JP6413738B2 - Engine driven air conditioner - Google Patents

Description

  The present invention relates to a heat exchanger provided on a refrigerant circuit of an engine-driven air conditioner, a plurality of fans for supplying air to the heat exchanger, and a control for controlling the operation of an electric motor included in each of the plurality of fans. And an engine-driven air conditioner including the apparatus.

  A refrigerant circuit of an engine-driven air conditioner (for example, a gas heat pump air conditioner) is generally provided with a heat exchanger (for example, an indoor heat exchanger and an outdoor heat exchanger) that performs heat exchange between the refrigerant and air. It is done. Specifically, these heat exchangers exchange heat between the refrigerant flowing through the refrigerant circuit and the air supplied to the heat exchanger by the blower. The blower generally includes a fan (rotary blade) and an electric motor for driving the fan to rotate.

  In recent years, from the viewpoint of controlling the amount of air blown by a blower with high accuracy and high efficiency, an electric motor that operates in a PWM system using an inverter circuit (for example, a permanent magnet synchronous motor) is mainly employed as an electric motor used for the blower. Has been. Although this type of electric motor is excellent in controllability and efficiency, there is a case where electric corrosion (a phenomenon in which these members are damaged by discharge generated between members constituting the bearing) occurs in the bearing of the rotating shaft (output shaft). This electric corrosion may cause a decrease in the function of the bearing and the generation of abnormal noise, which in turn may shorten the service life of the air conditioner. Therefore, it is desirable to reduce the electric corrosion in the motor bearing as much as possible.

  For example, one of the conventional motors (hereinafter referred to as “conventional motor”) is used as an air supply source of an air shower, and the rolling elements (balls) of the motor bearings (rolling bearings) are made of ceramics which are insulating materials. Forming. As a result, the conventional electric motor suppresses electric discharge between the bearing rings (inner race and outer race) of the bearing and the rolling elements (ceramic balls), and reduces electric corrosion of the bearing (for example, Patent Documents). 1).

JP 2000-121115 A

(Problems to be solved by the invention)
The motor bearing needs to support a rotating shaft that rotates at high speed while maintaining high positional accuracy. For this reason, special steels (bearing steels) for bearings that are excellent in hardness, fatigue resistance, dimensional stability, and the like are generally used as materials constituting the motor bearings. Although it is possible to satisfy the above-mentioned characteristics required for motor bearings by using other materials (for example, ceramics conventionally employed in electric motors), it is generally high due to difficulty in material production and processing, etc. Manufacturing cost is required.

  In particular, since an electric motor used for a blower of an engine-driven air conditioner needs to rotationally drive a large fan, generally, it has a large-diameter rotating shaft and a large-sized rotating shaft compared with a conventional electric motor (motor for an air shower). In many cases, bearings are provided. As a result, when the motor bearing is formed of a material (ceramics or the like) different from the bearing steel, it is difficult not only to satisfy the above characteristics, but also a very high manufacturing cost is required. Therefore, it is desirable to reduce electrolytic corrosion without using a special insulating material or the like for the motor bearing.

  In view of the above problems, an object of the present invention is to reduce as much as possible electrolytic corrosion generated in a motor bearing used in a blower of an engine-driven air conditioner without using a special insulating material or the like for the bearing. The object is to provide a possible air conditioner.

(Means for solving the problem)
The engine-driven air conditioner of the present invention for achieving the above-described object is
"Heat exchanger" provided on the refrigerant circuit of the air conditioner,
A plurality of fans for supplying air to the heat exchanger, each of the plurality of fans having a motor and a motor that supports a rotating shaft for driving the fan with a bearing,
A control device that operates an inverter circuit that generates electric power supplied to each of the electric motors, wherein “the rotation of all or part of the electric motors while maintaining a state in which a total air flow amount by the plurality of air blowers satisfies a required air flow rate "Control device" capable of operating the inverter circuit so as to perform "electric corrosion reduction control to increase or decrease speed",
Is provided.

  According to the above configuration, an air conditioner configured such that “a plurality of blowers” “supplies air to the heat exchanger” (in other words, an air conditioner that satisfies the requested amount of air blown by the total amount of air blown by the plurality of air blowers). ), “A control device that operates the inverter circuit” is “electric corrosion reduction control that increases or decreases the rotational speed of all or part of the electric motor while maintaining the total amount of air blown by the plurality of fans satisfying the required amount of air blow”. Can be executed.

