JP2009214784A - Control device for electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an electric compressor capable of improving both of silence and efficiency required corresponding to a vehicle state. <P>SOLUTION: A control circuit 7 for the electric compressor includes a required silence degree determination section 7a that determines a required silence degree score corresponding to a vehicle state, and controls a PWM carrier frequency and edge steepness of a pulse based on the required silence degree score. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of control devices for electric compressors.

In Patent Document 1, the PWM carrier frequency for pulse width modulation (PWM) control and the frequency of the inverter driving the electric compressor are set for the purpose of achieving both efficiency (reduction of power loss) and quietness (reduction of noise). A technique for changing the edge steepness of a pulse is disclosed.
JP 2001-352786 A

  In Patent Document 1, since only the temperature condition of the inverter is taken into consideration and the vehicle state is not taken into consideration, the required quietness changes according to the vehicle state, but the quietness and the efficiency are compatible. I can't.

  The objective of this invention is providing the control apparatus of the electric compressor which can aim at coexistence with the silence required according to a vehicle state, and efficiency.

  In order to achieve the above object, according to the present invention, at least one of the carrier frequency of pulse width modulation and the edge steepness of a pulse is controlled based on the required quietness corresponding to the vehicle state.

  Therefore, in the present invention, since at least one of the carrier frequency of pulse width modulation and the edge steepness of the pulse is changed based on the required quietness according to the vehicle state, the required quietness according to the vehicle state. However, the required quietness and efficiency can both be achieved.

  Hereinafter, the best mode for realizing the control device for an electric compressor of the present invention will be described based on examples.

First, the configuration will be described.
[Configuration of air conditioner]
FIG. 1 is a configuration diagram of an air conditioner for a hybrid vehicle (HEV) to which the control device for the electric compressor according to the first embodiment is applied. The hybrid vehicle of Example 1 is a vehicle that travels using an engine and an electric motor as drive sources.
The air conditioner according to the first embodiment includes a refrigeration cycle in which a compressor 1, a cooling condenser 2, an expansion valve 3, and an evaporator 4 are connected by piping and a refrigerant is sealed therein.

  The compressor 1 is driven by a U-phase, V-phase, and W-phase three-phase AC synchronous motor (hereinafter simply referred to as a motor) 5 and encloses and compresses the low-temperature and low-pressure gas refrigerant evaporated by the evaporator 4 at the time of driving. Then, the high-temperature and high-pressure gas refrigerant is pumped to the cooling condenser 2, and the refrigerant is circulated repeatedly through the cooling condenser 2 and the evaporator 4. The cooling condenser 2 cools and condenses the high-temperature and high-pressure gas refrigerant sent from the compressor 1 by heat exchange with cooling air supplied by a condenser fan (not shown).

  A liquid tank (not shown) is interposed between the cooling condenser 2 and the expansion valve 3. The liquid tank gas-liquid separates the refrigerant liquefied by the cooling condenser 2 to temporarily store the liquid refrigerant, and sends only the liquid refrigerant to the expansion valve 3. In the case of the temperature type expansion valve 3 generally used, the medium temperature and high pressure liquid refrigerant that has passed through the liquid tank is expanded under reduced pressure to form a low temperature and low pressure mist refrigerant, and the refrigerant temperature downstream of the evaporator The refrigerant flow rate is adjusted so that the evaporation state of the refrigerant has an appropriate degree of superheat at the evaporator outlet by feedback of a temperature sensing cylinder (not shown) that detects the above.

  The evaporator 4 evaporates the mist refrigerant that has been liquefied by the cooling condenser 2 and has been cooled to low temperature and low pressure by the expansion valve 3, and flows the air sent by a blower fan (not shown) to the outside to exchange heat with the mist refrigerant. As a result, the air blown into the passenger compartment is cooled and simultaneously dehumidified.

