing time of the microcomputer, system LSI, etc. can be shortened.

According to a sixth aspect of the invention, in particular, in the inverter control device according to any one of the first, second, and fourth aspects, the AC voltage detecting means for detecting the voltage of the AC power source and the AC voltage detected by the AC voltage detecting means An absolute value converting means for taking the absolute value of the detected value;
Only when the absolute value of the AC voltage detection value converted by the absolute value conversion means is less than an arbitrary set value, the current phase difference adjustment means is configured to perform phase adjustment,
The processing time of the microcomputer, system LSI, etc. can be shortened.

  According to a seventh aspect of the invention, in particular, in the inverter control device of the third aspect of the invention, at least one of a smoothed voltage detection value detected by the smoothing voltage detection means and an absolute value of the alternating voltage detection value converted by the absolute value conversion means The phase adjustment is performed by the current phase difference adjustment means only when one value is less than an arbitrary set value, and the processing time of the microcomputer, the system LSI, etc. can be shortened. it can.

  In the eighth aspect of the invention, in particular, in the inverter control device according to any one of the first to seventh aspects of the invention, the smoothing means includes a capacitor and a reactor, and the resonance frequency required by the capacitor and the reactor is set to the AC power supply frequency. It is characterized in that it is set to be 40 times or more, and it is possible to realize high performance of the power supply harmonic characteristics in the input current from the AC power supply.

  According to a ninth aspect of the invention, in the inverter control device according to any one of the first to eighth aspects of the invention, the voltage setting value is the applied voltage of 2. when the regenerative energy charged from the motor to the capacitor is zero. It is set to be 5 times or less, and the efficiency of "converter (rectifier means + smoothing means) + inverter (orthogonal transformation means)" is optimized by reliably controlling the regenerative energy from the motor below a predetermined value. Can be planned.

  According to a tenth aspect of the invention, in particular, in the inverter control device according to any one of the first to ninth aspects, the applied voltage of the electric motor controlled by the drive control means at a predetermined rotational speed and load torque is from the electric motor to the capacitor. The specification of the electric motor is determined so that it is 2.5 times or less of the applied voltage when the regenerative energy charged to zero is zero, and the regenerative energy from the electric motor is surely suppressed to a predetermined value or less. Efficiency optimization of “converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)” can be achieved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments. (Embodiment 1)
FIG. 1 shows a system configuration diagram of an inverter control device according to a first embodiment of the present invention. This inverter control device is supplied with power from an AC power source 1 such as a commercial power source that is a single-phase AC power source, and a rectifying unit 2 composed of a diode bridge for full-wave rectifying the supplied AC power source 1, and a rectifying unit 2 The smoothing means 3 in which the value of the capacitor 32 is set so that the output voltage from the pulsation greatly pulsates at approximately twice the frequency of the AC power supply frequency, and the smoothing voltage from the smoothing means 3 is converted into an AC voltage having a desired frequency and voltage value. The orthogonal transformation means 4 and the drive control means 6 which transmit the information for performing the motor drive corresponding to a smooth voltage to the orthogonal transformation means 4 are provided.

  The electric motor 5 includes a stator 51 to which three armature windings (51u, 51v, 51w) Y-connected around a neutral point are attached, and a rotor 52 to which a magnet is attached. The electric motor 5 includes a magnetic torque generated by a field magnetic flux generated by a magnet of the rotor 52 and an armature current (51u, 51v, 51w) of the stator 51, and an armature winding (51u). , 51v, 51w) and the reluctance torque generated in association with the inductance change and the armature current are used together to increase the ratio of the reluctance torque.

  The orthogonal transforming means 4 includes half-phase circuits composed of a pair of switching elements for U-phase, V-phase, and W-phase. The pair of switching elements of the half-bridge circuit are connected in series between the high-voltage side end and the low-voltage side end of the capacitor 32, and a smoothing voltage across the capacitor 32 is applied to the half-bridge circuit. The U-phase half-bridge circuit includes a high-voltage side switching element 41u and a low-voltage side switching element 41x. The V-phase half-bridge circuit includes a switching element 41v on the high voltage side and a switching element 41y on the low voltage side. The W-phase half-bridge circuit includes a switching element 41w on the high voltage side and a switching element 41z on the low voltage side. In addition, a free-wheeling diode (42u to 42z) is connected in parallel with each switching element.

  The smoothing voltage applied to the orthogonal transformation means 4 is converted into a three-phase AC voltage by the switching operation of the switching element in the orthogonal transformation means 4 described above, and the electric motor 5 is thereby driven. Further, a current detecting means 7 for detecting a bus current is arranged on the DC side bus of the orthogonal transform means 4.

  The smoothing means 3 includes a reactor 31 that is set so that the LC resonance frequency is 40 times or more the AC power supply frequency, and reduces the peak value of the inrush charging / discharging current to the small-capacitance capacitor 32.

The drive control means 6 can be configured by a microcomputer, a system LSI or the like, and includes a base driver 11, a PWM signal generation unit 12, a current control unit 13, a current phase difference adjustment unit 14, a phase current conversion unit 15, a rotor position. Each functional block includes a speed estimation unit 16, an applied voltage calculation unit 17, and a current calculation unit 20.