  Here, as a cause of the occurrence of electrolytic corrosion in the motor bearing, for example, the following matters can be cited. First, between the members constituting the bearing (for example, in the case of a rolling bearing, between the inner race and the roller and between the outer race and the roller) is separated by a lubricating oil film, so that a stray capacitance (parasitic) is established between the members. Capacity) is formed. On the other hand, it is known that electric charges are generated in a rotor of an electric motor due to switching of the electric motor by an inverter circuit. This electric charge moves to the bearing via the rotating shaft of the electric motor and is accumulated in the above-described stray capacitance. Then, when the amount of accumulated charge (in other words, the potential difference between the members) exceeds the dielectric breakdown voltage determined by the thickness of the lubricating oil film, a discharge that conducts between the members occurs. Due to heat generated during the discharge, electrolytic corrosion occurs.

  On the other hand, according to experiments and considerations conducted by the inventor of the present invention, compared with the case where the rotation speed of the motor (the number of rotations per unit time of the rotating shaft of the motor) is maintained at a constant value A, the motor It has been clarified that electrolytic corrosion is less likely to occur in the case where the rotational speed of is fluctuating (for example, when the value fluctuates periodically between values A + B and A−B). One reason for this is that due to the inertia of the lubricating oil and the like, the average amount of lubricating oil taken in between the bearing members in the latter case (that is, the average thickness of the lubricating oil film) is greater than the former case. It is considered that the average value of the breakdown voltage increases.

  Therefore, the air conditioner of the present invention performs the “electric corrosion reduction control” as necessary, while maintaining the function as a blower without changing the material of the bearing of the electric motor (the required blown amount is reduced). It is possible to reduce electric corrosion while satisfying.

  Therefore, the air conditioner of the present invention can reduce the electric corrosion generated in the motor bearing used for the blower of the engine-driven air conditioner as much as possible without using a special insulating material or the like for the bearing. .

  By the way, the “heat exchanger” may be a heat exchanger provided on the refrigerant circuit of the air conditioner, and the type thereof is not particularly limited. For example, examples of the heat exchanger include a heat exchanger used for an outdoor unit of an air conditioner and a heat exchanger used for an indoor unit.

  The “motor” may be an electric motor driven by a control device having an inverter circuit (for example, driven by a PWM method), and the type thereof is not particularly limited. For example, a synchronous motor (such as SPM and IPM) and an induction motor can be used as the motor.

  The “required air flow” is a required air amount supplied to the heat exchanger by the blower. For example, the air conditioning load of the air conditioner, the pressure of the refrigerant at a predetermined position on the refrigerant circuit, the compressor provided in the air conditioner The refrigerant discharge pressure and the compressor power of the compressor can be determined. Specifically, for example, the required air volume can be determined so as to increase as the air conditioning load of the air conditioner increases.

  The rotational speed increase / decrease method in the “electric corrosion reduction control” may be determined based on the number of blowers (number of electric motors) and the rotational speed during the period when the electrolytic corrosion reduction control is not performed. Not.

For example, as an example of a method for increasing or decreasing the rotational speed in the electric corrosion reduction control, the control device
When the electric corrosion reduction control is started in the case where the inverter circuit is operated so that the amount of air blown from each of the plurality of blowers is the same,
The inverter circuit may be operated so as to increase / decrease all the rotation speeds of the electric motor to a waveform having the same amplitude and the same period.

  When a plurality of blowers are provided for a heat exchanger of an air conditioner, generally, the same blower is employed as the plurality of blowers. When the same blower is employed, the blowers are normally controlled so that “the air flow rate of each of the plurality of blowers is the same”. Therefore, as in the above configuration, in the electric corrosion reduction control, if the rotational speed of “all of the motors” is “increased or decreased to a wave shape with the same amplitude and the same period”, the degree of electric corrosion of all the electric motors is approximately the same. Can be. As a result, the degree of electrolytic corrosion of some of the electric motors is prevented from protruding and deteriorated, and the service life of the plurality of blowers as a whole can be extended.

  The timing for executing the “electric corrosion reduction control” and the length of the execution time may be determined in consideration of the degree of required electric corrosion reduction and the like, and are not particularly limited. For example, the electric corrosion reduction control may be always performed during the operation of the air conditioner, or may be performed at a timing and an execution time (in other words, a frequency) in consideration of the operation state of each blower.