  The motor 5 is driven by the three-phase alternating current output from the inverter 6, and the inverter 6 is driven by the motor 5 in accordance with a pulse width modulation (hereinafter referred to as PWM) command signal generated by the electric compressor control circuit (inverter control means) 7. Output voltage. The electric compressor control circuit 7 generates a PWM command signal based on a control command from the air conditioner controller 8. Since the compressor 1, the motor 5, the inverter 6, and the electric compressor control circuit 7 are integrated, they are collectively referred to as an electric compressor A.

The air conditioner controller 8 includes an input device 8a, a room temperature sensor 8b, and an air conditioner control circuit 8c.
The input device 8a is used by the occupant to set a desired vehicle interior temperature, and outputs the set temperature to the air conditioner control circuit 8c. The room temperature sensor 8b detects the temperature in the passenger compartment and outputs it to the air conditioner control circuit 8c. The air conditioner control circuit 8c generates a control command (the number of rotations of the motor 5) that eliminates the difference between the set temperature and the passenger compartment temperature in consideration of the vehicle information (vehicle state) and outputs the control command to the electric compressor control circuit 7. To do. In the first embodiment, vehicle speed and engine speed are read as vehicle information.

[Inverter circuit configuration]
FIG. 2 is a circuit configuration diagram of the inverter 6.
The inverter 6 is a voltage type PWM inverter that generates three-phase AC power for driving the motor from DC power applied from a battery (not shown) and applies the motor 5. In FIG. 2, only the U phase is illustrated for the sake of explanation and simplification, but the V phase and the W phase are the same as the U phase.

  The inverter 6 includes two IGBTs (Insulated Gate Bipolar Transistors) 11 and 12 and diodes 13 and 14 connected in antiparallel to the IGBTs 11 and 12, respectively. The upper IGBT 11 and the lower IGBT 12 are connected in series, and the IGBT series circuit is connected in parallel with the IGBT driver 15. Each IGBT series circuit constitutes a circuit for three arms corresponding to each phase (U, V, W) with three-phase AC power for driving the motor 5. In each arm, the upper IGBT 11 and the upper diode 13 constitute an upstream (upper) arm, and the lower IGBT 12 and the lower diode 14 constitute a downstream (lower) arm.

  Both IGBTs 11 and 12 are PWM-controlled by the IGBT driver 15 to generate three-phase AC power for driving the motor. Based on the PWM command signal input from the electric compressor control circuit 7, the IGBT driver 15 turns on and off the IGBTs 11 and 12 at desired timings, thereby driving the motor 5 in an arbitrary state. The three-phase AC drive power having the characteristics (voltage, frequency, etc.) is generated.

  In the upper arm and the lower arm, an edge steepness switch 16 is interposed between the IGBT driver 15 and the IGBTs 11 and 12, respectively. The edge steepness switch 16 includes three low-pass filters 16a, 16b, 16c and a switch 16d connected in parallel. The first filter 16a has a larger time constant than the second filter 16b, and the second filter 16b has a larger time constant than the third filter 16c. Therefore, the magnitude relationship between the time constants is as follows: first filter 16a> second filter 16b> third filter 16c.

The switch 16 d selectively switches the connection between the filters 16 a to 16 c and the IGBT 11 and IGBT 12 according to the slope control signal from the electric compressor control circuit 7. In FIG. 3, (a) is the pulse waveform when the first filter is selected, (b) is the pulse waveform when the second filter is selected, and (c) is the pulse waveform when the third filter is selected. The relationship is (c)>(b)> (a).
In the upper arm, a gate voltage amplification circuit 17 is interposed between the edge steepness switch 16 and the IGBT driver 15 to amplify the gate input of the upper IGBT 11.

  The electric compressor control circuit 7 includes a required quietness determination unit (required quietness determination means) 7a. The required quietness determination unit 7a calculates a required quietness level that is a level of quietness required in the current vehicle state from the vehicle information. The electric compressor control circuit 7 outputs a command for changing the carrier frequency of PWM control to the IGBT driver 15 based on the calculated required quietness, and switches a slope control signal for changing the edge steepness. To 16d.

