JP5785126B2 - Synchronous motor drive device - Google Patents

Description

  The present invention relates to a synchronous motor driving device, and more particularly to a synchronous motor driving device that supplies three-phase AC power generated by an inverter circuit to a synchronous motor.

  The synchronous motor drive device converts input AC power (hereinafter also including the meanings of AC voltage and AC current) supplied from a commercial AC power source into DC power (hereinafter also including the meanings of DC voltage and DC current) using a converter circuit. It converts, and it converts into alternating current power (alternating current) with the direct-current power inverter circuit, and drives a synchronous motor.

  The DC power inverter circuit generates a variable frequency AC current by chopping the DC voltage output from the converter circuit with an IPM (Intelligent Power Module) or the like. The refrigeration / air conditioning apparatus includes a fuse in the AC circuit unit so that the input AC current supplied from the commercial AC power supply does not exceed the current for operating the breaker.

  However, in order to maintain the continuity and comfort of the refrigeration / air-conditioning system, when the input AC current exceeds a predetermined value, the applied voltage to the compressor motor is lowered to reduce the compressor rotational speed and the AC current value is reduced. Control that does not exceed the threshold is performed.

  The control for suppressing the input AC current (hereinafter referred to as peak control control) is for preventing the fuse from being blown and maintaining the continuity of the refrigeration / air-conditioning apparatus. On the other hand, for products that have a low refrigeration capacity and can obtain an output sufficient to achieve the function even if a large current until the fuse blows does not flow in normal use, use electrical components that match the low current for cost reduction. There is. In this case, in order to protect the component, a peak control control threshold is set within the standard current of the component, and peak control control is performed.

  Further, there are the following techniques for detecting the input power factor. The technique disclosed in Japanese Patent Laid-Open No. 2001-309660 (Patent Document 1) is intended to provide an input power factor detection device for a PWM cycloconverter with a simple circuit configuration without using an analog / digital conversion circuit. Yes.

  In the input power factor detection device disclosed in Japanese Patent Laid-Open No. 2001-309660 (Patent Document 1), an input current signal and an input voltage signal detected by a current detection CT and a voltage detection transformer are respectively zero by a comparator. Compared with the voltage, an input current direction signal and an input voltage polarity signal are output. The input current direction signal and the input voltage polarity signal are input to the XOR circuit, the output clock of the clock oscillator and the output of the XOR circuit are input to the AND circuit, and the phase difference signal of both signals is output. The main controller detects the input power factor of the PWM cycloconverter from the phase difference signal and the advance / delay of the input voltage signal known in advance with respect to the input current signal.

JP 2001-309660 A

  However, products that set the peak control control threshold value with a current value that provides an output sufficient to achieve the function are designed with consideration given to the output when the commercial power supply is at the rated voltage. When the power supply is lowered, the power factor is lowered. For this reason, the electric power that can be used on the output side is reduced, and the compressor of the refrigeration / air-conditioning apparatus may not be able to output the capacity sufficiently.

  Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 2001-309660 (Patent Document 1), the power factor is calculated using the AC power before conversion and the AC power after conversion input to the converter circuit. It has not been studied in detail.

  An object of the present invention is to provide a synchronous motor driving device that can easily calculate and estimate the power source power factor of the synchronous motor driving device.

  A synchronous motor driving device according to an aspect of the present invention includes an AC power source, a converter circuit that converts an AC voltage into a DC voltage, and outputs an AC current that is detected between the AC power source and the converter circuit. Detecting circuit, DC voltage detecting circuit that detects the output DC voltage of the converter circuit, an inverter circuit that converts the DC voltage to a variable frequency AC voltage and outputs it to the synchronous motor, and is provided between the converter circuit and the inverter circuit And a control unit for controlling the inverter circuit. The control unit estimates the power source power factor based on the storage unit, the apparent power derived from the AC current, and the effective power derived from the output DC voltage. A power source power factor estimating unit for generating a PWM signal for generating a PWM signal for converting a DC voltage into an AC voltage of a variable frequency. Capacitor circuit includes a rectifier circuit for generating a rectified voltage from an AC power source, and a smoothing circuit for smoothing the DC voltage.

  Preferably, the power source power factor estimator calculates the first active power of the synchronous motor based on the instantaneous power derived from the instantaneous values of the output DC current and the output DC voltage from the DC current detection circuit. Based on the calculation unit, the proportionality constant storage unit that stores the proportionality constant for calculating the second power proportional to the first active power, the first active power and the second power, Based on the total active power calculation unit for calculating the active power, the apparent power calculation unit for calculating the apparent power based on the alternating current and the pre-stored rated AC voltage, and the third active power and the apparent power, A power source power factor calculation unit for calculating the rate;

  Preferably, the power source power factor estimator calculates the first active power of the synchronous motor based on the instantaneous power derived from the instantaneous values of the output DC current and the output DC voltage from the DC current detection circuit. Based on the calculation unit, the proportionality constant storage unit that stores the proportionality constant for calculating the second power proportional to the first active power, the first active power and the second power, A voltage effective value for calculating an AC voltage effective value based on a total active power calculating unit for calculating active power, an instantaneous value of the output DC voltage, a ripple cycle superimposed on the output DC voltage, and the first active power A power source power factor calculation for calculating a power source power factor based on the third active power and the apparent power, and an apparent power calculator for calculating the apparent power based on the output of the voltage effective value calculator and the alternating current. Part.

  Preferably, the synchronous motor driving device detects a phase of the AC voltage of the AC power supply when the AC voltage of the AC power supply reaches a predetermined voltage value, and has a pulse signal having a pulse width corresponding to the detected phase. The converter circuit further includes a reactor connected in series to the AC current detection circuit, and a short circuit that short-circuits the AC voltage of the AC power supply via the reactor. The operation of the short circuit is controlled based on the signal.

  The storage unit stores in advance the relationship data between the pulse signal and the AC voltage, and the control unit reads the relationship data and compares the relationship data with the output detected from the voltage phase detection circuit, thereby The AC voltage is calculated, and the power source power factor is calculated.

  A synchronous motor drive device according to another aspect of the present invention includes an AC power source, a converter circuit that converts an AC voltage into a DC voltage, and an AC current that is detected between an AC power source and the converter circuit. A current detection circuit; a DC voltage detection circuit that detects an output DC voltage of the converter circuit; a plurality of inverter circuits that each convert the DC voltage into an AC voltage of variable frequency and output to a plurality of synchronous motors; and a converter circuit And a plurality of DC current detection circuits provided between the plurality of inverter circuits and a control unit for controlling the plurality of inverter circuits, the control unit includes a storage unit, an apparent power derived from the AC current, and an output DC Based on the active power derived from the voltage, a plurality of power source power factor estimators for estimating the power source power factors of the plurality of synchronous motors, respectively, A plurality of PWM signal generators each generating a PWM signal for converting a voltage into an AC voltage of a variable frequency, and the converter circuit smoothes the DC voltage and a rectifier circuit that generates a rectified voltage from an AC power supply Each of the plurality of power source power factor estimators includes a first circuit of the synchronous motor based on the instantaneous power derived from the instantaneous values of the output DC current and the output DC voltage from the DC current detection circuit. An active power calculation unit for calculating active power, a proportionality constant storage unit for storing a proportionality constant for calculating a second power proportional to the first active power, a first active power, and a second power Based on the above, the total active power calculation unit for calculating the third active power, the apparent power calculation unit for calculating the apparent power from the alternating current, the rated AC voltage and the AC current stored in advance, and the third effective power Based on the power and apparent power, having a power factor calculation unit for calculating the power factor of the power supply.

  More preferably, the storage unit stores the reference power source power factor and the reference AC current effective value in advance, and the control unit reads the reference power source power factor and the reference AC current effective value from the storage unit, and from the power source power factor calculation unit. Is less than the reference power source power factor, and if the output from the AC current detection circuit is greater than the reference AC current effective value, the voltage applied to the synchronous motor is reduced, and the AC current detection circuit The current value used for the peak control control is changed so that the output from is not larger than the predetermined current value.

  Preferably, the storage unit further stores a component protection current value that can be received by a component used in the synchronous motor driving device and a peak control current threshold value for peak control control, and the reference power source power factor is rated. The reference AC current effective value is set as the difference between the peak control current threshold and the error current when the rated voltage is applied, and the control unit When the output from the rate calculation unit is smaller than the reference power source power factor and the output from the AC current detection circuit is larger than the reference AC current effective value, the threshold value of the current value used for peak control control is determined from the peak control current threshold value. Switch to the component protection current value.

  More preferably, the control unit is used for peak control control when the peak control current threshold is set to the component protection current value and the output from the power source power factor calculation unit is larger than the reference power source power factor. The threshold value of the current value is switched from the component protection current value to the peak control current threshold value.

  More preferably, the control unit is used for peak control control when the peak control current threshold is set to the component protection current value and the output from the AC current detection circuit is smaller than the reference AC current effective value. The threshold value of the current value to be switched is switched from the component protection current value to the peak control current threshold value.