  The phase current conversion unit 15 observes the bus current on the DC side of the orthogonal transform unit 4 flowing in the current detection unit 7 and converts the bus current into an armature current of the motor 5. The phase current converter 15 actually detects the current only for a predetermined period from when the DC bus current of the orthogonal transform means 4 is converted.

  The rotor position speed estimator 16 includes an armature current of the electric motor 5 converted by the phase current converter 15, an output voltage calculated by the PWM signal generator 12, and a smooth voltage detected by the smooth voltage detector 8. The rotor magnetic pole position and rotation speed of the electric motor 5 are estimated based on the above information.

  In the current control unit 13, deviation information between the current phase difference given from the current phase difference adjusting unit 14, the rotation speed of the motor 5 estimated by the rotor position speed estimation unit 16, and the speed command value given from the outside is included. Based on this, the current command value is derived using PI calculation or the like so that the rotation speed of the electric motor 5 matches the speed command value.

  The PWM signal generation unit 12 includes a current command value derived by the current control unit 13, an armature current of the electric motor 5 converted by the phase current conversion unit 15, and the electric motor 5 estimated by the rotor position speed estimation unit 16. A PWM signal for driving the electric motor 5 is generated based on the rotor magnetic pole position information.

  The generation of the PWM signal in the PWM signal generation unit 12 is performed when, for example, the smoothing voltage applied to the orthogonal transformation means 4 is 200 V, the U-phase instruction voltage is 150 V, the V-phase instruction voltage is 100 V, and the W-phase instruction voltage. Is 0 V, the duty ratio of the PWM signal of each phase (time ratio of the state in which the upper arm switching element is on in the carrier period of the PWM signal) is 75% for the U phase, 50% for the V phase, and W phase. Becomes 0%.

  That is, the result of dividing the command voltage of each phase by the smooth voltage is the duty of the PWM signal. Moreover, when the instruction voltage of each phase exceeds the smoothing voltage, the duty of the PWM signal is 100%.

  The PWM signal obtained as described above is finally output to the base driver 11, and each switching element (41u to 41z) is driven according to the PWM signal to generate a sinusoidal alternating current. As described above, in this embodiment, the sine wave drive of the electric motor 5 is realized by flowing a sine wave armature current.

  Next, the manner in which the armature current of the motor 5 appears in the bus current flowing in the DC side bus of the orthogonal transform means 4 will be described with reference to FIGS.

  FIG. 4 is a diagram showing the state of the armature current flowing in the armature winding of the electric motor 5 and the direction of the current flowing in the armature winding of each phase in each section of the electrical angle every 60 °.

  Referring to FIG. 4, in the section where the electrical angle is 0 to 60 °, the U-phase winding 51u and the W-phase winding 51w are neutral from the unconnected end to the neutral point, and the V-phase winding 51v is neutral. Current flows from the point toward the unconnected end. Further, in the section of electrical angle 60 to 120 °, the U-phase winding 51u is directed from the non-connection end toward the neutral point, and the V-phase winding 51v and the W-phase winding 51w are not connected from the neutral point. Current is flowing toward the edge. Hereinafter, it is shown that the state of the phase current flowing through the windings of each phase changes every electrical angle of 60 °.

  For example, let us consider a case where the PWM signal corresponding to the half carrier period generated by the PWM signal generation unit 12 when the electrical angle is 30 ° in FIG. 4 changes as shown in FIG. Here, in FIG. 5, the signal U is the switching element 41u, the signal V is the switching element 41v, the signal W is the switching element 41w, the signal X is the switching element 41x, the signal Y is the switching element 41y, and the signal Z is The signal which operates switching element 41z is shown. These signals are listed as active high. In this case, as shown in FIG. 6, the current on the DC side bus of the orthogonal transform means 4 does not appear at the timing 1, and the armature current (W-phase current) flowing through the W-phase winding 51 w appears at the timing 2, At timing 3, an armature current (V-phase current) flowing through the V-phase winding 51v appears.

  As another example, let us consider a case where the PWM signal of the half carrier period generated by the PWM signal generation unit 12 when the electrical angle is 30 ° in FIG. 4 changes as shown in FIG. In this case, as shown in FIG. 8, the current does not appear at the timing 1 and the armature current (U-phase current) flowing through the U-phase winding 51u appears at the timing 2 on the DC-side bus of the orthogonal transforming means 4, At timing 3, an armature current (W-phase current) flowing in the W-phase winding 51w appears. Here, the bus current on the DC side of the orthogonal transformation means 4 at the timing 3 is a direction that flows from the low voltage side end of the capacitor 32 to the high voltage side end of the capacitor 32 via the orthogonal transformation means 4 and is generated in the electric motor 5. The regenerative state is shown in which the regenerated electrical energy is returned to the capacitor 32 (hereinafter, this electrical energy is referred to as regenerative energy).

  Thus, it can be seen that the phase current of the electric motor 5 corresponding to the state of the switching elements (41u to 41z) appears on the bus of the orthogonal transform means 4.

  Specifically, when any one of the upper arm switching elements (41u, 41v, 41w) is turned on, the armature current of the turned-on phase or the lower arm switching elements (41x, 41y, 41z) has a relationship in which the armature current of the turned-on phase appears on the bus of the orthogonal transform means 4 when any one of them is turned on.