[Electric compressor load level judgment control process]
FIG. 4 is a flowchart of the flow of the electric compressor load level determination control process executed by the electric compressor control circuit 7 of the first embodiment, and each step will be described below. This control process is started by inputting an air conditioner operation command.

  In step S1, a difference ΔT between the passenger compartment temperature detected by the room temperature sensor 8b and the set temperature input to the input device 8a is calculated, and the process proceeds to step S2.

  In step S2, it is determined whether the temperature difference ΔT is 3 ° C. or less. If YES, the process proceeds to step S5. If NO, the process proceeds to step S3.

  In step S3, it is determined whether or not the temperature difference ΔT is within a range of 4 ° C. to 10 ° C. If YES, the process proceeds to step S6. If NO, the process proceeds to step S4.

  In step S4, it is determined whether or not the temperature difference ΔT is within a range of 11 ° C. to 15 ° C. If YES, the process proceeds to step S7, and if NO, the process proceeds to step S8.

  In step S5, it is determined that the load operation of the electric compressor A is a minute load operation (load level 1), and the process proceeds to step S9. In the case of a minute load operation, the rotation speed of the motor 5 is set to 500 rpm.

  In step S6, it is determined that the load operation of the electric compressor A is a small load operation (load level 2), and the process proceeds to step S9. In the case of a small load operation, the rotation speed of the motor 5 is set within a range of 600 to 2,000 rpm.

  In step S7, it is determined that the load operation of the electric compressor A is a medium load operation (load level 3), and the process proceeds to step S9. In the case of medium load operation, the rotational speed of the motor 5 is set within a range of 2,000 to 4,000 rpm.

  In step S8, it is determined that the load operation of the electric compressor A is a high load operation (load level 4), and the process proceeds to step S9. In the case of high load operation, the rotation speed of the motor 5 is set within a range of 4,000 to 6,000 rpm.

  In step S9, it is determined whether or not an air conditioner stop command is output. If YES, this control is terminated, and if NO, the process proceeds to step S1.

[Pulse change control processing]
FIGS. 5-8 is a flowchart which shows the flow of the pulse change control process of PWM control performed with the electric compressor control circuit 7 of Example 1, and demonstrates each step hereafter.

(Small load operation)
FIG. 5 is used at the time of a minute load operation.
In step S11, the required quietness level determination unit 7a calculates the required quietness score, and the process proceeds to step S12.

FIG. 9 is a map for setting the required quietness score. The required quietness is obtained by adding the required quietness score according to the engine speed and the required quietness score according to the vehicle speed (vehicle speed). The required quietness score indicates that the required quietness is higher as the value is smaller. The required quietness score according to the engine speed is “1” at 0 to 1,000 rpm, and “2” at 1,001 to 2,000 rpm. , "3" at 2,001 to 3,000rpm, "4" at 3,001rpm or more. The required quietness score according to the vehicle speed is "1" at 0-9km / h, "2" at 10-40km / h, "3" at 41-80km / h, "4" at 81km / h or higher .
Therefore, the final required quietness score obtained by adding the required quietness score according to the engine speed and the required quietness score according to the vehicle speed is set in the range of “1” to “8”.

  In step S12, it is determined whether or not the required quietness score is 2 or less. If YES, the process proceeds to step S15. If NO, the process proceeds to step S13.

  In step S13, it is determined whether or not the required quietness score is 3 or 4. If YES, the process proceeds to step S16. If NO, the process proceeds to step S14.

  In step S14, it is determined whether or not the required quietness score is 5 or 6. If YES, the process proceeds to step S17. If NO, the process proceeds to step S18.

  In step S15, since the compressor (motor) load is small and the required quietness is high, the carrier frequency is set to 20 kHz, the edge steepness is set to a large time constant, the motor rotation speed is set to 500 rpm, and the process proceeds to step S19. . In the first embodiment, the carrier frequency and the edge steepness are set based on the maps shown in FIGS. In step S15, since the load level is 1 and the required quietness score is 2 or less, the carrier frequency is 20 kHz from FIG. 10, and the edge steepness is a large time constant from FIG.