  According to the present invention, the power factor of the refrigeration / air conditioning apparatus can be calculated. Further, since the power factor can be calculated, an output for satisfying the function can be obtained without lowering the capacity even when the commercial power supply voltage is lowered, and a highly comfortable refrigeration / air conditioning apparatus can be provided. it can.

The configuration and operation of synchronous motor drive device MD1 according to Embodiment 1 of the present invention will be described. 3 is a diagram illustrating a specific example of a converter circuit 2. FIG. The configuration and operation of the microcomputer A1 according to the first embodiment of the present invention will be described. In synchronous motor drive device MD1 which concerns on embodiment of this invention, it is a schematic diagram which shows the waveform of the three-phase alternating current which the inverter circuit 3 outputs. It is a figure which shows synchronous motor drive device MD2 of the modification of Embodiment 1. FIG. The configuration and operation of the synchronous motor drive device MD11 according to Embodiment 2 of the present invention will be described. The configuration and operation of the microcomputer A11 will be described. It is a figure for demonstrating the structure and operation | movement of synchronous motor drive device MD1A which concern on Embodiment 3 of this invention. It is a figure which shows the relationship between active electric power and an effect DC voltage. The configuration and operation of the microcomputer A21 will be described. It is a circuit diagram which shows the structure of the synchronous motor drive device MDA (commercial AC power supply 100V) which concerns on Embodiment 4. FIG. It is a circuit diagram which shows the structure of the synchronous motor drive device MDB (commercial AC power supply 200V) which concerns on the modification of Embodiment 4. FIG. It is a figure for demonstrating the relationship between the commercial alternating current power supply 1 and the output of a zero cross detection circuit. It is an example which shows the relationship between an active power and a power supply power factor. It is a figure which shows the correspondence of a compressor speed and a power factor. 18 is a flowchart for explaining the operation of the sixth embodiment. 18 is a flowchart for explaining the operation of the seventh embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part in a figure, and the description is not repeated.

[Embodiment 1]
FIG. 1 illustrates the configuration and operation of a synchronous motor drive device MD1 according to Embodiment 1 of the present invention.

  Referring to FIG. 1, synchronous motor drive device MD1 includes a converter circuit 2, an inverter circuit 3, a current detection resistor (shunt resistor) R1, a resistor Rdc1, a resistor Rdc2, a DC current detection circuit 5, and a microcomputer A1. The Although not shown, the microcomputer A1 includes an IPM that controls the chopping operation of the inverter circuit 3.

  Converter circuit 2 converts AC power supplied from commercial AC power supply 1 having voltage effective value Vac and current effective value Iac into DC voltage Vdc, and outputs the DC voltage Vdc between positive DC line PL1 and negative DC line PL2.

  FIG. 2 is a diagram illustrating a specific example of the converter circuit 2. FIG. 2A shows a converter circuit that outputs a DC voltage Vdc from an AC voltage having a voltage effective value Vac of, for example, 200V. The AC voltage is rectified and smoothed by the diode bridge DB and the capacitor C and output as a DC voltage Vdc.

  FIG. 2B is a converter circuit that outputs a DC voltage Vdc equivalent to that in FIG. 2A from an AC voltage having a voltage effective value Vac of, for example, 100V. The AC voltage is converted into a DC voltage Vdc boosted by a voltage doubler circuit composed of a diode bridge DB, a capacitor C1, and a capacitor C2. A converter circuit having a necessary configuration is selected according to the value of the effective voltage value Vac supplied to the synchronous motor drive device MD1.

  Referring to FIG. 1 again, inverter circuit 3 includes a three-phase (U phase / V phase / W phase) inverter (Qu / Qx, Qv / Qy) connected between positive DC line PL1 and negative DC line PL2. , Qw / Qz). Each of the three-phase inverters converts the DC voltage Vdc into a three-phase AC current (U phase / V phase / W phase) and supplies it to the synchronous motor M4.

  The output side of the converter circuit 2 and the input side of the inverter circuit 3 are connected by a positive DC line PL1 and a negative DC line PL2, and a current detection resistor R1 is provided on the negative DC line PL2 between the two circuits. .

  The direct current detection circuit 5 detects the direct current Idc flowing through the inverter circuit 3 based on the voltage generated at both ends of the current detection resistor R1, amplifies it, and outputs it to the microcomputer A1 as the direct current monitor signal Idc_sig.

  Resistor Rdc1 and resistor Rdc2 are connected in series between positive DC line PL1 and negative DC line PL2 to form a DC voltage monitor circuit. A DC voltage monitor signal Vdc_sig1 obtained by dividing the DC voltage Vdc by both resistances is output to the microcomputer A1 from the connection point between the resistors Rdc1 and Rdc2.

  The AC current detection circuit 16 is a so-called current sensor, detects the effective current value Iac of the commercial AC power supply 1, and outputs it to the microcomputer A1 as an AC current monitor signal Iac_sig.

  As the alternating current detection circuit 16, a sensor called a current transformer is generally used. A current transformer is a device that converts alternating current into a voltage that can be input to an internal circuit (for example, a microcomputer). The current transformer can be input to a microcomputer with an alternating current waveform or smoothed into direct current and input to the microcomputer. This is a component that can detect an AC current.

  When the input AC current information is an AC waveform, the microcomputer detects the current equivalent voltage value for each sampling period and averages it for each power supply period to calculate the AC current effective value. On the other hand, when the input is performed with a DC waveform, the relationship between the DC voltage value and the effective value of the AC current is stored in advance in the microcomputer to obtain the AC current effective value. In the case of input with a DC waveform, full-wave rectification or half-wave rectification is performed on the current-equivalent voltage output with an AC waveform, which is converted into a DC with a smoothing capacitor and input to a microcomputer. In this way, it is possible to detect the effective value of the alternating current.

(Constitution)
FIG. 3 illustrates the configuration and operation of the microcomputer A1 according to the first embodiment of the present invention.

  Referring to FIG. 3, microcomputer A1 includes a PWM signal generation unit 7 and a power source power factor estimation unit 6. The PWM signal generation unit 7 generates a PWM signal and outputs it to the inverter circuit 3. The power source power factor estimation unit 6 is effective based on the DC current monitor signal Idc_sig output from the DC current detection circuit 5, the PWM signal output from the PWM signal generation unit 7, the DC voltage monitor signal Vdc_sig1, and the AC current monitor signal Iac_sig. The power P is calculated, and the active power P is used to calculate the total active power obtained by adding consumption and other power in proportion to the active power due to heat loss or the like. Calculate the power factor.

  The power source power factor estimation unit 6 includes an instantaneous current distribution unit 61, an instantaneous power calculation unit 62, an active power calculation unit 63, a total active power calculation unit 64, and a power source power factor calculation unit 65. Furthermore, the power source power factor estimating unit 6 stores a synchronous motor pole number storage unit 612 that stores the number of poles of the synchronous motor M4 that is driven by the synchronous motor driving device MD1, and a detection cycle that stores a detection cycle of the DC current Idc of the inverter circuit 3. Storage unit 613, detection electric angle setting unit 611 that sets the pitch of the electric angle of the motor that detects DC current Idc, and the voltage value of DC voltage Vdc output by converter circuit 2 at the time when DC current Idc is detected An instantaneous DC voltage detector 621 is included. Furthermore, the power source power factor estimation unit 6 includes a proportional constant storage unit 642, an apparent power calculation unit 651, and a rated AC voltage storage unit 652.

(Detection of instantaneous current Iu (t) / Iv (t) / Iw (t))
The instantaneous current distribution unit 61 converts the DC current Idc flowing through the inverter circuit 3 at time t based on the DC current monitor signal Idc_sig detected at a predetermined time t to each of the three-phase (U-phase / V-phase / W-phase) inverters. Is distributed to instantaneous currents Iu (t), Iv (t), and Iw (t). The DC current Idc of the inverter circuit 3 is the sum of currents flowing from the three-phase inverters to the negative DC line PL2. The current flowing through each of the three-phase inverters is controlled by the PWM signal output from the PWM signal generation unit 7 included in the microcomputer A1.

  The instantaneous current distribution unit 61 obtains a change in the DC current monitor signal Idc_sig at the timing immediately before and after switching of each of the three-phase inverters. The change is distributed to the three-phase inverters based on the switching information of the PWM signal, so that the direct current Idc flowing through the inverter circuit 3 is distributed to the three-phase inverters.

  The instantaneous DC voltage detection unit 621 detects the value of the DC voltage Vdc output from the converter circuit 2 at the set time based on the input DC voltage monitor signal Vdc_sig 1 and outputs the detected value to the instantaneous power calculation unit 62.

(Calculation of instantaneous power p (t))
The instantaneous power calculator 62 calculates the instantaneous power p (t) at a predetermined time t based on the three-phase instantaneous currents Iu (t), Iv (t), and Iw (t). Instantaneous DC voltage detector 621 detects and outputs voltage value Vdc of DC voltage Vdc at time t output from converter circuit 2. The instantaneous power p (t) is calculated by the following equation based on the instantaneous currents Iu (t), Iv (t), and Iw (t) and the DC voltage Vdc output from the instantaneous DC voltage detector 621. In the following expressions, the symbol “*” means a multiplication symbol, and the symbol “/” means a division symbol.

p (t) = pu (t) + pv (t) + pw (t)
Here, pu (t), pv (t), and pw (t) are the instantaneous powers of the U-phase, V-phase, and W-phase, respectively, and are obtained by the following equations.

pu (t) = Vdc * U-phase PWM duty ratio * Iu (t)
pv (t) = Vdc * V-phase PWM duty ratio * Iv (t)
pw (t) = Vdc * W-phase PWM duty ratio * Iw (t)
Here, the PWM duty ratio is a duty ratio of the PWM waveform.