  If the current for two phases can be determined at close timings within the carrier period as described above, it is clear that the armature current (iu, iv, iw) of each phase is obtained from the relationship of the following equation. .

iu + iv + iw = 0 (1)
Timing 4 and timing 5 are dead time periods for preventing the upper and lower arms of the orthogonal transform means 4 from being short-circuited due to the operation delay of the switching elements (41u to 41z). The bus current is indefinite depending on the direction in which the armature current of each phase flows.

  FIG. 9 is a first operational characteristic diagram of the inverter control device of the present invention, in which the AC voltage absolute value of the AC power supply 1 (broken line portion in FIG. 9A) and the smoothing voltage applied to the orthogonal transform means 4 are shown. (Solid line part of FIG. 9A) and the waveform of the bus current (FIG. 9B) on the DC side of the orthogonal transforming means 4 flowing in the current detecting means 7 are shown.

  Since the capacity of the capacitor 32 in the inverter control device of the present invention is extremely small, the smoothing voltage applied to the orthogonal transformation means 4 when a current flows through the motor 5 is approximately 2 of the power supply frequency fs of the AC power supply 1. Pulsates greatly at double frequency.

The waveform of the bus current on the DC side of the orthogonal transformation means 4 flowing in the current detection means 7 is orthogonal to the direction from the orthogonal transformation means 4 to the low voltage side end of the capacitor 32 and conversely from the low voltage side end of the capacitor 32. The flow direction to the means 4 is shown as negative, and has a pulse-like waveform according to the operation of each switching element (41u to 41z) in the orthogonal transform means 4.

  In the inverter control device constituted by the small-capacitance capacitor 32, the period during which the bus current on the DC side of the orthogonal transform means 4 is negative as shown in FIG. The regenerative energy from the electric motor 5 is charged in the capacitor 32 during this regeneration period.

  The total amount Ereg of regenerative energy charged in the capacitor 32 can be obtained by integrating the difference between the smoothing voltage Vdc applied to the orthogonal transformation means 4 and the AC voltage absolute value | Vac | This corresponds to the shaded area in FIG.

Ereg = ∫ (Vdc− | Vac |) dt (2)
The total amount of regenerative energy Ereg is not limited to the AC voltage value of the AC power source 1, the capacity of the reactor 31 and the capacitor 32 of the smoothing means 3, and the specifications of the motor 5 and the load conditions (rotation speed, load torque, environmental temperature, etc.). In particular, attention is paid to an applied voltage (including an induced voltage generated by the electric motor 5) necessary for driving the electric motor 5.

  FIG. 11 is a graph showing the characteristics of the regenerative energy total amount Ereg and the applied voltage of the motor 5 controlled by the drive control means 6 under two different load conditions (A, B). The applied voltage of the motor 5 is large. There is a monotonically increasing relationship in which the total amount of regenerative energy Ereg increases.

  FIG. 12 is a graph showing the characteristics of the total amount of regenerative energy Ereg, the converter (rectifying means 2 + smoothing means 3), and the efficiency of the inverter (orthogonal transformation means 4). If the total amount of regenerative energy Ereg becomes excessive, “converter (rectifying means) Since the total efficiency of “2 + smoothing means 3) + inverter (orthogonal transformation means 4)” decreases, the inverter control device of the present invention achieves the minimum efficiency (predetermined efficiency target value) to achieve the total efficiency, and the total amount of regenerative energy A limit value is provided for Ereg, and the total amount of regenerative energy Ereg from the electric motor 5 is controlled to be equal to or less than the limit value.

  An example of the operation when the total amount of regenerative energy Ereg is controlled below the limit value will be described with reference to FIG. FIG. 10 is a second operational characteristic diagram of the inverter control device of the present invention. Similar to FIG. 9, the AC voltage absolute value of the AC power supply 1 (broken line portion in FIG. 10A) and the orthogonal transform means 4 The waveform of the applied smoothing voltage (solid line part in FIG. 10A) and the bus current on the DC side of the orthogonal transforming means 4 flowing in the current detecting means 7 (FIG. 10B) is shown. In FIG. 10, not only the total regenerative energy amount Ereg but also the regenerative period is reduced, and as a result, the reactive power caused by the regenerative energy charged from the electric motor 5 to the capacitor 32 can be reduced.

  Based on the monotonically increasing relationship of FIG. 11, an applied voltage setting value of the motor 5 corresponding to the limit value of the total regenerative energy Ereg is provided, and the applied voltage (line voltage) of the motor 5 is determined from the voltage value output by the orthogonal transformation means 4. A method of detecting the total amount of regenerative energy Ereg indirectly by calculating the average value of the effective values is employed.

  However, as shown in FIG. 11, since the applied voltage of the electric motor 5 also depends on the load conditions (rotation speed, load torque, environmental temperature, etc.), for example, based on the actual machine test results, simulation analysis results, etc. A plurality of applied voltage setting values are provided as table data for each table (in FIG. 11, respective applied voltage setting values (VAset, VBset) are provided for two different load conditions (A, B)).