For example, as an example of the execution frequency of the electric corrosion reduction control, the control device
The frequency of performing the electric corrosion reduction control may be configured to be determined based on the total blowing amount.

  As described above, the rotational speed of the electric motor affects the thickness of the lubricating oil film and also affects the likelihood of the occurrence of electrolytic corrosion. Specifically, according to the experiments of the inventor and the like, it is clear that the degree of electrolytic corrosion (for example, the number of discharges per unit time) increases as the rotational speed of the electric motor (that is, the amount of air blown from the blower) increases. Became. Therefore, if the frequency of the electric corrosion reduction control is determined based on the total amount of air blown by the plurality of fans (that is, the average rotational speed of the plurality of motors), the electric corrosion reduction control can be performed at an appropriate timing and execution time. it can.

It is a mimetic diagram showing an engine drive type air harmony machine concerning an embodiment of the present invention. It is a schematic diagram for demonstrating in detail the outdoor heat exchanger which the air conditioner of FIG. 1 has. It is the flowchart which showed the routine which the control apparatus of the air conditioner which concerns on embodiment of this invention performs. It is a schematic diagram showing the relationship (during a normal driving | operation) with the rotational speed of the electric motor of the air blower provided in the outdoor heat exchanger which the air conditioner which concerns on embodiment of this invention has, and time passage. It is a schematic diagram showing the relationship between the rotational speed of the electric motor of the air blower provided in the outdoor heat exchanger which the air conditioner which concerns on embodiment of this invention has, and time passage (during execution of electrolytic corrosion reduction control). It is a schematic diagram showing the relationship between the rotational speed of the electric motor of the air blower provided in the outdoor heat exchanger which the air conditioner which concerns on other embodiment of this invention has, and time passage (during execution of electric corrosion reduction control). is there.

<Outline of device>
Hereinafter, a schematic configuration of an air conditioner (hereinafter referred to as “implementation conditioner”) according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 shows a schematic configuration of the implementation harmony machine 100. The implementation harmony machine 100 is provided with the refrigerant circuit 200, the drive system 300 for operating the refrigerant circuit 200, and the electronic control device 400 that controls the operation of the implementation harmony machine 100.

  The refrigerant circuit 200 includes a compressor 201 that compresses the refrigerant using the driving force output from the drive system 300, and an oil separator that collects the lubricating oil mixed in the refrigerant discharged from the compressor 201 and returns the lubricating oil to the compressor 201. 202, a four-way switching valve 203 that guides the refrigerant that has passed through the oil separator 202 in a direction according to the operation mode (cooling operation or heating operation) of the implementation harmonic machine 100, and performs heat exchange between the outdoor air and the refrigerant ( For example, the refrigerant that flows out of the four-way selector valve 203 flows during cooling operation) The outdoor heat exchanger 204, the two blowers 205 and 206 that send air to the outdoor heat exchanger 204, and expand the refrigerant to reduce the pressure and temperature. Electronic expansion valve 207, indoor heat exchanger 208 for exchanging heat between indoor air and refrigerant, refrigerant air To perform separation (separate only the gas refrigerant from the gas-liquid two-phase flow refrigerant flowing in from the upstream side and flow it downstream), and to supply the exhaust heat of the drive system 300 to the outdoor heat exchanger 204 The sub heat exchanger 210 is provided.

  More specifically, as shown in FIG. 2, the outdoor heat exchanger 204 is provided on a housing 204a, heat exchanger bodies 204b and 204c attached to a side surface of the housing 204a, and an outer side wall of the housing 204a. A blower power supply 204d is provided. Further, the blower 205 attached to the outdoor heat exchanger 204 includes a fan 205a, a bearing 205b that supports a rotating shaft for driving the fan 205a, and an electric motor 205c that rotates the fan 205a via the bearing 205b. doing. Similarly, the blower 206 includes a fan 206a, a bearing 206b that supports a rotating shaft for driving the fan 206a, and an electric motor 206c that rotationally drives the fan 206a via the bearing 206b.