  In step S16, since the compressor load is small and the required quietness is not high, the carrier frequency is set to 15 kHz, the edge steepness is set to a time constant, the motor rotation speed is set to 500 rpm, and the process proceeds to step S19.

  In step S17, since the compressor load is small and the required quietness is low, the carrier frequency is set to 10 kHz, the edge steepness is set to a time constant, the motor rotation speed is set to 500 rpm, and the process proceeds to step S19.

  In step S18, since the compressor load is small and the required quietness is the lowest vehicle state, the carrier frequency is set to 10 kHz, the edge steepness is set to a small time constant, and the motor rotational speed is set to 500 rpm, and the process proceeds to step S19.

  In step S19, it is determined whether or not the operation mode has been changed from the minute load operation to another load operation. If YES, this control is terminated, and if NO, the process proceeds to step S11.

(Small load operation)
FIG. 6 is used during the small load operation. Note that steps performing the same processing as in FIG.
In step S20, since the compressor load is relatively small and the required quietness is high, the carrier frequency is set to 15 kHz, the edge steepness is set to a large time constant, the motor rotational speed is set to 600 to 2,000 rpm, and the process proceeds to step S19. Transition.

  In step S21, since the compressor load is relatively small and the required quietness is not high, the carrier frequency is 10 kHz, the edge steepness is the time constant, the motor rotation speed is 600 to 2,000 rpm, step S19 Migrate to

  In step S22, since the compressor load is relatively small and the required quietness is low, the carrier frequency is set to 10 kHz, the edge steepness is set to a small time constant, the motor rotational speed is set to 600 to 2,000 rpm, and the process proceeds to step S19. Transition.

  In step S23, since the compressor load is relatively small and the required quietness is the lowest vehicle state, the carrier frequency is 7 kHz, the edge steepness is small, the motor speed is 600 to 2,000 rpm, step S19 Migrate to

(Medium load operation)
FIG. 7 is used during medium load operation. Note that steps performing the same processing as in FIG.
In step S24, since the compressor load is relatively high and the required quietness is high, the carrier frequency is 10 kHz, the edge steepness is the time constant, the motor rotation speed is 2,000 to 4,000 rpm, and the process proceeds to step S19. Transition.

  In step S25, since the compressor load is relatively high and the required quietness is not high, the carrier frequency is 7 kHz, the edge steepness is the time constant, the motor rotation speed is 2,000 to 4,000 rpm, step S19 Migrate to

  In step S26, since the compressor load is relatively high and the required quietness is low, the carrier frequency is 7 kHz, the edge steepness is small, the motor rotation speed is 2,000 to 4,000 rpm, and the process proceeds to step S19. Transition.

  In step S27, since the compressor load is relatively high and the required quietness is the lowest vehicle state, the carrier frequency is 7 kHz, the edge steepness is small, the motor speed is 2,000 to 4,000 rpm, step S19 Migrate to

(High load operation)
FIG. 8 is used during high load operation. Note that steps performing the same processing as in FIG.
In step S28, since the compressor load is high and the required quietness is high, the carrier frequency is 15 kHz, the edge steepness is the time constant, the motor rotation speed is 4,000 to 6,000 rpm, and the process proceeds to step S19. .

  In step S29, since the compressor load is high and the required quietness is not high, the carrier frequency is set to 10 kHz, the edge steepness is set to a small time constant, the motor speed is set to 4,000 to 6,000 rpm, and the process proceeds to step S19. To do.

  In step S30, since the compressor load is high and the required quietness is low, the carrier frequency is set to 10 kHz, the edge steepness is set to a small time constant, the motor rotational speed is set to 4,000 to 6,000 rpm, and the process proceeds to step S19. .

  In step S31, since the compressor load is high and the required quietness is the lowest vehicle state, the carrier frequency is 10 kHz, the edge steepness is small, the motor speed is 4,000 to 6,000 rpm, and the process proceeds to step S19 To do.