The applied voltage setting value is 2.5 times or less of the applied voltage when the regenerative energy charged from the electric motor 5 to the capacitor 32 is zero based on the actual machine test results and simulation analysis results. It is preferable to set (for example, in the case of the load condition A in FIG. 11, assuming that the applied voltage when the regenerative energy from the motor 5 becomes zero is VA0, the applied voltage set value VAset satisfies the condition of the expression (3). To set).

VAset ≦ 2.5 × VA0 (3)
Therefore, in the inverter control device of the present invention, the applied voltage calculation unit 17 calculates the applied voltage of the electric motor 5, the applied voltage calculated value is equal to or less than the preset applied voltage set value, and the electric motor 5 in the current control unit 13 At least one of an average value of current command values to be applied, an average value of effective values of the armature current converted by the phase current conversion unit 15, and an average value of peak values of the armature current (calculated by the current calculation unit 20). The current phase difference adjustment unit 14 adjusts the phase difference of the current with respect to the induced voltage generated by the electric motor 5 so that the two values are minimized.

  Hereinafter, specific operations of the applied voltage calculation unit 17, the current calculation unit 20, and the current phase difference adjustment unit 14, which are features of the inverter control device of the present invention, will be described with reference to FIG.

  FIG. 14 is a diagram showing an outline of the first processing flow of the inverter control device of the present invention. In the inverter control device of the present invention, the capacitor 32 has a remarkably small capacity, and the armature of the motor 5 is used. Since the current pulsates greatly, prior to calculation of the effective value of the armature current of the motor 5 in the current calculation unit 20 and the applied voltage of the motor 5 in the applied voltage calculation unit 17, the speed command value given from the outside is made constant and the motor 5 is fixed to a predetermined rotation speed (for example, one of the rotation speeds of the table data described above) (S101).

  Next, the current calculation unit 20 calculates the average value Ia of the effective values of the armature current converted by the phase current conversion unit 15 every predetermined time Ta set in advance (S102).

Ia = Σ {√ (id ^ 2 + iq ^ 2) / √ (3) × ΔT} / Ta (4)
Here, id: d-axis current detection value, iq: q-axis current detection value, id ^ 2: id square value, iq ^ 2: iq square value, and armature current is a three-phase AC coordinate system Coordinate conversion is performed from (iu, iv, iw) to the rotating coordinate system (id, iq).

  For the predetermined time Ta, it is preferable to set an integer multiple of the smoothing voltage fluctuation period.

  Next, the applied voltage calculation unit 17 calculates the average value Va of the effective line voltage of the electric motor 5 from the output voltage calculated by the PWM signal generation unit 12 (S103).

Va = Σ {√ (vd ^ 2 + vq ^ 2) × ΔT} / Ta (5)
Here, vd: d-axis output voltage, vq: q-axis output voltage, vd ^ 2: square value of vd, vq ^ 2: square value of vq, and the output voltage is a three-phase AC coordinate system (u, Coordinate conversion is performed from v, w) to the rotating coordinate system (d, q).

  Next, in the current phase difference adjusting unit 14, first, an applied voltage calculated value (line voltage effective value average Va) calculated by the applied voltage calculating unit 17 is set in advance to an applied voltage set value (line voltage set value). It is determined whether or not the applied voltage is less than or equal to (S104). If the applied voltage calculated value exceeds the applied voltage set value, the applied voltage calculated value (line voltage effective value average Va) is the applied voltage set value (line voltage). The current phase difference βT is monotonously increased by a predetermined change width Δβ1 until the current value is equal to or less than the set value), and the field weakening operation is performed (S106). Thus, the total amount Ereg of regenerative energy from the electric motor 5 can be controlled to be equal to or less than a predetermined limit value.

Next, as the operation of the current phase difference adjusting unit 14 after the applied voltage calculation value (line voltage effective value average Va) becomes equal to or less than the applied voltage set value (line voltage set value), the current phase difference βT is set to a predetermined value. Is changed by a change width Δβ2 (which is smaller than Δβ1), and the value of Ia is calculated based on the change in the average value Ia (calculated by the equation (4)) of the effective value of the armature current before and after the change of the current phase difference βT. The current phase difference βT is adjusted so that the value becomes the minimum value (S105).

  Specifically, as shown in FIG. 16, since the average value Ia of the effective values of the armature current with respect to the current phase difference βT changes by a quadratic function having a minimum value, first, the current phase difference βT is changed by the change amount Δβ2. If the change in Ia is decreasing before and after the change of the current phase difference βT, the current phase difference βT is further increased by Δβ2, and conversely, the change in Ia is increasing before and after the change of the current phase difference βT. In this case, the current phase difference βT is decreased by Δβ2, and the current phase difference βT is adjusted so that the change in the value of Ia changes from the decreasing direction to the increasing direction when the current phase difference βT is changed. The value can be a minimum value.

  As described above, the regenerative energy from the electric motor 5 is controlled to a predetermined value or less to optimize the efficiency of the “converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)” (the necessary minimum (predetermined efficiency target) Value)), while reducing the armature current of the motor 5 to a minimum, the reduction in the motor efficiency can be reduced, and the efficiency of the entire system can be optimized.

  In the above description, the current calculation unit 20 calculates the average value Ia of the effective values of the armature current converted by the phase current conversion unit 15, but the armature converted by the phase current conversion unit 15. An average value Ipa of current peak values is calculated, and the current phase difference adjustment unit 14 uses Ipa instead of Ia to adjust the current phase difference βT so that the value of Ipa becomes the minimum value. good.