(Instantaneous power detection times t1 to tn)
FIG. 4 is a schematic diagram showing a waveform of a three-phase alternating current output from the inverter circuit 3 in the synchronous motor driving device MD1 according to the embodiment of the present invention. With reference to FIG. 4, the detection times t1 to tn of the instantaneous power p (t) set at the period T of one mechanical rotation of the synchronous motor M4 will be described. The horizontal axis indicates a range corresponding to one mechanical rotation of the synchronous motor M4, that is, a mechanical angle of 360 °. The vertical axis schematically shows the output current waveform for each phase (U phase / V phase / W phase) of the inverter circuit 3.

  In the case of a synchronous motor having a four-pole three-phase structure, it makes two electrical revolutions during one mechanical revolution. That is, the mechanical angle 360 ° corresponds to the electrical angle 720 °. In FIG. 4, in the period T of one mechanical rotation of the synchronous motor, the time at the electrical angle of 30 ° is t1, and thereafter, the detection time is set for every electrical angle of 60 ° (pitch at the electrical angle of 60 °). The last detection time tn in the cycle T is a time corresponding to an electrical angle of 690 °, and the total number of detections is 12 times.

  In the first embodiment, the detection of the instantaneous power has been described by setting the electrical angle 60 ° as the cycle. The calculation accuracy of the active power can be improved by setting the instantaneous power detection time (the pitch of the electrical angle to be set) smaller.

  Actually, considering the processing performance of the microcomputer A1 in FIG. 1 and the relationship with other arithmetic processing, the pitch of the electrical angle for detecting the instantaneous power p (t) is 1 °, 10 °, 30 ° or It is preferable to select from a period of 60 °. However, if the pitch of the electrical angle to be selected is too large, the accuracy of the calculation result output by the active power calculation unit is reduced. Therefore, the pitch of the electrical angle to be set is preferably 60 ° or less.

  With reference to FIG. 3 again, operations of the detected electrical angle setting unit 611, the synchronous motor pole number storage unit 612, the detection cycle storage unit 613, and the active power calculation unit 63 included in the power source power factor estimation unit 6 will be described.

  The synchronous motor pole number storage unit 612 stores the pole number of the synchronous motor M4 driven by the inverter circuit 3. In the first embodiment, a synchronous motor having a four-pole three-phase structure is described as an example. In this case, the synchronous motor pole number storage unit 612 stores information indicating that the synchronous motor has four poles. The synchronous motor driving device MD1 according to the first embodiment can easily control a synchronous motor having another structure by changing information to be written in the synchronous motor pole number storage unit 612.

  The detection cycle storage unit 613 stores a pitch of an electrical angle for detecting the instantaneous power p (t) in a cycle T of one mechanical rotation of the synchronous motor M4. The synchronous motor driving device MD1 according to the present embodiment can change the pitch of the electrical angle, and can calculate the effective power with the accuracy required by the user.

  The detected electrical angle setting unit 611 outputs the time t at which the DC current monitor signal Idc_sig output from the DC current detection circuit 5 is detected to the instantaneous current distribution unit 61. The instantaneous current distribution unit 61 calculates the instantaneous currents Iu (t), Iv (t), and Iw (t) flowing through the three-phase inverters of the inverter circuit 3 at the designated time t.

  Based on the information output from the synchronous motor pole number storage unit 612 and the detection cycle storage unit 613, the detection electrical angle setting unit 611 detects the DC current Idc flowing through the inverter circuit 3 relative to the instantaneous current distribution unit 61 at the detection time t1. ~ Tn is notified.

(Calculation of active power P)
The active power calculation unit 63 integrates the instantaneous power p (t) output from the instantaneous power calculation unit 62 over a predetermined period T, and divides the integration result by the period T to calculate the active power P. In the case of a motor, first, the time for which the motor makes one mechanical rotation is defined as a period T, and a plurality of times t1 to tn are set over the period T. The active power P consumed by the synchronous motor M4 is obtained by the following formula 1 obtained by dividing the sum of the instantaneous powers p (t1) to p (tn) at each time by the period T.

P = (p (t1) + p (t2) +... + P (tn)) / T.
The active power calculation unit 63 calculates the effective power P consumed by the synchronous motor M4 by dividing the sum of the instantaneous powers p (t1) to p (tn) at each time by the period T as described in Equation 1. And output to the total active power calculation unit 64. In the following, a formula for calculating the active power P will be described using a specific number of poles of the synchronous motor M4 and the pitch of the detected electrical angle as an example.

  When the synchronous motor M4 has a four-pole three-phase structure, one mechanical rotation corresponds to two electrical rotations. Therefore, when the instantaneous power p (t) of the inverter circuit 3 is detected at an electrical angle of 60 °, the number of detections is 12. Therefore, the active power P is calculated as follows.

P = (p (t1) +... + P (t12)) / 12
The effective power P of the four-pole three-phase synchronous motor is obtained by the above formula.

  When the synchronous motor M4 has a six-pole three-phase structure, one mechanical rotation corresponds to three electrical rotations. Therefore, when the instantaneous power p (t) of the inverter circuit 3 is detected at a pitch of an electrical angle of 60 °, the number of detections is 18 times. The active power P is calculated as follows.

P = (p (t1) +... + P (t18)) / 18
The effective power P of the 6-pole 3-phase synchronous motor is obtained by the above formula.

Referring to FIG. 1 again, the effective values of the AC voltage and AC current supplied from commercial AC power supply 1 to synchronous motor drive device MD1 are Vac and Iac, respectively. When the phase difference between the AC voltage and the AC current is “θ”, the effective power is Vac * Iac * cos (θ). Here, assuming that the total active power consumed by the synchronous motor driving device MD1 is P_md1,
Vac * Iac * cos (θ) = P_md1
This relationship is established.

  In the synchronous motor driving device MD1 shown in FIG. 1, it is considered that the effective power supplied from the commercial AC power source 1 to the converter circuit 2 constituted by a diode bridge or the like and the output power of the converter circuit 2 are substantially equal. The output power of the converter circuit 2 is mainly consumed by the synchronous motor M4 driven by the inverter circuit 3. The active power of the synchronous motor M4 is obtained as the active power P output from the active power calculator 63 shown in FIG. The calculation formula of the active power P of the synchronous motor M4 is as shown in Formula 1.

  Furthermore, as for the output power of the converter circuit 2, in addition to the effective power P of the synchronous motor M4, the power consumption due to the heat loss of the microcomputer A1 part that controls the inverter circuit 3 may not be negligible. The power for the heat loss of the IPM (microcomputer A1) that controls the chopping operation of the inverter circuit 3 is P_ipm1. This P_ipm1 is proportional to the active power P of the synchronous motor M4 driven by the inverter circuit 3. If the proportionality constant is k1, the following relationship is established.

P_ipm1 = k1 * P
The proportionality constant k1 is a value obtained by experiments or the like, and is stored in the proportionality constant storage unit 642.

  From the above, the total effective power P_md1 consumed by the synchronous motor driving device MD1 is the sum of the effective power P of the synchronous motor M4 and the power P_ipm1 corresponding to the heat loss of the IPM. The relationship between the active power supplied from the commercial AC power supply 1 to the converter circuit 2 and the total active power P_md1 consumed by the synchronous motor driving device MD1 is shown below.

Vac * Iac * cos (θ) = P_md1 Equation 2
P_md1 = P + P_ipm1 = (1 + k1) * P Equation 3
Below, the calculation method of a power supply power factor is demonstrated.

(Calculation of power factor)
Next, when the fluctuation of the commercial AC power source 1 can be almost ignored, the power source power factor of the synchronous motor driving device MD1 is calculated. By multiplying the alternating current effective value of the alternating current monitor signal Iac_sig detected by the alternating current detection circuit (current transformer) 16 of FIG. 1 by the rated alternating voltage effective value of the rated alternating voltage storage unit 652 stored in advance. Apparent power (S) can be calculated. Since the active power (P) can also be calculated as described above, the power source power factor can be calculated as follows.

Apparent power (S) = AC voltage effective value (V) x AC current effective value (I)
Active power (P) = AC voltage effective value (V) × AC current effective value (I) × power source power factor (cos θ)
= Apparent power (S) x Power source power factor (cosθ)
Power source power factor (cos θ) = active power (P) / apparent power (S)
As described above, by adopting the configuration of the synchronous motor driving device MD1 of the first embodiment, the general-purpose arithmetic processing function provided in the microcomputer A1 including the IPM can be used without adding complicated circuit components. Power factor can be calculated.