The operation will be described.
[Carrier frequency setting action according to vehicle condition]
(Engine RPM)
In Example 1, the required quietness score is increased and the carrier frequency is lowered as the engine speed is higher.
In a so-called hybrid vehicle having both an engine (internal combustion engine) and an electric motor, the engine may be stopped while traveling or stopped, and the most quiet is required in this state. On the other hand, in Example 1, quietness can be established at low cost by controlling at a high carrier frequency other than the audible band when the engine is stopped (engine speed 0 to 1,000 rpm).

  In addition, the engine speed and the noise level generated by the engine are proportional to each other. When the engine speed is high, the high noise level masks minute noise generated by the electric compressor A, but the engine speed is low. In some cases, this masking effect cannot be expected. Thus, in the first embodiment, when the engine speed is low, quietness can be established at low cost by controlling with a high carrier frequency other than the audible band.

(Vehicle speed)
In Example 1, the required quietness score is increased and the carrier frequency is lowered as the vehicle speed is higher.
Generally, the lower the carrier frequency, the smaller the switching loss of the IGBT. However, when the carrier frequency is lowered to the audible band, the quietness is deteriorated by the sound emitted from the motor winding. On the other hand, in Example 1, the required quietness can be established at low cost by selecting a higher carrier frequency as the vehicle speed is lower and the required quietness is higher.

[Pulse edge steepness setting action according to vehicle condition]
(Engine RPM)
In the first embodiment, the higher the engine speed, the greater the required quietness score and the higher the edge steepness (smaller the filter time constant).
In a so-called hybrid vehicle having both an engine and an electric motor, the engine may be stopped while traveling or stopped, and the most quiet is required in that state. On the other hand, in the first embodiment, when the engine is stopped, the edge steepness of the pulse is lowered, thereby reducing the harmonic component of the current flowing in the stator coil of the motor 5 and achieving quietness at low cost. .

  In addition, the engine speed and the noise level generated by the engine are proportional to each other. When the engine speed is high, the high noise level masks minute noise generated by the electric compressor A, but the engine speed is low. In some cases, this masking effect cannot be expected. Therefore, in the first embodiment, when the engine speed is low, by reducing the steepness of the edge of the pulse, the harmonic component of the current flowing in the stator coil of the motor 5 is reduced, and quietness is established at low cost. Can be made.

(Vehicle speed)
In the first embodiment, the required quietness score is increased and the edge steepness is increased (the filter time constant is decreased) as the vehicle speed increases.
In general, when a current containing a large amount of harmonic components (for example, a rectangular wave) is applied to a coil using windings, the core and the windings vibrate, and so-called “beat noise” is likely to occur. On the other hand, in Example 1, the lower the vehicle speed and the higher the required quietness, the lower the edge steepness, thereby reducing the harmonic component of the current flowing in the coil of the motor 5, and the required quietness. Can be established at low cost.

[Carrier frequency maintenance at high load]
In the first embodiment, the carrier frequency is lower as the required quietness score is larger during a minute load operation, a small load operation, and a medium load operation where the motor rotation speed is low. Sometimes, only the edge steepness is increased without changing the carrier frequency.

  That is, when the load is high, the motor drive current frequency and the carrier frequency are closer to each other than when the load is low. Therefore, the time resolution of the motor drive current waveform is increased, and controllability is degraded. On the other hand, in the first embodiment, it is possible to achieve both efficiency (cooling) and controllability by reducing only the edge steepness without lowering the carrier frequency.

Next, the effect will be described.
The control device for the electric compressor according to the first embodiment has the following effects.

  (1) A required quietness determination unit 7a for determining a required quietness score according to a vehicle state is provided, and the electric compressor control circuit 7 calculates a PWM carrier frequency and a pulse edge steepness based on the required quietness score. Control. Thereby, both silence and efficiency required according to the vehicle state can be achieved.