Ipa = Σ {√ (id ^ 2 + iq ^ 2) × √ (2/3) × ΔT} / Ta
(4a)
Further, as another method, the current calculation unit 20 calculates an average value Ia * of current command values set by the current control unit 13 (corresponding to an average value of effective values of the armature current), and adjusts the current phase difference. In the unit 14, the current phase difference βT may be adjusted by using Ia * instead of Ia so that the value of Ia * becomes the minimum value.

Ia * = Σ {√ (id * ^ 2 + iq * ^ 2) / √ (3) × ΔT} / Ta
(4b)
Here, id *: d-axis current command value, iq *: q-axis current command value, id * ^ 2: id * square value, iq * ^ 2: iq * square value.

  Hereinafter, a specific method for determining the specifications of the small-capacity reactor 31 and the small-capacitance capacitor 32 according to the inverter control device of the present invention will be described.

  In the inverter control device of the present invention, the resonance frequency fLC of the reactor 31 and the capacitor 32 is set to 40 times or more of the power supply frequency fs in order to suppress the harmonic component of the input current from the AC power supply 1 and clear the IEC standard. Thus, the combination of the reactor 31 and the capacitor 32 is determined (so that the constraint condition of fLC ≧ (40 × fs) is satisfied).

  Here, when the capacity of the reactor is L1 [H] and the capacity of the capacitor 32 is C1 [F], the resonance frequency fLC is expressed as follows.

fLC = 1 / {2π × √ (L1 × C1)} (6)
For example, when the power supply frequency is 50 Hz and the capacity of the capacitor 32 is 10 μF, the capacity of the reactor 31 is selected in the range of L1 ≦ 0.633 [mH] based on the above-described constraints and Expression (6).

  Thus, by determining the combination of the small-capacity reactor 31 and the small-capacitance capacitor 32, it is possible to realize high performance of the power supply harmonic characteristics in the input current from the AC power supply 1.

  Hereinafter, a specific method for determining the specifications of the electric motor 5 according to the inverter control device of the present invention will be described.

  The electric motor 5 according to the inverter control device of the present invention includes a magnetic flux generated by the field magnetic flux generated by the magnet of the rotor 52 and the armature current flowing in the armature windings (51u, 51v, 51w) of the stator 51. This is a specification in which the inductance change of the armature windings (51u, 51v, 51w) and the reluctance torque generated along with the armature current are used in combination, and the ratio of the reluctance torque is increased, using FIG. Differences from the conventional motor specifications mainly based on magnet torque will be described.

  FIG. 13 shows the motor output torque (the combined torque of the magnet torque and the reluctance torque) in the motor specification (1) based on the conventional magnet torque and the motor specification (2) in which the ratio of the reluctance torque related to the inverter control device of the present invention is increased. ), And the current phase difference βT when the maximum output torque Tmax is the same and the maximum output torque Tmax is obtained under the same condition of the average value Ia of the effective value of the armature current is the motor specification. The specification of the motor is determined so as to increase from βs1 in (1) to βs2 in the motor specification (2) (the range that βs2 can take is βs1 <βs2 <90 [deg]).

  Further, as described above, the applied voltage calculation unit 17 and the current phase difference adjustment unit 14 indirectly detect the total amount of regenerative energy Ereg from the motor 5 by calculating the applied voltage of the motor 5, and calculate the applied voltage value. Is adjusted so that the total amount of regenerative energy Ereg is less than or equal to the limit value by adjusting the current phase difference βT so that is less than or equal to the preset applied voltage, but the specification of the motor 5 is determined as follows: Thus, it is possible to control so that the total amount of regenerative energy Ereg is less than or equal to the limit value.

  Specifically, at a predetermined rotation speed and load torque, the actual applied voltage (average line voltage effective value) of the motor controlled by the drive control means 6 is zero, and the regenerative energy charged from the motor to the capacitor 32 is zero. The motor specifications are determined so that the applied voltage is 2.5 times or less.

  In this way, by efficiently suppressing the regenerative energy from the electric motor below a predetermined value, the efficiency of the “converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)” is optimized (the necessary minimum (predetermined efficiency) Realization of total efficiency of target value) can be achieved reliably.

(Embodiment 2)
FIG. 2 shows a system configuration diagram of the inverter control device according to the second embodiment of the present invention. The same components as those of the inverter control device (FIG. 1) in the first embodiment are denoted by the same reference numerals, and when the operations are the same, the description is omitted because it is duplicated, and only different contents are described here. To do.

In contrast to the inverter control device (FIG. 1) according to the first embodiment, the inverter control device (FIG. 2) according to the second embodiment uses the orthogonal transform means 4 detected from the current detection means 7 as a component. Is provided with a regenerative period measuring unit 18 for measuring a period during which the regenerative current flows from the electric motor 5 to the capacitor 32 every fluctuation cycle of the smoothing voltage based on the detected DC current on the DC side. In the adjustment unit 14, the application voltage calculation value calculated by the application voltage calculation unit 17 is equal to or less than the preset application voltage set value, and the regeneration period measurement value measured by the regeneration period measurement unit 18 is set in advance. The average value of the current command value given to the motor 5 in the current control unit 13 below the set value, the average value of the effective value of the armature current converted by the phase current conversion unit 15, and the average value of the peak value of the armature current As at least any one value among the calculated) by the current calculation unit 20 is minimized, and adjusts the phase difference between the current with respect to the induced voltage motor 5 is generated.