[Modification of Embodiment 1]
FIG. 5 is a diagram showing a synchronous motor driving device MD2 according to a modification of the first embodiment. With reference to FIG. 5, the configuration and operation of synchronous motor drive device MD2 will be described.

  The synchronous motor driving device MD2 shown in FIG. 5 includes a converter circuit 2, an inverter circuit 3A, a shunt resistor R1, a resistor Rdc1, a resistor Rdc2, a current detection circuit 53, and a microcomputer A3.

  Converter circuit 2 converts AC power supplied from commercial AC power supply 1 having voltage effective value Vac and current effective value Iac into DC voltage Vdc, and outputs the DC voltage Vdc between positive DC line PL1 and negative DC line PL2. The converter circuit 2 shown in FIG. 2 (a) or FIG. 2 (b) is appropriately selected according to the value of the voltage effective value Vac of the AC power supplied to the synchronous motor driving device MD2.

  The inverter circuit 3 has a two-phase (U phase / V phase / W phase) inverter (Qu / Qx, Qv / Qy, Qw / Qz) connected between the positive DC line PL1 and the negative DC line PL2. Each of the three-phase inverters converts the DC voltage Vdc into a three-phase AC current (U phase / V phase / W phase) and supplies the same to the synchronous motor 4.

  The microcomputer A3 generates a PWM (Pulse Width Modulation) signal and controls switching of each of the three-phase inverters. By this switching control, the inverter circuit 3A generates a three-phase AC current from the DC voltage Vdc.

  The output side of the converter circuit 2 and the input side of the inverter circuit 3A are connected by a positive DC line PL1 and a negative DC line PL2, and a shunt resistor R1 is provided on the negative DC line PL2 between the two circuits.

  Resistor Rdc1 and resistor Rdc2 are DC-connected between positive DC line PL1 and negative DC line PL2 to form a DC voltage monitor circuit. A DC voltage monitor signal Vdc_sig2 obtained by dividing the DC voltage Vdc by both resistors is output from the connection point of the resistors Rdc1 and Rdc2 to the microcomputer A3.

  In FIG. 5, the differences from the first embodiment are as follows. That is, current detection resistors Ru, Rv, and Rw are arranged between the three-phase (U-phase / V-phase / W-phase) inverters constituting the inverter circuit 3A and the negative DC line PL2. In the first embodiment, the DC current Idc of the inverter circuit 3 is detected by the resistor R1 that is also a shunt resistor.

  However, in the modification of the first embodiment, the potential at the connection point between each of the three-phase inverters and the current detection resistors Ru, Rv, Rw is input to the current detection circuit 53. The current detection circuit 53 converts the value of the electric potential of each phase into DC current signals Iru, Irv, and Irw flowing through the inverters, and outputs them to the microcomputer A3. Even with the circuit configuration as described above, a more accurate power factor can be calculated.

[Embodiment 2]
In the first embodiment, the case where the fluctuation of the commercial AC power supply 1 can be almost ignored is examined. In the second embodiment, the case where the fluctuation cannot be ignored is examined. For example, by calculating the electric power of a motor used for a fan other than the compressor and adding it to the active power, it is possible to increase the accuracy of the active power and calculate a more accurate power source power factor.

  FIG. 6 illustrates the configuration and operation of the synchronous motor drive device MD11 according to the second embodiment of the present invention.

  Referring to FIG. 6, synchronous motor drive device MD11 converts the input AC power supplied from commercial AC power supply 1 whose effective values of AC voltage and AC current are Vac and Iac, respectively, into DC voltage Vdc. And a converter circuit 2 for outputting between the positive DC line PL1A and the negative DC line PL2A. Unlike synchronous motor drive device MD1 shown in FIG. 1, synchronous motor drive device MD11 includes an inverter circuit 31 and an inverter circuit 32 connected in parallel to positive DC line PL1A and negative DC line PL2A.

  Synchronous motor drive device MD11 further includes microcomputer A11, resistors Rdc11 and Rdc12, resistors R11 and R12, and DC current detection circuits 51 and 52. The microcomputer A11 includes an IPM, similar to the microcomputer A1 of FIG.

  Inverter circuits 31 and 32 generate a three-phase AC current from DC voltage Vdc, and supply the three-phase AC current to compressor synchronous motor M41 of the refrigeration / air conditioner and fan synchronous motor FM42 of the outdoor unit, respectively. The microcomputer A11 generates the PWM1 signal and the PWM2 signal, and controls the switching operations of the inverter circuits 31 and 32, respectively.

  A current detection resistor R11 is provided on the negative DC line PL2A that connects the converter circuit 2 and the inverter circuit 31. A current detection resistor R12 is provided on the negative DC line PL2A connecting the converter circuit 2 and the inverter circuit 32. Based on the voltages generated at both ends of current detection resistors R11 and R12, DC current detection circuit 51 and DC current detection circuit 52 detect and amplify DC currents Idc1 and Idc2 flowing through inverter circuits 31 and 32, respectively. DC detection signals Idc1_sig and Idc2_sig are output to the microcomputer A11.

(Constitution)
FIG. 7 illustrates the configuration and operation of the microcomputer A11. Referring to FIG. 7, microcomputer A11 includes power source power factor estimators 6M and 6FM and PWM signal generators 7M and 7FM. PWM signal generation unit 7M and PWM signal generation unit 7FM generate a PWM1 signal and a PWM2 signal, respectively, and output them to inverter circuits 31 and 32.

  The power source power factor estimation unit 6M includes a synchronous motor pole number storage unit 612M, a detection cycle storage unit 613M, a proportional constant storage unit 642M, a rated AC voltage storage unit 652M, an instantaneous current distribution unit 61M, and a power source power factor calculation unit 65M.

  On the other hand, the power source power factor estimation unit 6FM includes a synchronous motor pole number storage unit 612FM, a detection cycle storage unit 613FM, a proportional constant storage unit 642FM, a rated AC voltage storage unit 652FM, an instantaneous current distribution unit 61FM, and a power source power factor calculation unit 65FM. Have.

  The synchronous motor pole number storage unit 612M and the synchronous motor pole number storage unit 612FM store numerical values indicating the motor pole numbers of the compressor synchronous motor M41 and the fan synchronous motor FM42, respectively. The detection cycle storage units 613M and 613FM store the pitch of the electrical angle for detecting the instantaneous power. In the proportional constant storage units 642M and 642FM, the ratio of the electric power corresponding to the heat loss of the IPM (microcomputer A11) to the effective electric power of the synchronous motor obtained through experiments or the like is stored. Each rated AC voltage storage unit 652M, 652FM stores the value of the rated AC voltage of the product.

Referring to FIG. 6 again, if the phase difference between the input AC voltage and the input AC current of commercial AC power supply 1 is “θ”, the effective power is Vac * Iac * cos (θ). Assuming that the total active power consumed by the synchronous motor driving device MD11 is P_md11, the value of the effective power of both is
Vac * Iac * cos (θ) = P_md11
This relationship is established.

  7, the proportionality constant storage unit 642M stores the proportionality constant k1, and the second power supply power factor estimation unit 6FM stores the proportionality constant k2 in the proportionality constant storage unit 642FM. . The effective power of the compressor synchronous motor M41 obtained by the power source power factor estimating unit 6M is P_comp, and the effective power of the fan synchronous motor FM42 obtained by the power source power factor estimating unit 6FM is P_fan.

  Then, the power P_ipm11 corresponding to the heat loss of the IPM (microcomputer A11) resulting from the chopping operation control of the inverter circuits 31 and 32 is obtained by the following equation.

P_ipm11 = k1 * P_comp + k2 * P_fan
Therefore, the total effective power P_md11 of the synchronous motor driving device MD11 including P_comp and P_fan is
Vac * Iac * cos (θ) = P_md11
P_md11 = (1 + k1) * P_comp + (1 + k2) * P_fan
It becomes.

  Using this calculated active power, a power source power factor with higher accuracy can be calculated for the synchronous motor driving device MD11. With the configuration of the second embodiment, the synchronous motor driving device MD11 uses the general-purpose arithmetic processing function provided in the microcomputer A11 that operates as an IPM, so that it is more accurate without adding complicated circuit components. Electric power factor can be calculated.

[Embodiment 3]
In the third embodiment, unlike the first and second embodiments, even if the commercial AC power supply 1 fluctuates, a highly accurate power factor is calculated. FIG. 8 is a diagram for explaining the configuration and operation of synchronous motor drive device MD1A according to Embodiment 3 of the present invention. Referring to FIG. 8, the configuration of synchronous motor drive device MD1A includes a microcomputer A21 instead of microcomputer A1 as compared with the configuration of synchronous motor drive device MD1 of the first embodiment. Since the other configuration of synchronous motor drive device MD1A is the same as that of synchronous motor drive device MD1, description thereof will not be repeated here.

  A method for calculating the voltage effective value Vac of the commercial AC power supply 1 shown in FIG. 8 will be described. Since the output current of the converter circuit 2 increases as the rotational speed of the synchronous motor M4 increases, the DC voltage Vdc of the converter circuit 2 decreases.

  That is, the DC voltage Vdc of the converter circuit 2 that supplies the active power P to the synchronous motor M4 is lower than when the converter circuit 2 does not output the active power P. The drop of the DC voltage Vdc is defined as a dropped DC voltage ΔVdc.