  (2) The electric compressor control circuit 7 increases the carrier frequency when the required quietness score is low than when the required quietness score is high. In other words, when the required quietness is high, the carrier frequency is increased, and the noise emitted from the motor winding is reduced to increase the quietness. When the required quietness is low, the carrier frequency is decreased. Increase efficiency by reducing IGBT switching losses. As a result, both silence and efficiency can be achieved.

  (3) The electric compressor control circuit 7 makes the edge steepness lower when the required quietness score is low than when the required quietness score is high. That is, when the required quietness is high, the edge steepness is lowered, and by reducing the harmonic components, the quietness is increased, and when the required quietness is low, the edge steepness is increased, and the start-up is started. Increase efficiency by reducing phase power loss. As a result, both silence and efficiency can be achieved.

  (4) When the vehicle speed is low, the required quietness determination unit 7a is required for the required quietness score to be smaller than when the vehicle speed is high, so that the required quietness changes according to the vehicle speed. Both quietness and efficiency can be achieved.

  (5) When the engine speed is low, the required quietness determination unit 7a makes the required quietness score smaller than when the engine speed is high, so that the required quietness changes according to the engine speed. On the other hand, it is possible to achieve both required silence and efficiency.

  (6) When the engine is stopped, the required quietness determination unit 7a makes the required quietness score smaller than when the engine is running. The required silence can be realized.

  (7) The electric compressor control circuit 7 suppresses an increase in the time resolution of the motor drive current waveform in order to increase the carrier frequency regardless of changes in the vehicle speed and the engine speed when the electric compressor A is under high load. Deterioration of controllability can be prevented.

The second embodiment takes into consideration the case where the passenger is listening to the radio.
Since the overall configuration is the same as that of the first embodiment, illustration and description are omitted.

[Pulse change control processing]
12 and 13 are flowcharts showing the flow of the pulse change control process of the PWM control executed by the electric compressor control circuit 7 of the second embodiment. Each step will be described below. Note that steps performing the same processing as in FIG.

(Micro load operation)
In step S31, it is determined whether the passenger is listening to the radio. If YES, the process proceeds to step S32. If NO, the process proceeds to step S12.

  In step S32, it is determined whether or not the required quietness score is 2 or less. If YES, the process moves to step S35, and if NO, the process moves to step S33.

  In step S33, it is determined whether or not the required quietness score is 3 or 4. If YES, the process proceeds to step S36, and if NO, the process proceeds to step S34.

  In step S34, it is determined whether or not the required quietness score is 5 or 6. If YES, the process proceeds to step S37, and if NO, the process proceeds to step S38.

  In step S35, since the compressor load is small and the vehicle is listening to the radio, the carrier frequency is set to 20 kHz, the edge steepness is set to a large time constant, and the motor rotational speed is set to 500 rpm, and the process proceeds to step S19. In the second embodiment, the carrier frequency and the edge steepness are set based on the maps shown in FIGS. In step S35, since the load level is 1 or less than the required quietness score 2, the carrier frequency is 20 kHz from FIG. 14, and the edge steepness is a large time constant from FIG.

  In step S36, since the vehicle is listening to the radio, the carrier frequency is set to 10 kHz, the edge steepness is set to a time constant, the motor rotation speed is set to 500 rpm, and the process proceeds to step S19.

  In step S37, since the vehicle is listening to the radio, the carrier frequency is set to 7 kHz, the edge steepness is set to a large time constant, the motor rotational speed is set to 500 rpm, and the process proceeds to step S19.

  In step S38, since the vehicle is listening to the radio, the carrier frequency is set to 7 kHz, the edge steepness is set to a large time constant, the motor rotational speed is set to 500 rpm, and the process proceeds to step S19.

  In the small load operation, the medium load operation, and the high load operation, the carrier frequency and the edge steepness are set from the load level and the required quietness score based on FIGS. That is, only steps S15 to S18 in FIG. 12 and steps S35 to S38 in FIG.