  Hereinafter, specific operations of the applied voltage calculation unit 17, the current calculation unit 20, the regeneration period measurement unit 18, and the current phase difference adjustment unit 14, which are features of the inverter control device of the present invention, will be described with reference to FIG.

  FIG. 15 is a diagram showing an outline of the second processing flow in the inverter control device of the present invention. Like the inverter control device in the first embodiment, a capacitor 32 having a remarkably small capacity is used. Since the armature current of the motor 5 pulsates greatly, a speed command given from outside prior to the calculation of the effective value of the armature current of the motor 5 in the current calculation unit 20 and the applied voltage of the motor 5 in the applied voltage calculation unit 17. The electric motor 5 is fixed to a predetermined rotation speed (for example, one of the plurality of rotation speeds of the table data) with the value kept constant (S201).

  Next, the regeneration period measuring unit 18 measures a period in which the bus current detection value on the DC side of the orthogonal transform unit 4 detected from the current detection unit 7 is negative at every predetermined time Ta set in advance (S202). .

  Specifically, since the current detection means 7 detects the bus current for each carrier cycle Ts, the bus current detection value is less than a predetermined value (set in view of the influence of ± δ, noise, etc.) by a counter or the like. When the number of times counted is N times during a predetermined time Ta (an integer multiple of the smoothing voltage fluctuation period is set to M times), the regeneration period measurement value Treg for each smoothing voltage fluctuation period is It can be calculated by the following formula.

Treg = N × Ts / M (7)
Thus, since it can be used together with the detection of the armature current flowing through the electric motor 5, it is not necessary to newly provide a sensor or the like, which is advantageous in terms of cost.

  Next, the current calculation unit 20 calculates the average value Ia of the effective values of the armature current converted by the phase current conversion unit 15 by using the formula (4) at every predetermined time Ta set in advance (S203).

  Next, the applied voltage calculation unit 17 calculates the average value Va of the line voltage effective value of the electric motor 5 from the output voltage calculated by the PWM signal generation unit 12 from the equation (5) (S204).

  Next, in the current phase difference adjusting unit 14, first, an applied voltage calculated value (line voltage effective value average Va) calculated by the applied voltage calculating unit 17 is set in advance to an applied voltage set value (line voltage set value). It is determined whether or not it is less than or equal to (S205), and when the applied voltage calculated value exceeds the applied voltage set value, the applied voltage calculated value (line voltage effective value average Va) is the applied voltage set value (line voltage). The current phase difference βT is monotonously increased by a predetermined change width Δβ1 until the current value is equal to or less than the set value), and the field weakening operation is performed (S209). Thus, the total amount Ereg of regenerative energy from the electric motor 5 can be controlled to be equal to or less than a predetermined limit value.

Next, as the operation of the current phase difference adjusting unit 14 after the applied voltage calculated value (line voltage effective value average Va) becomes equal to or less than the applied voltage set value (line voltage set value), first, the regeneration period measuring unit 18 is operated. It is determined whether or not the regenerative period measurement value Treg measured in step S is less than or equal to a preset regenerative period set value (S206). If the regenerative period measurement value Treg exceeds the regenerative period set value, the regenerative period measurement is performed. Until the value Treg becomes equal to or less than the set value for the regeneration period, the current phase difference βT is monotonously increased by a predetermined change width Δβ3 (change width is smaller than Δβ1 and change width is larger than Δβ2) to perform field-weakening operation. The regeneration period is optimized (S208).

  Finally, as an operation of the current phase difference adjustment unit 14 after the regeneration period measurement value Treg becomes equal to or less than the regeneration period set value, the current phase difference βT is changed to a predetermined change width Δβ2 (change width is smaller than Δβ1 and Δβ3). And changing the current phase difference βT so that the value of Ia becomes the minimum value based on the change of the average value Ia (calculated by the equation (4)) of the effective value of the armature current before and after the change of the current phase difference βT. Adjust (S207).

As described above, by controlling the period during which regenerative energy and regenerative current from the electric motor 5 are flowing to a predetermined value or less, the non-flow period of the input current from the AC power supply 1 is reliably suppressed to a predetermined value or less. Optimizing the efficiency of the "converter (rectifying means + smoothing means) + inverter (orthogonal transformation means)" (realizing the total efficiency of the minimum required (preset efficiency target value)) to minimize the armature current of the motor 5 By limiting to the limit, it is possible to reduce the decrease in the motor efficiency and optimize the efficiency of the entire system.
(Embodiment 3)
FIG. 3 shows a system configuration diagram of an inverter control device according to the third embodiment of the present invention. The same components as those of the inverter control device in the first embodiment (FIG. 1) and the inverter control device in the second embodiment (FIG. 2) are denoted by the same reference numerals. Since the description is redundant, it will be omitted, and only different contents will be described here.