  The drop DC voltage ΔVdc has a negative value, and is a drop voltage value using the DC voltage Vdc as a reference value when the converter circuit 2 is not supplying the active power P to the synchronous motor M4.

  For example, when converter circuit 2 shown in FIG. 2A outputs active power P, voltage effective value Vac, DC voltage Vdc, and dropped DC voltage ΔVdc have the following relationship.

Vac = (Vdc−ΔVdc) / √2
= (Vdc + abs (ΔVdc)) / √2 Equation 5
Here, √2 is the square root of 2, and abs (ΔVdc) is the absolute value of ΔVdc.

  As another example, when the converter circuit 2 (voltage doubler circuit) shown in FIG. 2B outputs active power P, the voltage effective value Vac, the DC voltage Vdc, and the drop DC voltage ΔVdc have the following relationship: .

Vac = (Vdc−ΔVdc) / 2 / √2
= (Vdc + abs (ΔVdc)) / 2 / √2 Equation 51
One of the equations is selected based on the circuit configuration of the converter circuit 2.

  A method for calculating the drop DC voltage ΔVdc will be described below. FIG. 9 is a diagram showing the relationship between the active power and the effective DC voltage. Referring to FIG. 9, six graphs showing changes in the drop DC voltage ΔVdc (vertical axis) with respect to the active power P (horizontal axis) of the synchronous motor M4 are shown. The six graphs can be broadly divided into a group with a commercial AC voltage frequency of 50 Hz and a group with 60 Hz. Each group is further configured by a graph when the effective value of the AC voltage is 90V, 100V, and 110V. As shown in the six graphs, when the active power P of the synchronous motor M4 increases, the drop DC voltage ΔVdc decreases (the absolute value of ΔVdc increases). That is, the DC voltage Vdc output from the converter circuit 2 decreases.

  As shown in FIG. 9, it can be seen that the active power P and the drop DC voltage ΔVdc have a nearly inverse relationship, and the relationship further changes with the frequency of the input AC voltage. Therefore, for each frequency of the commercial AC voltage, a data table (hereinafter also simply referred to as a data table) of the active power P and the drop DC voltage ΔVdc is stored in the microcomputer A21, and the active power P and the commercial AC voltage. By specifying the frequency, it is possible to obtain the drop DC voltage ΔVdc.

  FIG. 10 illustrates the configuration and operation of the microcomputer A21. Referring to FIG. 10, power supply power factor estimation unit 6A includes a voltage effective value calculation unit 641 instead of rated AC voltage storage unit 652, as compared with power supply power factor estimation unit 6 of FIG. The voltage effective value calculation unit 641 receives the effective power P output from the active power calculation unit 63, the DC voltage Vdc and the ripple period f_rpl from the instantaneous DC voltage detection unit 621, and calculates the voltage effective value Vac as an apparent power. To the unit 651A. The other configuration of power source power factor estimating unit 6A is the same as that of power source power factor estimating unit 6, and therefore description thereof will not be repeated here.

  The voltage effective value calculation unit 641 shown in FIG. 10 calculates the voltage effective value Vac based on the ripple period f_rpl, the DC voltage Vdc, the active power P, and the data table.

  The frequency of the commercial AC power supply 1 is determined from the ripple cycle f_rpl output from the instantaneous DC voltage detector 621, and the data group of the determined frequency is selected from the two data groups stored in the data table.

  As described above, the DC drop voltage ΔVdc corresponding to the active power P of the synchronous motor M4 is determined. Furthermore, based on the active power P output from the active power calculation unit 63, the drop DC voltage ΔVdc is determined with reference to the data table.

  The voltage effective value calculation unit 641 applies the determined drop DC voltage ΔVdc and the DC voltage Vdc output from the instantaneous DC voltage detection unit 621 to Formula 5 or Formula 51, calculates the voltage effective value Vac, and sends it to the apparent power calculation unit 651. Output.

  Instead of storing the relationship between the active power P and the drop DC voltage ΔVdc in the form of a data table in the microcomputer A21, the relationship between the two may be set as an approximate expression for each AC voltage frequency and may be processed. The approximate expression may be a quadratic expression, or the range of the active power P may be divided as appropriate, and the divided power section may be approximated by a primary expression.

  The drop DC voltage ΔVdc may be calculated according to the frequency with which the rotation speed of the synchronous motor M4 changes. For example, the DC voltage drop ΔVdc may be calculated when the synchronous motor M4 continuously rotates at the same rotation speed for TA seconds or more. When the effective power P does not change over a certain period, the voltage effective value Vac with less error can be estimated by this calculation method. The time TA set as the continuation period is set in advance in the microcomputer A21.

  With the configuration of the third embodiment, the voltage effective value Vac of the commercial AC power source 1 during the operation period of the synchronous motor M4 can be detected in correspondence with the frequency of the commercial AC power source 1 and the circuit configuration of the converter circuit 2. Even if the AC voltage varies during the operation period, the effective voltage value Vac can be detected.

  By calculating the power source power factor using the voltage effective value Vac calculated above as in the first embodiment, a more accurate power source power factor can be calculated and estimated.

[Embodiment 4 and its modifications]
FIG. 11 is a circuit diagram showing a configuration of a synchronous motor driving device MDA (commercial AC power supply 100V) according to the fourth embodiment. In the fourth embodiment, the power factor of the synchronous motor driving device MDA when the commercial AC power source 1 does not fluctuate is calculated.

  Referring to FIG. 11, synchronous motor drive device MDA converts converter power (boost converter) 2 </ b> A that converts AC power supplied from commercial AC power supply 1 into DC power, and outputs a zero cross detector (voltage phase detection circuit). 22, an AC current detection circuit 23, a microcomputer (switching control unit) A 1, an inverter circuit 351, a DC voltage detection circuit 321 and a DC current detection circuit 331. Here, the microcomputer A1 is used for explanation, but the present invention is not limited to this, and any of the microcomputers A11, A21, and A3 may be used.

  In addition, it comprises a converter circuit (boost converter) 2A that converts AC power supplied from the commercial AC power source 1 into DC power and outputs it, a zero-cross detector 22, an AC current detector 23, and a microcomputer (switching controller) A1. This circuit is also referred to as a DC power supply device 120A.

  Converter circuit 2 </ b> A includes a reactor 211, rectifier circuits 212 and 215, smoothing capacitors 213 and 214, and a transistor 216.

  Reactor 211 is connected to the input side (commercial AC power supply 1 side) of rectifier circuit 212, and energy storage and release are switched by on / off of transistor 216.

  The rectifier circuit 212 is a bridge-type single-phase full-wave rectifier circuit composed of four diodes 212 a to 212 d, and full-wave rectifies the AC current supplied from the commercial AC power supply 1 via the reactor 211. I do.

  Smoothing capacitors 213 and 214 are connected to the output side (synchronous motor M4 side) of rectifier circuit 212, and smooth the full-wave rectified wave output from rectifier circuit 212.

  The rectifier circuit 215 is a bridge-type single-phase full-wave rectifier circuit composed of four diodes 215a to 215d. The rectifier circuit 215 switches the energy storage and discharge of the reactor 211 in accordance with on / off of the transistor 216. . In other words, the transistor 216 functions as a switching element that performs an on / off operation so as to switch energy storage and discharge with respect to the reactor 211.

  The transistor 216 (corresponding to a switching element) is turned on and off in accordance with an instruction (switching signal d) from the microcomputer (switching control unit) 24, and stores and releases energy to and from the reactor 211 via the rectifier circuit 215. Switch.

  The zero cross detector 22 detects a zero cross point of the commercial AC power supply 1 (specifically, a point at which the AC voltage is “0”). A zero cross signal a indicating the detected zero cross point is output to the switching control unit 24.

  The AC current detection circuit 23 is interposed between the commercial AC power supply 1 and the reactor 211, and detects an input current I0 flowing through the reactor 211. Specifically, the switching control unit 24 includes a CPU (Central Processing Unit) and the like. Detected by the zero cross signal a from the zero cross detection unit 22, the input current I 0 (AC current monitor signal b) detected by the AC current detection circuit 23, the DC current c detected by the DC current detection circuit 331, and the DC voltage detection circuit 321. Based on the DC voltage Vdc (output voltage value Vdc), the operation of the transistor 216 is controlled.

  Next, FIG. 12 is a circuit diagram showing a configuration of a synchronous motor driving device MDB (commercial AC power supply 200V) according to a modification of the fourth embodiment. The synchronous motor drive device MDB will be described in comparison with the synchronous motor drive device MDA described above. Referring to FIG. 12, synchronous motor drive device MDB includes a smoothing capacitor 213B instead of smoothing capacitors 213 and 214 of FIG. Since other configurations and operations of synchronous motor drive device MDB are the same as other configurations and operations of synchronous motor drive device MDA, description thereof will not be repeated here.

  For the synchronous motor driving devices MDA and MDB according to the fourth embodiment and its modification, the DC power supply is detected by detecting the apparent power and the effective power in the same manner as the synchronous motor driving devices MD1 and MD11 according to the first and second embodiments. Even when there is a circuit, it is possible to calculate and estimate the power factor.