  The blower power supply 204d incorporates an inverter circuit (an inverter circuit for the electric motor 205c and an inverter circuit for the electric motor 206c) and is connected to an external power supply (not shown). The blower power supply 204d operates the inverter circuit according to an instruction from the electronic control device 400, converts the power supplied from the external power supply according to the PWM method, and then supplies the power to the motor 205c and the motor 206c through the wire harnesses 204e and 204f. Thus, the blower power supply 204d (in other words, the electronic control device 400) can operate each of the electric motor 205c and the electric motor 206c at a desired rotation speed.

  When the electric motor 205c and the electric motor 206c operate, the fan 205a and the fan 206a rotate. As a result, air flows from the outside of the housing 204a and passes through the heat exchanger bodies 204b and 204c and then discharged from the fans 205a and 206a, as in the air flows (Af1 and Af2) indicated by the broken lines in the figure. A flow is formed. In the figure, the air blowers 205 and 206 and the air flow (Af1 and Af2) have a one-to-one correspondence. However, this is merely an expression for convenience, and only one of the air blower 205 and the air blower 206 is activated. An air flow passes through the two heat exchanger bodies. As will be described later, the electric motor 205c and the electric motor 206c are operated so that the total amount (total airflow amount) of the respective airflow rates Af1 and Af2 satisfies the required airflow rate Areq. In other words, the required air flow rate Areq is determined as the total amount of air passing through the two heat exchanger bodies 204b and 204c.

  Referring to FIG. 1 again, the drive system 300 recovers the thermal energy of the engine 301 that uses city gas and propane gas as fuel, the exhaust pipe 302 that exhausts the exhaust gas from the engine 301, and the exhaust gas that passes through the exhaust pipe 302. An exhaust gas heat exchanger 303, a drain drainer 304 provided in an exhaust pipe on the downstream side of the exhaust gas heat exchanger 303, a silencer 305 that silences exhaust gas after passing through the drain drainer 304 and releases it to the atmosphere, A drain drain pipe 306 through which drain water discharged from the drain drain 304 passes, a neutralizer 307 to neutralize the drain water, and a cooling water pipe 308 connecting the exhaust gas heat exchanger 303 and the sub heat exchanger 210. ,have. Note that the engine exhaust heat is supplied to the refrigerant circuit 200 (specifically, the outdoor heat exchanger 204) by the cooling water flowing in the cooling water pipe 308.

  The electronic control device 400 is an electronic circuit mainly composed of a known microcomputer including a CPU, a ROM, a RAM, and the like. The CPU of the electric control device 400 transmits an instruction signal to the four-way switching valve 203, the outdoor heat exchanger 204 (specifically, the blower power supply 204d), the electronic expansion valve 207, the indoor heat exchanger 208, the engine 301, and the like. In addition, it is configured to receive a signal output from the indoor heat exchanger 208 or the like.

  The above is the outline of the implementation harmony machine 100.

<Operation of the device>
With reference to FIG. 3, the actual operation of the implementation harmony machine will be described. In the implementation harmony machine, the CPU (hereinafter simply referred to as “CPU”) of the electronic control device 400 executes the “blower control” routine shown in FIG. 3, and the total blown amount of the blower 205 and the blower 206 is the required blown amount. The blower 205 and the blower 206 are controlled so as to satisfy. Furthermore, the CPU executes “electric corrosion reduction control” for increasing / decreasing the rotational speeds of the blower 205 and the blower 206 while maintaining the state where the total blown amount satisfies the requested blown amount as necessary.

  Specifically, the CPU repeatedly executes the routine of FIG. 3 every time a predetermined time has elapsed. When starting the processing of this routine at a predetermined time, the CPU proceeds from step 300 to step 305. In step 305, the CPU acquires the air conditioning load L of the implementation harmony machine 100 at the current time. The air conditioning load L is acquired based on, for example, a difference between a target temperature in the room where the indoor heat exchanger 208 is provided and an actual temperature in the room (which can be acquired by a temperature sensor or the like (not shown)). .

  Next, the CPU proceeds to step 310. In step 310, the CPU determines the current required air flow rate Areq of the outdoor heat exchanger 204 based on the air conditioning load L. Specifically, the requested airflow rate Areq is determined by applying the current air conditioning load L to a predetermined “relationship between the requested airflow rate Areq and the air conditioning load L” (MapAreq). The required air flow rate Areq is determined so that the required air flow rate increases as the air conditioning load L increases.