Next, the operation will be described.
The types of noise generated by the electric compressor A are roughly classified into radiation noise directly radiated from the motor 5 and so-called unnecessary radiation noise (noise radio wave) that generates unnecessary noise in the electric and magnetic fields by switching between high voltage and current. The

  Of these, radiation noise that causes noise in the vehicle interior electronic equipment such as radio refers to noise radio waves of 500 kHz to 100 MHz from the frequency band of broadcasting, but the carrier frequency used for driving the motor as in Example 1 is about 40 kHz at most. Yes, there is almost no effect because both frequencies have an opening of more than 10 times. However, when the edge steepness of the pulse is high, it has a harmonic component several hundred times as high as the carrier frequency, and therefore overlaps with the frequency band of broadcasting.

The reason why the carrier frequency is set to about 40 kHz is that the inductance of the motor winding is determined by the mechanical output of the motor 5, so there is no merit to the motor efficiency by increasing the carrier frequency, and the machine output This is because even a small motor (small inductance) has an upper limit of about 40 kHz.
Therefore, when the occupant is listening to the radio, the noise demodulated from the radio tuner as noise radio waves is larger than the radiated sound from the motor 5.

  On the other hand, in the first embodiment, when listening to the radio, the edge steepness is lowered to avoid the overlap between the frequency band of the broadcast and the frequency band of the edge of the pulse. Radio noise affecting silence can be reduced with priority, and silence can be improved.

  Note that the edge steepness can also cause a “growing sound” of the motor, so the edge steepness has been lowered within the range of control establishment (efficiency / heat resistance of the element) even when there is no radio listening. The setting with the lowest edge steepness (large time constant) is performed.

  Here, when the possible frequency of the carrier frequency (7 to 20 kHz in the second embodiment) is selected as 7 kHz which is the lowest frequency when there is no radio listening (required quietness score “4” for the load level “3” in FIG. 15). ”,“ 6 ”and“ 8 ”), when switching to radio listening, the carrier frequency cannot be lowered any more, and therefore the edge steepness cannot be lowered. The reason is that the power loss increases by lowering the edge steepness, so it is necessary to suppress the decrease in efficiency by lowering the carrier frequency.

  However, when there is no radio listening and the load level is high and the required quietness score is large (silence is not required) (load level “2” in FIG. 15—required quietness score “8”, load level “3”). “-Required quietness score“ 6 ”, load level“ 4 ”—required quietness score“ 4 ”portion) has a high edge steepness from the viewpoint of efficiency (energy saving), so when listening to the radio Priority is given to reducing radio noise over efficiency, and the edge steepness is lowered.

Next, the effect will be described.
In addition to the effects (1) to (7) of the first embodiment, the control device for the electric compressor of the second embodiment has the effects listed below.

  (8) When the occupant is listening to the radio, the electric compressor control circuit 7 has a lower edge steepness than when the occupant is not listening to the radio. The applied noise can be reduced with priority, and quietness can be improved.

  (9) The electric compressor control circuit 7 reduces the carrier frequency when the occupant is listening to the radio compared to when the occupant is not listening to the radio, thereby suppressing the decrease in efficiency due to the low edge steepness it can.

(Other examples)
As described above, the best mode for carrying out the present invention has been described based on each embodiment. However, the specific configuration of the present invention is not limited to the configuration of each embodiment, and each claim of the claims. Design changes and additions are allowed without departing from the spirit of the invention.

  For example, the number of required quietness scores according to the engine speed and the number of required quietness scores according to the vehicle speed are not limited to the four shown in the embodiment, and can be arbitrarily set. The same applies to the carrier frequency and the edge steepness of the pulse.

  In the embodiment, the example in which the edge steepness of the pulse is changed by switching three low-pass filters having different time constants is shown, but the method of changing the edge steepness is arbitrary.