[Embodiment 5]
In the fifth embodiment, even if the commercial AC power source 1 fluctuates, the synchronous motor driving device calculates a power source power factor with high accuracy. First, a synchronous motor driving device (not shown) according to the fifth embodiment is a synchronous motor driving device in which a DC power supply circuit is added to the synchronous motor driving device MD1 according to the first embodiment. The DC power supply circuit refers to the DC current device 120, and the DC current device 120 includes the AC current detection circuit 16 and the converter circuit 2.

  Next, when the DC power supply circuit 120 shown in FIG. 1 is formed of an electrical board, the DC voltage is boosted and supplied to the inverter circuit 3, so that there is no fixed relationship between the active power and the dropped DC voltage.

  For this reason, the commercial AC power source 1 cannot be estimated from the dropped DC voltage as described in the third embodiment. Therefore, the commercial AC power source 1 is estimated based on the clock width detected from the zero cross detector.

  The zero cross detection circuit detects the point where the AC power supply voltage becomes zero, but from another point of view, the output is continuously turned ON while the AC power supply voltage reaches the predetermined reference voltage, and the predetermined reference voltage is set. In the following, the circuit operates to turn off the output. Switching timing control of the DC power supply circuit is performed using the edge of the zero cross signal as a trigger of detection timing.

FIG. 13 is a diagram for explaining the relationship between the commercial AC power supply 1 and the output of the zero-cross detection circuit. Referring to FIG. 13, the output width of the zero cross detection circuit also varies as the commercial AC power supply 1 varies. The time is shown on the horizontal axis, and the vertical axis is generated by comparing the waveforms W1 to W3 of the commercial AC power supply 1 with the dotted line L1 indicating the reference voltage Vref and the waveforms W1 to W3 described above in order from the top. Output waveforms WA1 to WA3 of the zero cross detection circuit are shown. Incidentally, any period of the waveform W1~W3 has a period _{T 0.}

  Specifically, for example, in the case of the commercial AC power supply 1 (low amplitude) indicated by the waveform W3, the waveform W3 is compared with the time until the commercial AC power supply 1 (standard) indicated by the waveform W2 becomes equal to or higher than the reference voltage. Since the time until the commercial AC power supply 1 (low amplitude) becomes equal to or higher than the reference voltage is slow, the output waveform WA3 of the corresponding zero-cross detection circuit is ON (High), and the waveform WA2 is ON (High). Slower than timing.

  Conversely, the timing until the commercial AC power source 1 (low amplitude) indicated by the waveform W3 becomes equal to or lower than the reference voltage Vref is compared to the timing until the commercial AC power source 1 (standard) indicated by the waveform W2 becomes equal to or lower than the reference voltage Vref. Therefore, the timing at which the output waveform WA3 of the corresponding zero-cross detection circuit is turned off (Low) is earlier than the timing at which the waveform WA2 is turned off (Low). Therefore, the pulse width of the ON (High) state indicated by the output waveform WA3 of the zero cross detection circuit is shorter than the pulse width of the corresponding output waveform WA2.

  In the case of the commercial AC power source 1 (amplitude high) indicated by the waveform W1, the commercial AC power source 1 (shown by the waveform W1 is compared with the time until the commercial AC power source 1 (standard) indicated by the waveform W2 becomes equal to or higher than the reference voltage. Since the time until the (high amplitude) becomes equal to or higher than the reference voltage is early, the output waveform WA1 of the corresponding zero-cross detection circuit is turned on (High) earlier than the timing when the waveform WA2 is turned on (High).

  Conversely, the timing until the commercial AC power source 1 (high amplitude) indicated by the waveform W1 becomes equal to or lower than the reference voltage Vref is compared to the timing until the commercial AC power source 1 (standard) indicated by the waveform W2 becomes equal to or lower than the reference voltage Vref. Therefore, the timing at which the output waveform WA1 of the corresponding zero-cross detection circuit becomes OFF (Low) is later than the timing at which the waveform WA2 becomes OFF (Low). Therefore, the pulse width of the ON (High) state indicated by the output waveform WA1 of the zero cross detection circuit is longer than the pulse width of the corresponding output waveform WA2.

  The relationship between the pulse width and the effective voltage value of the commercial AC power supply is stored in the microcomputer in advance, and the fluctuation of the effective voltage value of the commercial AC power supply can be detected based on the detected output clock width of the zero cross circuit. It becomes possible.

  The apparent power is calculated by using the voltage effective value of the commercial AC power source calculated above and the AC current effective value detected from the AC current detection circuit, and the active power is obtained by the same method described in the first to third embodiments. It is possible to calculate and estimate a power source power factor with higher accuracy.

[Embodiment 6]
In the sixth embodiment, when peak control control is performed using the power source power factor calculated in the first to fifth embodiments, the operation is continued while suppressing a decrease in product capability without applying a load to the electrical components. A control method will be described.

  Products that perform peak control control for electrical component protection and that can achieve sufficient functions even with a current lower than the component protection current value must have a margin for the component protection current value. In fact, there may be no problem even if a current larger than the peak control control current value is actually supplied.

  For example, in the case of an air conditioner, a model with a rated capacity of 2.2 kW and a model with a 2.5 kW may be produced by sharing parts and the like in order to reduce development power and reduce costs by common design.

  In this case, the same electrical component is used for the above two types, so the component protection current is the same, but the current for achieving the capability is smaller at 2.2 kW. For this reason, a product of 2.2 kW may set a peak control current threshold (Ipeak1) having a margin with respect to the component protection current.

  In some cases, the component protection current value (Ipeak2) is stored in advance in the storage unit 8 of the microcomputer A1 in FIG. 11 separately from the peak control current threshold.

  Further, the power source power factor of the rated voltage in the normal state is measured in advance by experiments or the like, and the relationship between the active power and the power source power factor is stored in the storage unit 8 of the microcomputer A1.

  FIG. 14 is an example showing the relationship between the active power and the power source power factor. Referring to FIG. 14, electric power factors 0.6, 0.7,..., 0.9, 0.9 are preset according to active powers 100, 200,. This relationship is stored in the storage unit 8 of the microcomputer A1. FIG. 15 is a diagram showing a correspondence relationship between the compressor speed and the power factor. Referring to FIG. 15, electric power factors of 0.6, 0.6,..., 0.9 are preset according to the compressor rotational speeds 500, 1000,. It is stored in the storage unit 8 of A1. As described above, the relationship between the compressor rotation speed and the power source power factor may be stored in the storage unit 8 without using the relationship between the active power and the power source power factor. In addition, a rated voltage is applied to the power source power factor at this time, and the state at this time is called a standard state.

  Further, a power factor error PFdeg for determining whether the power source power factor is in a bad state is also stored in advance in the storage unit 8 of the microcomputer A1. This PFdeg is kept constant regardless of the magnitude of the active power.

  Further, in order to determine whether or not the AC current effective value is close to the peak control current threshold (Ipeak1), the peak control area current error (Ipeak_th) is also stored in advance in the storage unit 8 of the microcomputer A1.

  Here, the microcomputer A1 reads out the various information described above, and the power factor calculated in the fourth to fifth embodiments is stored in the microcomputer (standard power factor-power factor error PFdeg). If the difference is smaller than the difference, it is determined that the power source power factor is bad.

  When the power source power factor is determined to be poor and the AC current effective value is a current value equal to or greater than the difference of (peak control current threshold (Ipeak1) −peak control area current error (Ipeak_th)), the peak control is performed. Peak control control is performed by replacing the current threshold (Ipeak1) with the component protection current value (Ipeak2).

  As a result, even when the compressor rotation speed is suppressed by peak control control, for example, when the evaporation side heat exchange atmosphere temperature is high (cycle load is high), it is possible to control with a slightly higher current value. As a result, it is possible to provide a more comfortable product by suppressing a decrease in product performance.

[Embodiment 7]
In the seventh embodiment, when the peak control control described in the sixth embodiment is performed using the power source power factor calculated in the first to fifth embodiments, the peak control current threshold is set to the normal peak control threshold again. The control method to return to will be described.

  In the microcomputer A1 of FIG. 11, the peak control current threshold value (Ipeak1) is replaced with the component protection current value by the control method of the sixth embodiment, and the calculated power source power factor is (power factor-power factor in the standard state). Either the error PFdeg) is greater than the difference, or the AC current effective value is smaller than the difference (peak control current threshold (Ipeak1) −peak control area current error (Ipeak_th)). When satisfied, the peak control current threshold is returned from the component protection current value (Ipeak2) to the normal peak control current threshold (Ipeak2), and the operation is continued.

  Thereby, in the case where the comfort is not impaired, it is possible to perform an energy saving operation while suppressing an excessive increase in capacity.

  In addition, although it demonstrated using microcomputer A1 in Embodiment 6, 7, you may use microcomputer A11, A21, A3, without limiting to this.

  Here, the operation flow of the sixth and seventh embodiments will be briefly described again with reference to the drawings. FIG. 16 is a flowchart for explaining the operation of the sixth embodiment. FIG. 17 is a flowchart for explaining the operation of the seventh embodiment.