  Next, the CPU proceeds to step 315. In step 315, the CPU determines the blower amount of each of the blower 205 and the blower 206 based on the requested blower amount Areq. Specifically, by applying the current requested airflow rate Areq to a predetermined “relationship between the airflow rate Af1 of the blower 205, the airflow amount Af2 of the air blower 206, and the requested airflow rate Areq” (MapAf). The air flow Af1 of the blower 205 and the air flow Af2 of the blower 206 are determined. However, the blowing amount Af1 and the blowing amount Af2 are determined so that the sum (total blowing amount) of them coincides with the requested blowing amount Areq.

  Next, the CPU proceeds to step 320. In step 320, the CPU determines an instruction signal (signal wave) for operating the electric motors 205c and 206c in accordance with the concept of PWM control. Specifically, the CPU determines a signal wave Es1 for controlling the electric motor 205c of the blower 205 so that the blower 205 supplies the air flow of the blown amount Af1 to the outdoor heat exchanger 204. Similarly, in step 320, the CPU determines a signal wave Es <b> 2 for controlling the electric motor 206 c of the blower 206 so that the blower 206 supplies an air flow of the blown amount Af <b> 2 to the outdoor heat exchanger 204.

  The signal wave Es1 and the signal wave Es2 are instruction signals for operating the inverter circuit of the blower power supply 204d, and can be described in the form of “Es = αsinωt” using a predetermined wavelength α and frequency ω, for example. In this example, the carrier frequency (carrier frequency) in the inverter circuit is a predetermined fixed value.

  Specifically, the signal waves Es1 and Es2 in this example are “when the inverter circuit of the blower power supply 204d is driven by these signal waves, the electric motor 205c and the electric motor 206c have the same constant rotational speed as shown in FIG. Rotate with Na ". In FIG. 4, for the sake of convenience, the rotational speed of the electric motor 205c and the rotational speed of the electric motor 206c are described so as to be slightly different from each other, but they are actually the same rotational speed.

  Referring to FIG. 3 again, the CPU proceeds to step 325 after determining each signal wave. In step 325, the CPU determines whether or not to execute electric corrosion reduction control at the current time. Specifically, in this step, the CPU, in this step, the total blown amount of the blower 205 and the blower 206 (= Af1 + Af2), the elapsed time from the previous execution of the electric corrosion reduction control, and the rotation of the electric motor 205c and the electric motor 206c. Based on the upper limit value and the lower limit value of the speed, it is determined whether or not to perform the electrolytic corrosion reduction control.

  For example, if the CPU determines not to execute the electric corrosion reduction control at the current time, the CPU determines “No” in step 325 and proceeds to step 330. In step 330, the CPU gives an instruction to the blower power supply 204d so that the electric power based on the signal wave Es1 is supplied to the blower 205, and the blower power supply 204d is supplied with the electric power based on the signal wave Es2 to the blower 206. Give instructions. The blower power supply 204d operates an inverter circuit (an inverter circuit for the electric motor 205c and an inverter circuit for the electric motor 206c) based on these instructions, and supplies power to the blower 205 and the blower 206. As a result, as shown in FIG. 4, the blower 205 and the blower 206 rotate at a constant rotational speed Na.

  On the other hand, if it is determined that the electric corrosion reduction control is to be executed at the present time, the CPU determines “Yes” in step 325 and proceeds to step 335. In step 335, the CPU converts the signal wave Es1 and the signal wave Es2 into a signal wave for executing electrolytic corrosion reduction control. Then, the CPU updates (overwrites) the signal waves Es1 and Es2 with the converted signal waves.

  Specifically, the CPU converts the signal wave Es1 by applying the signal wave Es1 to the predetermined conversion function FuncM1, and converts the signal wave Es2 by applying the signal wave Es2 to the predetermined conversion function FuncM2. To do. As shown in FIG. 5, the conversion function FuncM1 converts the signal wave Es1 so that the rotation speed of the electric motor 205c increases or decreases in a sin wave shape (amplitude ΔN, frequency f) with time. Furthermore, the conversion function FuncM2 converts the signal wave Es2 so that the rotational speed of the electric motor 206c increases or decreases in a sin wave shape (amplitude ΔN, frequency f) as time elapses. Further, the conversion function FuncM1 and the conversion function FuncM2 convert the signal wave Es1 and the signal wave Es2 so that the phases of the sin waves are different by a half wavelength. In addition, the conversion function FuncM1 and the conversion function FuncM2 convert the signal wave Es1 and the signal wave Es2 so as to maintain a state in which the total blown amount of the blower 205 and the blower 206 satisfies the required blown amount Areq.