  In contrast to the inverter control device of the second embodiment (FIG. 2), in the inverter control device (FIG. 3) of the third embodiment, an AC voltage detection means for detecting the voltage of the AC power source 1 as a component. 9 and an absolute value conversion unit 19 that takes the absolute value of the AC voltage detection value Vac detected by the AC voltage detection means 9 are newly provided. In the regeneration period measurement unit 18, the AC value obtained from the absolute value conversion unit 19 is provided. The period during which the regenerative current flows from the electric motor 5 to the capacitor 32 is measured based on the magnitude relationship between the absolute value | Vac | of the voltage detection value and the smoothing voltage detection value Vdc detected by the smoothing voltage detection means 8. Yes (the AC voltage detection value Vac and the smoothing voltage detection value Vdc are detected at the same frequency, and the timing for detecting them is preferably relatively close).

  Specifically, the detection period of the AC current detection value Vac and the smoothing voltage detection value Vdc is Tsmp, and the regeneration period measurement unit 18 uses a counter or the like to calculate “Vdc> | Vac | ± δ2 (δ2 is in view of the influence of noise or the like). If the number of times counted during a predetermined time Ta (set an integral multiple of the fluctuation period of the smoothing voltage, which is set to M2) is N2 times, the fluctuation of the smoothing voltage is counted. The regeneration period measurement value Treg2 for each cycle can be calculated by the following equation.

Treg2 = N2 × Tsmp / M2 (8)
Since the operation of the other components is the same as that of the inverter control device in the second embodiment, the description thereof is omitted.

  Thus, the period during which the regenerative current flows from the motor 5 to the capacitor 32 is measured based on the magnitude relationship between the absolute value | Vac | of the AC voltage detection value and the smoothed voltage detection value Vdc. Even when the voltage distortion or the power supply frequency fluctuates, it is possible to reliably measure the period during which the regenerative current flows from the motor 5 to the capacitor 32.

  The inverter control devices in the first to third embodiments include the current phase difference given from the current phase difference adjustment unit 14, the rotation speed of the motor 5 estimated by the rotor position speed estimation unit 16, and the external Has been described with the configuration including the current control unit 13 that derives the current command value so that the rotational speed of the electric motor 5 matches the speed command value based on deviation information from the speed command value given from the above, but instead of the current command value A torque control unit for deriving the torque command value Tq * is provided, and in the current phase difference adjustment unit 14, the current phase difference βT is set so that the average value Tqa * of the torque command value Tq * for each predetermined time Ta becomes the minimum value. May be adjusted (for example, the current command value I * is multiplied by the gain K to derive the torque command value Tq * as “Tq * = K × I *”).

  In addition, although the inverter control apparatus in the 1st-3rd embodiment demonstrated by the structure provided with the rotor position speed estimation part 16 which estimates the rotor magnetic pole position and rotation speed of the electric motor 5, an encoder, a resolver, etc. It goes without saying that a position sensor for detecting the magnetic pole position of the rotor may be used.

  In addition, the current detection means of the inverter control apparatus in the first and third embodiments directly detects the bus current on the DC side of the orthogonal transform means 4 and indirectly flows to the motor 5 from the detected value of the bus current. Although the configuration for detecting the armature current has been described, it is needless to say that a current sensor such as DC-CT may be used (in this case, since the armature current can be directly detected, the phase current conversion unit 15 is Is unnecessary).

  In the inverter control devices in the first to third embodiments, the phase adjustment is performed by the current phase difference adjusting unit 14 only when the smoothed voltage detection value detected by the smoothing voltage detecting means 8 is less than an arbitrary set value. By performing the above, it is possible to shorten the processing time of the microcomputer, the system LSI, etc. (an arbitrary set value is the maximum value of the charging voltage of the capacitor 32 by the regenerative energy from the electric motor 5 to the maximum value of the smoothing voltage) Within the range, the AC voltage value of the AC power source 1 and the capacity of the reactor 31 and the capacitor 32 of the smoothing means 3 are set in consideration).

  In the inverter control apparatus according to the third embodiment, the phase adjustment by the current phase difference adjustment unit 14 is performed only when the absolute value of the AC voltage detection value converted by the absolute value conversion unit 19 is less than an arbitrary set value. By performing the above, it is possible to shorten the processing time of the microcomputer, the system LSI, etc. (an arbitrary set value is the maximum value of the charging voltage of the capacitor 32 due to regenerative energy from the motor 5 to the AC voltage detection value) Within the range of the maximum absolute value, the AC voltage value of the AC power source 1, the reactor 31 of the smoothing means 3, the capacity of the capacitor 32, etc. are set.