  Referring to FIGS. 16 and 17, when power is supplied to the synchronous motor driving device of FIG. 1, the power factor is calculated as described in the first to fifth embodiments, and is built in microcomputer A1. It is stored in the storage unit 8 (FIG. 3). The microcomputer A1 (control unit) reads the stored power source power factor from the storage unit 8.

  Next, the microcomputer A1 reads the peak control threshold current (Ipeak1) and the component protection current value (Ipeak2) stored in advance in the storage unit 8 (step S2), and further, the active power and power source power factor (standard state). The relationship information (FIG. 14) is read (step S3).

  Further, the microcomputer A1 reads the power source power factor error PFdeg stored in advance in the storage unit 8 (step S4), and reads the peak control current error (Ipeak_th) (step S5).

  The microcomputer A1 sets a current value for peak control control based on the information described above. Specifically, the microcomputer A1 determines whether or not the calculated power source power factor is smaller than (power source power factor in the standard state−power source power factor error PFdeg) (step S6).

  When the calculated power source power factor is smaller than (power source power factor in the standard state−power source power factor error PFdeg) (step S6: YES), the AC current effective acquired from the AC current detection circuit 16 of FIG. It is determined whether or not the value is larger than (peak control current threshold (Ipeak1) −peak control current error (Ipeak_th)) (step S7).

  When the AC current effective value is larger than (peak control current threshold (Ipeak1) −peak control current error (Ipeak_th)) (step S7: YES), the component protection current value (Ipeak2) is selected as the peak control control current value. (Step S8).

  On the other hand, when the calculated power source power factor is larger than (power source power factor in standard state−power source power factor error PFdeg) (step S6: NO), or the AC current effective value is (peak control current threshold (Ipeak1) −peak control). When it is smaller than the current error (Ipeak_th) (step S7: NO), the peak control threshold current (Ipeak1) is selected as the peak control control current value (step S9).

  Next, in the state after the process of step S8, the microcomputer A1 determines whether the calculated power source power factor is larger than (power source power factor-power source power factor error PFdeg in the standard state) or whether the AC current effective value is ( It is determined whether or not it is smaller than the peak control current threshold (Ipeak1) −peak control current error (Ipeak_th) (step S11).

  In step S11, when either one is satisfied (step S11: YES), the peak control control current value is switched from the component protection current value (Ipeak2) to the peak control threshold current (Ipeak1) (step S12).

  On the other hand, when none of the conditions in step S11 is satisfied (step S11: NO), the component protection current value (Ipeak2) set in step S8 is used as the peak control control current value (step S13).

  In addition, although it determined in order of step S6 and step S7, you may determine step S6 after determining step S7.

  In addition, although it demonstrated using microcomputer A1 in Embodiment 6, 7, you may use microcomputer A11, A21, A3, without limiting to this.

Finally, the first to seventh embodiments will be summarized with reference to the drawings and the like.
As shown in FIGS. 1, 8, 11, and 12, the synchronous motor driving device according to the first and third to seventh embodiments includes an AC power supply 1 and a converter circuit that converts an AC voltage into a DC voltage and outputs the same 2, AC current detection circuits 16 and 23 for detecting an AC current installed between the AC power supply 1 and the converter circuit 2, and DC voltage detection circuits (Rdc 1 and Rdc 2) for detecting the output DC voltage of the converter circuit 2. And an inverter circuit 3 that converts a DC voltage into a variable frequency AC voltage and outputs the AC voltage to the synchronous motor 4, and DC current detection circuits 5 and 53 and an inverter circuit 3 provided between the converter circuit 2 and the inverter circuit 3. The microcomputer A1 includes microcomputers A1 and A21 to be controlled. The microcomputer A1 has a storage unit 8, an apparent power derived from an alternating current, and an output derived from an output direct current voltage. The converter circuit 2 includes a power source power factor estimating unit 6 that estimates a power source power factor based on electric power, and a PWM signal generating unit 7 that generates a PWM signal for converting a DC voltage into an AC voltage having a variable frequency. A rectifier circuit (DB, 212) that generates a rectified voltage from a power supply and a smoothing circuit (213, 214, C, C1, C2) that smoothes a DC voltage are included.

  Preferably, in the synchronous motor driving apparatus according to the first embodiment, as shown in FIGS. 1 and 3, the power source power factor estimation unit 6 is configured to output DC currents and output DC voltages from the DC current detection circuits 5 and 53. Based on the instantaneous power derived from each instantaneous value, the active power calculation unit 63 that calculates the first active power of the synchronous motor, and the proportionality constant for calculating the second power that is proportional to the first active power Is stored in the proportional constant storage unit 642, the total active power calculation unit 64 that calculates the third active power based on the first active power and the second power, the alternating current and the rating stored in advance. There is an apparent power calculation unit 651 that calculates the apparent power from the AC voltage, and a power source power factor calculation unit 65 that calculates the power factor based on the third active power and the apparent power.

  Preferably, in the synchronous motor drive device according to the third embodiment, as shown in FIGS. 8 and 10, the power source power factor estimation unit 6 </ b> A includes the output DC current and the output DC voltage from the DC current detection circuits 5 and 53. Based on the instantaneous power derived from each instantaneous value, the active power calculation unit 63 that calculates the first active power of the synchronous motor, and the proportionality constant for calculating the second power that is proportional to the first active power Is stored in the proportional constant storage unit 642, the total active power calculation unit 64 that calculates the third active power based on the first active power and the second power, the instantaneous value of the output DC voltage, and the output Based on the ripple period superimposed on the DC voltage and the first active power, the voltage RMS value calculation unit 641 that calculates the AC voltage RMS value, the output of the voltage RMS value calculation unit, and the AC current, Apparent power calculation unit 6 to calculate And 1A, based on a third active power and apparent power, having a power factor calculation unit 65 for calculating the power factor of the power supply.

  Preferably, the synchronous motor driving device according to Embodiment 4 changes the phase of the AC voltage of AC power supply 1 when the AC voltage of AC power supply 1 reaches a predetermined voltage value, as shown in FIGS. It further includes a voltage phase detection circuit 22 that detects and outputs a pulse signal having a pulse width corresponding to the detected phase. The converter circuit 2A includes a reactor 211 connected in series to the AC current detection circuit, and a reactor via the reactor. The microcomputer A1 further includes a short circuit 215 that short-circuits the AC voltage of the AC power supply, and the microcomputer A1 controls the operation of the short circuit based on the pulse signal.

  More preferably, in the synchronous motor driving apparatus of the fifth embodiment, as shown in FIGS. 13 to 15, the storage unit 8 stores in advance the relationship data between the pulse signal and the AC voltage, and the microcomputer A1 stores the relationship data. , And the relational data is compared with the output detected from the voltage phase detection circuit 22 to calculate the AC voltage of the AC power source 1 and the power source power factor.

  Moreover, as shown in FIGS. 6 and 7, the synchronous motor drive device according to the second embodiment includes an AC power source 1, a converter circuit 2 that converts an AC voltage into a DC voltage, and outputs the AC power source 1 and a converter. An alternating current detection circuit 16 for detecting an alternating current installed between the circuit 2 and a direct current voltage detection circuit (Rdc1, Rdc2) for detecting an output direct current voltage of the converter circuit 2; A plurality of inverter circuits 31 and 32 that convert to AC voltage and output to the plurality of synchronous motors 41 and 42, respectively, and a plurality of DC current detection circuits 51 provided between the converter circuit 2 and the plurality of inverter circuits 31 and 32. , 52 and a microcomputer A11 for controlling the plurality of inverter circuits 31, 32. The microcomputer A11 is derived from the storage unit 8 and the alternating current. A plurality of power source power factor estimators 6M and 6FM for estimating power source power factors of the plurality of synchronous motors 41 and 42 based on the apparent power and the effective power derived from the output DC voltage, and the plurality of synchronous motors 41 and 42, respectively. The converter circuit 2 includes a plurality of PWM signal generators 7M and 7FM that respectively generate PWM signals for converting the DC voltage of 42 into an AC voltage of variable frequency, and the converter circuit 2 generates a rectified voltage from an AC power supply. , 212 and smoothing circuits 213, 214, C, C1, C2 for smoothing the DC voltage, and each of the plurality of power source power factor estimators 6M, 6FM includes an output DC current from the DC current detection circuit and An active power calculation unit 63 that calculates the first active power of the synchronous motor based on the instantaneous power derived from each instantaneous value of the output DC voltage, and proportional to the first active power Based on the proportional constant storage unit 642 that stores the proportional constant for calculating the second power, and the first active power and the second power, the total active power calculation unit 64 that calculates the third active power. And an apparent power calculation unit 651 for calculating the apparent power based on the alternating current, the pre-stored rated alternating voltage and the alternating current, and the power supply power for calculating the power factor based on the third active power and the apparent power. A rate calculator 65 is included.