  Referring to FIG. 3 again, after converting the signal waves Es1 and Es2, the CPU proceeds to step 330 and instructs the blower power supply 204d to supply power to the blower 205 based on the signal wave Es1 (after conversion). An instruction is given to the blower power supply 204d so that the electric power based on the signal wave Es2 (after conversion) is supplied to the blower 206. As a result, as shown in FIG. 5, the rotational speeds of the electric motor 205c and the electric motor 206c are increased or decreased in a sin wave shape having the same amplitude ΔN and the same period T / f (T is a constant).

  By increasing or decreasing the rotational speed, the degree of electrolytic corrosion generated in the bearing 205b and the bearing 206b is reduced as compared with the case where the electric motor 205c and the electric motor 206c are operated as shown in FIG. One reason for this is that due to the inertia of the lubricating oil and the like, the average amount of lubricating oil taken in between the bearing members (that is, the average thickness of the lubricating oil film) is greater in the case of FIG. And the average value of the dielectric breakdown voltage is increased.

  Thereafter, the CPU proceeds to step 395 to end the present routine tentatively.

  As explained above, the implementation harmony machine performs electric corrosion reduction control (increase / decrease the rotational speed of the motors while maintaining the state where the total blown amount by the blower 205 and the blower 206 satisfies the required blown amount Areq as necessary ( 5), the inverter circuit of the blower power supply 204d is operated. Thereby, the electrolytic corrosion which arises in the bearings 205b and 206b of the electric motor used for the air blower of the implementation harmony machine 100 can be reduced as much as possible.

<Other aspects>
The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention.

  For example, the implementation harmony machine is configured to blow an air flow of the required air supply amount Areq to the outdoor heat exchanger 204 using two blowers 205 and 206. However, the air conditioner of the present invention may be configured to satisfy the required air volume using three or more fans. When three or more blowers are used, it is not always necessary to increase or decrease the rotation speeds of all the blowers in the electronic control unit, but only the rotation speeds of some of the blowers (in principle, two or more blowers). It may be configured to be increased or decreased.

  Furthermore, the implementation harmony machine performs electric corrosion reduction control so as to increase or decrease the rotational speeds of the two electric motors 205c and 206c in a sin wave shape (see FIG. 5). However, the air conditioner of the present invention does not necessarily need to increase or decrease the rotation speed of the electric motors 205c and 206c in a sin wave shape, and may increase or decrease the rotation speed of the electric motor in a triangular wave shape, for example, as shown in FIG. That is, the increase / decrease mode of the rotation speed of the electric motor when executing the electronic control device is not particularly limited.

DESCRIPTION OF SYMBOLS 100 ... Engine-driven air conditioner, 200 ... Refrigerant circuit, 205, 206 ... Blower, 204 ... Outdoor heat exchanger, 205a, 206a ... Fan, 205b, 206b ... Bearing, 205c, 206c ... Electric motor, 204d ... Blower power supply, 400 ... Electronic control unit

Claims (3)

A heat exchanger provided on the refrigerant circuit of the engine-driven air conditioner;
A plurality of blowers for supplying air to the heat exchanger, each of the plurality of blowers having a fan and a motor that supports a rotating shaft for driving the fan by a bearing; and
A control device that operates an inverter circuit that generates electric power supplied to each of the electric motors, wherein a rotational speed of all or part of the electric motors is maintained while maintaining a state in which a total air blowing amount by the plurality of fans satisfies a required air blowing amount. A controller capable of operating the inverter circuit so as to perform electric corrosion reduction control to increase or decrease
Engine-driven air conditioner equipped with In the air conditioner according to claim 1,
The control device is
When the electric corrosion reduction control is started in the case where the inverter circuit is operated so that the amount of air blown from each of the plurality of blowers is the same,
Actuating the inverter circuit so as to increase or decrease all the rotational speeds of the electric motor to the same amplitude and the waveform of the same period;
Engine-driven air conditioner. In the air conditioner according to claim 1 or 2,
The control device is
The frequency of performing the electric corrosion reduction control is determined based on the total blowing amount.
Engine-driven air conditioner.

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