  As described above, the inverter control device according to the present invention uses an electric motor with a high reluctance torque ratio in an inverter control device configured with a small-capacitance capacitor, and controls the regenerative energy from the electric motor. Since it is possible to optimize the efficiency of the drive system, it can be applied to applications such as driving air conditioners such as air conditioners, refrigerators, and vacuum cleaners.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectification means 3 Smoothing means 31 Reactor 32 Capacitor 4 Orthogonal transformation means 41u-41z Switching element 42u-42z Reflux diode 5 Electric motor 51 Stator 51u-51w Armature winding 52 Rotor 6 Drive control means 7 Current detection means DESCRIPTION OF SYMBOLS 8 Smooth voltage detection means 9 AC voltage detection means 11 Base driver 12 PWM signal generation part 13 Current control part 14 Current phase difference adjustment part 15 Phase current conversion part 16 Rotor position speed estimation part 17 Applied voltage calculation part 18 Regeneration period measurement part 19 Absolute value conversion unit 20 Current calculation unit

Claims (10)

The ratio of the reluctance torque was increased by using both the magnet torque generated along with the field magnetic flux and the armature current and the reluctance torque generated along with the inductance change of the armature winding and the armature current. An inverter control device for driving an electric motor, comprising: rectifying means for receiving an AC power supply; smoothing means for setting a capacitor value so that an output voltage of the rectifying means pulsates at a frequency approximately twice the AC power supply frequency; Orthogonal transformation means for converting the smoothed voltage from the smoothing means to a desired AC voltage for driving the motor, and drive control means for transmitting information for driving the motor corresponding to the smoothed voltage to the orthogonal transformation means And current detection means for detecting an armature current of the motor, wherein the drive control means is for an induced voltage generated by the motor. Current phase difference adjusting means for adjusting the phase difference of the armature current, the voltage output by the orthogonal transform means is equal to or less than a preset voltage set value, and an average value of a torque command value or a current command value applied to the motor The current phase difference adjustment means adjusts at least one of the average value of the effective values of the armature current detected from the current detection means and the average value of the peak values of the armature current to a minimum value. An inverter control device characterized in that it is configured to perform phase adjustment. The ratio of the reluctance torque was increased by using both the magnet torque generated along with the field magnetic flux and the armature current and the reluctance torque generated along with the inductance change of the armature winding and the armature current. An inverter control device for driving an electric motor, wherein the rectifying means receives an AC power supply, and the smoothing means sets the value of the capacitor so that the output voltage of the rectifying means pulsates at a frequency approximately twice the AC power supply frequency; Orthogonal transformation means for converting the smoothed voltage from the smoothing means to a desired AC voltage for driving the motor, and drive control means for transmitting information for driving the motor corresponding to the smoothed voltage to the orthogonal transformation means And current detection means for detecting an armature current of the motor, wherein the drive control means is for an induced voltage generated by the motor. Current phase difference adjusting means for adjusting the phase difference of the armature current, and regeneration period measuring means for measuring a period during which the regenerative current is flowing from the motor to the capacitor. Below the set voltage set value, and the regenerative period measured value measured by the regenerative period measuring means is below the preset regenerative period set value, and the average value of the torque command value or current command value given to the motor, Phase adjustment by the current phase difference adjustment means so that at least one of the average value of the effective value of the armature current detected from the current detection means and the average value of the peak value of the armature current becomes a minimum value. An inverter control device characterized by being configured to perform. The inverter control device detects AC voltage, AC voltage detection means for detecting the voltage of the AC power supply, absolute value conversion means for taking an absolute value of the AC voltage detection value detected by the AC voltage detection means, and the smoothing voltage. And a smoothing voltage detecting means, wherein the regeneration period measuring means is configured so that the absolute value of the AC voltage detected value converted by the absolute value converting means and the smoothed voltage detected value detected by the smoothed voltage detecting means are large or small. The inverter control device according to claim 2, wherein a period during which a regenerative current flows from the electric motor to the capacitor is measured based on a relationship. The current detection unit is configured to directly detect a bus current on the DC side of the orthogonal transform unit, and to detect an armature current flowing to the motor indirectly from a detection value of the bus current, and the regeneration period measurement 3. The inverter control device according to claim 2, wherein the means is configured to measure a period during which a regenerative current flows from the electric motor to the capacitor based on a detected value of the bus current. A configuration further comprising smoothing voltage detection means for detecting the smoothing voltage, and performing the phase adjustment by the current phase difference adjustment means only when the smoothing voltage detection value detected by the smoothing voltage detection means is less than an arbitrary set value The inverter control device according to claim 1, wherein the inverter control device is configured as described above. AC voltage detection means for detecting the voltage of the AC power supply, and an absolute value conversion means for taking an absolute value of the AC voltage detection value detected by the AC voltage detection means, further converted by the absolute value conversion means 5. The structure according to claim 1, wherein the phase adjustment is performed by the current phase difference adjusting means only when the absolute value of the AC voltage detection value is less than an arbitrary set value. The inverter control device described. Only when at least one of the smoothed voltage detection value detected by the smoothing voltage detection means and the absolute value of the AC voltage detection value converted by the absolute value conversion means is less than an arbitrary set value, The inverter control device according to claim 3, wherein the phase adjustment is performed by the current phase difference adjusting means. 8. The smoothing means includes a capacitor and a reactor, and a resonance frequency required by the capacitor and the reactor is set to be 40 times or more of an AC power supply frequency. The inverter control device described in 1. 9. The voltage setting value is set to be not more than 2.5 times the applied voltage when the regenerative energy charged from the electric motor to the capacitor of the smoothing means becomes zero. The inverter control device according to any one of the above. At a predetermined rotation speed and load torque, the applied voltage of the motor controlled by the drive control means is 2.5 times or less of the applied voltage when the regenerative energy charged from the motor to the capacitor is zero. The inverter control device according to any one of claims 1 to 9, wherein specifications of the electric motor are determined so as to be.

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