  Preferably, in the sixth embodiment, as shown in FIGS. 16 and 17, the storage unit 8 stores the reference power factor and the reference alternating current effective value in advance, and the microcomputers A1, A11, and A21 store The reference power source power factor and the reference alternating current effective value are read from the unit 8, and the output from the power source power factor calculating unit 65, 65M, 65FM is smaller than the reference power source power factor, and the alternating current detection circuits 16, 23 When the output from the reference AC current is larger than the effective value of the reference AC current, the voltage applied to the synchronous motor is reduced, and the peak control control is performed so that the output from the AC current detection circuits 16 and 23 does not exceed the predetermined current value. Change the current value used for.

  More preferably, the storage unit 8 further stores a component protection current value that can be received by a component used in the synchronous motor driving device and a peak control current threshold value for peak control control, and the reference power source power factor is The reference AC current effective value is set by the difference between the peak control current threshold value and the error current when the rated voltage is applied, and the microcomputer A1, A11 and A21 are peaks when the output from the power source power factor calculation units 65, 65M and 65FM is smaller than the reference power source power factor, and when the output from the AC current detection circuits 16 and 23 is larger than the reference AC current effective value. The threshold value of the current value used for control control is switched from the peak control current threshold value to the component protection current value.

  Preferably, in the seventh embodiment, as shown in FIGS. 16 and 17, the microcomputers A1, A11, and A21 are the cases where the peak control current threshold is set to the component protection current value, and the power source power factor When the outputs from the calculation units 65, 65M, and 65FM are larger than the reference power source power factor, the threshold value of the current value used for the peak control control is switched from the component protection current value to the peak control current threshold value.

  Preferably, in the seventh embodiment, as shown in FIGS. 16 and 17, the microcomputers A1, A11, and A21 are the cases where the peak control current threshold is set to the component protection current value, and the alternating current detection is performed. When the outputs from the circuits 16 and 23 are smaller than the reference alternating current effective value, the threshold value of the current value used for the peak control control is switched from the component protection current value to the peak control current threshold value.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 commercial AC power supply, 2, 2A converter circuit, 3, 3A, 31, 32, 351 inverter circuit, M4, M41, FM42 synchronous motor, 5, 51-53, 331 DC current detection circuit, 6, 6A, 6M, 6FM Power source power factor estimation unit, 7, 7M, 7FM PWM signal generation unit, 8 storage unit, 16, 23 AC current detection circuit, 22 zero cross detection unit (voltage phase detection circuit), A1, A11, A21, A3 microcomputer, 61 , 61M, 61FM Instantaneous current distribution unit, 62 Instantaneous power calculation unit, 63 Active power calculation unit, 64 Total active power calculation unit, 65, 65M, 65FM Power source power factor calculation unit, 211 Reactor, 212, DB Rectifier circuit, 213 214, C, C1, C2 Smoothing circuit, 215 short circuit, 216 transistor, 321 DC voltage detection circuit , R1 current detection resistor (shunt resistor), Rdc1, Rdc2 resistance.

Claims (10)

AC power supply,
A converter circuit for converting an AC voltage into a DC voltage and outputting it;
An AC current detection circuit for detecting an AC current installed between the AC power supply and the converter circuit;
A DC voltage detection circuit for detecting an output DC voltage of the converter circuit;
An inverter circuit that converts the DC voltage into an AC voltage of variable frequency and outputs it to a synchronous motor;
A direct current detection circuit provided between the converter circuit and the inverter circuit;
A control unit for controlling the inverter circuit,
The controller is
A storage unit;
A power source power factor estimator for estimating a power source power factor based on the apparent power derived from the alternating current and the active power derived from the output DC voltage;
A PWM signal generator that generates a PWM signal for converting the DC voltage into an AC voltage of variable frequency,
The converter circuit is
A rectifier circuit for generating a rectified voltage from the AC power supply;
A synchronous motor driving device including a smoothing circuit for smoothing the DC voltage. The power source power factor estimator is
An active power calculation unit that calculates a first active power of the synchronous motor based on an instantaneous power derived from an instantaneous value of each of the output DC current and the output DC voltage from the DC current detection circuit;
A proportionality constant storage for storing a proportionality constant for calculating the second power proportional to the first active power;
Based on the first active power and the second power, a total active power calculation unit for calculating a third active power;
An apparent power calculation unit for calculating the apparent power based on the alternating current and a pre-stored rated alternating voltage;
The synchronous motor drive device according to claim 1, further comprising a power source power factor calculation unit that calculates a power source power factor based on the third active power and the apparent power. The power source power factor estimator is
An active power calculation unit that calculates a first active power of the synchronous motor based on an instantaneous power derived from an instantaneous value of each of the output DC current and the output DC voltage from the DC current detection circuit;
A proportionality constant storage for storing a proportionality constant for calculating the second power proportional to the first active power;
Based on the first active power and the second power, a total active power calculation unit for calculating a third active power;
Based on the instantaneous value of the output DC voltage, the ripple period superimposed on the output DC voltage, and the first active power, a voltage effective value calculation unit that calculates an AC voltage effective value;
An apparent power calculation unit that calculates the apparent power based on the output of the voltage effective value calculation unit and the alternating current;
The synchronous motor drive device according to claim 1, further comprising a power source power factor calculation unit that calculates a power source power factor based on the third active power and the apparent power. The synchronous motor driving device is
A voltage phase detection circuit for detecting a phase of the AC voltage of the AC power supply when the AC voltage of the AC power supply reaches a predetermined voltage value and outputting a pulse signal having a pulse width corresponding to the detected phase; Prepared,
The converter circuit is
A reactor connected in series to the alternating current detection circuit;
Including a short circuit that short-circuits the AC voltage of the AC power supply through the reactor,
The synchronous motor driving apparatus according to claim 2, wherein the control unit controls an operation of the short circuit based on the pulse signal. The storage unit stores in advance relationship data between the pulse signal and the AC voltage,
The control unit reads the relation data, compares the relation data with an output detected from the voltage phase detection circuit, thereby calculating an AC voltage of the AC power source, and calculates a power source power factor. The synchronous motor drive device according to claim 4. AC power supply,
A converter circuit for converting an AC voltage into a DC voltage and outputting it;
An AC current detection circuit for detecting an AC current installed between the AC power supply and the converter circuit;
A DC voltage detection circuit for detecting an output DC voltage of the converter circuit;
A plurality of inverter circuits each of which converts the DC voltage into a variable frequency AC voltage and outputs the same to a plurality of synchronous motors;
A plurality of DC current detection circuits provided between the converter circuit and the plurality of inverter circuits;
A control unit for controlling the plurality of inverter circuits,
The controller is
A storage unit;
A plurality of power source power factor estimators for respectively estimating a power source power factor of the plurality of synchronous motors based on an apparent power derived from the AC current and an active power derived from the output DC voltage;
A plurality of PWM signal generators each generating a PWM signal for converting the DC voltage of the plurality of synchronous motors into an AC voltage of variable frequency,
The converter circuit is
A rectifier circuit for generating a rectified voltage from the AC power supply;
A smoothing circuit for smoothing the DC voltage,
Each of the plurality of power source power factor estimators is
An active power calculator that calculates a first active power of the synchronous motor based on an instantaneous power derived from an instantaneous value of each of the output DC current and the output DC voltage from the DC current detection circuit;
A proportionality constant storage for storing a proportionality constant for calculating the second power proportional to the first active power;
Based on the first active power and the second power, a total active power calculation unit for calculating a third active power;
An apparent power calculation unit for calculating the apparent power based on the alternating current, a pre-stored rated alternating voltage and the alternating current;
The synchronous motor drive device which has a power supply power factor calculation part which calculates a power supply power factor based on the 3rd effective power and the apparent power. The storage unit stores in advance a reference power source power factor and a reference alternating current effective value,
The controller is
Reading the reference power factor and the reference alternating current effective value from the storage unit,
When the output from the power source power factor calculation unit is smaller than the reference power source power factor and the output from the AC current detection circuit is larger than the reference AC current effective value,
The voltage applied to the synchronous motor is reduced, and the current value used for peak control control is changed so that the output from the AC current detection circuit does not exceed a predetermined current value. 2. The synchronous motor drive device according to item 1. The storage unit further stores a component protection current value that can be received by a component used in the synchronous motor driving device and a peak control current threshold for peak control control,
The reference power factor is set by the difference between the power factor and the power factor error when the rated voltage is applied,
The reference AC current effective value is set by the difference between the peak control current threshold and the error current when a rated voltage is applied,
The controller is
When the output from the power source power factor calculation unit is smaller than the reference power source power factor and the output from the AC current detection circuit is larger than the reference AC current effective value, the threshold value of the current value used for peak control control The synchronous motor driving device according to claim 7, wherein the motor is switched from the peak control current threshold value to the component protection current value. The controller is
When the peak control current threshold is set to the component protection current value, and the output from the power source power factor calculation unit is larger than the reference power source power factor, the threshold value of the current value used for peak control control The synchronous motor drive device according to claim 8, wherein the component protection current value is switched from the component protection current value to the peak control current threshold value. The controller is
When the peak control current threshold is set to the component protection current value and the output from the alternating current detection circuit is smaller than the reference alternating current effective value, the current value used for peak control control is The synchronous motor drive device according to claim 8, wherein the threshold value is switched from the component protection current value to the peak control current threshold value.

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