It is a block diagram of the air conditioner of the hybrid vehicle (HEV) to which the control apparatus of the electric compressor of Example 1 is applied. FIG. 3 is a circuit configuration diagram of an inverter 6 according to the first embodiment. It is a figure which shows a pulse waveform when changing a time constant. It is a flowchart for the flow of the electric compressor load level determination control process executed by the electric compressor control circuit of the first embodiment. 4 is a flowchart showing a flow of a pulse change control process of PWM control during a minute load operation executed by the electric compressor control circuit 7 according to the first embodiment. 3 is a flowchart illustrating a flow of a pulse change control process of PWM control during a small load operation that is executed by the electric compressor control circuit 7 according to the first embodiment. 3 is a flowchart illustrating a flow of a pulse change control process of PWM control during a middle load operation that is executed by the electric compressor control circuit 7 according to the first embodiment. 3 is a flowchart illustrating a flow of a pulse change control process of PWM control during high load operation that is executed by the electric compressor control circuit 7 according to the first embodiment. 3 is a setting map for a required quietness score according to the first embodiment. 2 is a carrier frequency setting map according to the first embodiment. 3 is an edge steepness setting map according to the first embodiment. It is a flowchart which shows the flow of the pulse change control process of PWM control at the time of the micro load operation | movement performed with the electric compressor control circuit 7 of Example 2. FIG. 7 is a flowchart showing a flow of a pulse change control process of PWM control during a minute load operation executed by the electric compressor control circuit 7 of the second embodiment. 6 is a carrier frequency setting map according to the second embodiment. 6 is an edge steepness setting map according to the second embodiment.

Explanation of symbols

A Electric compressor 1 Compressor 2 Cooling condenser 3 Expansion valve 4 Evaporator 5 Three-phase AC synchronous motor 6 Inverter 7 Electric compressor control circuit 7a Required quietness determination unit 8 Air conditioner controller 8a Input device 8b Room temperature sensor 8c Air conditioner control circuit 11 Upper IGBT
12 Lower IGBT
13 Upper diode 14 Lower diode 15 IGBT driver 16 Edge steepness switch 16a Low-pass filter 16b Low-pass filter 16c Low-pass filter 16d Switch 17 Gate voltage amplification circuit

Claims (9)

An electric compressor mounted on the vehicle;
An inverter that drives the compressor;
Inverter control means for pulse width modulation control of the inverter;
In the control device of the electric compressor having
A required quietness determination means for determining a required quietness according to the vehicle state;
The inverter control unit controls at least one of the carrier frequency of the pulse width modulation and the edge steepness of the pulse based on the required quietness. In the control apparatus of the electric compressor according to claim 1,
The inverter control means, when the required quietness is high, makes the carrier frequency higher than when the required quietness is low. The control apparatus for an electric compressor according to claim 1 or 2, wherein the inverter control means makes the edge steepness lower when the required quietness is high than when the required quietness is low. A control device for an electric compressor. In the control apparatus of the electric compressor according to any one of claims 1 to 3,
The required quietness determining means determines that the required quietness is higher when the vehicle speed is low than when the vehicle speed is high. In the control apparatus of the electric compressor according to any one of claims 1 to 4,
The required quietness determination means determines that the required quietness is higher when the engine speed is low than when the engine speed is high. In the control apparatus of the electric compressor according to any one of claims 1 to 5,
The required quietness determination means determines that the required quietness is higher when the engine is stopped than when the engine is running. The control device for an electric compressor according to any one of claims 1 to 6,
The said inverter control means makes the said carrier frequency high regardless of the said vehicle state at the time of the high load of the said electric compressor, The control apparatus of the electric compressor characterized by the above-mentioned. In the control apparatus of the electric compressor according to any one of claims 1 to 7,
The said inverter control means makes the said steepness level low when the passenger | crew is listening to the radio, when not listening to the radio, The control apparatus of the electric compressor characterized by the above-mentioned. In the control apparatus of the electric compressor according to claim 8,
The said inverter control means makes the said carrier frequency lower when the passenger | crew is listening to the radio than when not listening to the radio, The control apparatus of the electric compressor characterized by the above-mentioned.

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