KR20060043624A - Gas heat pump type air conditioner - Google Patents

Abstract

An object of the present invention is to provide an air conditioner having a power generation function with high power generation efficiency.

The compressor 13 driven by the gas engine 11, the first blower 16 which is an electric refiller, the coolant pump 21, etc. are provided outdoors, and the 2nd blower which is an indoor unit installed indoors A gas heat pump type air conditioner having (33, 34) and the like, and a PWM converter 50 for regulating regenerative control of the synchronous motor 52 driven by the gas engine 11 and the synchronous motor 52 to obtain DC power. ) And a converter 40 for rectifying and smoothing a two-phase or three-phase AC commercial power source to obtain direct current power, and transmitting the power obtained by the PWM converter 50 while detecting the direct current power obtained by the converter 40. And a PWM converter 70 which is a control means for supplying as a power supply for the refiller or the indoor unit.

Gas Engines, Compressors, Blowers, Converters, PWM Converters

Description

Gas Heat Pump Type Air Conditioning Unit {GAS HEAT PUMP TYPE AIR CONDITIONER}

1 is a configuration diagram of a gas heat pump type air conditioner.

2 is a system block diagram showing a configuration of an electric system.

3 is a basic vector diagram.

4 is a current vector control system diagram.

5 is a graph showing the limit value of the engine output.

6 is a timing chart at startup.

7 is a timing chart at stop.

<Explanation of symbols for the main parts of the drawings>

11: gas engine

13: compressor

16: first blower

21: coolant pump

33, 34: second blower

40: converter

41: commercial AC power

50: power generation PWM converter

52: synchronous motor

60: load inverter

70: PWM converter

[Document 1] Japanese Unexamined Patent Publication No. 2001-324240

The present invention relates to a gas heat pump type air conditioner that drives a compressor by a gas engine, and more particularly, to a gas heat pump type air conditioner that generates power by the gas engine.

Background Art Conventionally, in a gas heat pump that drives a compressor by a gas engine, a gas heat pump type air conditioner that drives an alternator to generate alternating electric power by the power of the gas engine has been known.

For example, Document 1 discloses a power generation apparatus having a generator that is driven by a gas engine driving a compressor and outputs an alternating current output. In addition, the generator includes an AC / DC converter that converts the AC power output from the generator into DC power, and a DC / AC converter that converts the DC power converted by the AC / DC converter into AC power of a specified frequency and supplies it to an electric device. Have

Here, the AC / DC conversion and DC / AC conversion are performed because the engine rotational speed changes with the variation of the load of the gas heat pump, and the output frequency and the output voltage which are generated change. For sake. The conversion to the prescribed value of the commercial power supply is for enabling the system linkage with the commercial power supply.

However, the conventional gas heat pump type air conditioner has the following problems.

(1) In the invention described in Document 1, it is necessary to provide a second converter with a synchronization function or a protection device that synchronizes the electrical system, voltage, frequency, etc. of the commercial power source in order to grid-connect the commercial power source. There was.

(2) In the invention described in Document 1, there is a problem that the output load of the gas engine increases at the start of the gas engine.

(3) In the invention described in Document 1, the DC voltage obtained by AC / DC conversion of generated power is controlled to be a prescribed set voltage. The DC voltage level is generally set to a voltage value at which the inflow from the AC commercial power source becomes zero. Since AC commercial power is 202 ± 20 V, the DC voltage set by the AC / DC converter must be set to a value higher than 222 × (√2) = 314 V. This condition is normally set to 320V.

However, on average, it is good to set the value higher than 202 x (√2) = 286 V, and 320 V is a voltage value at which the AC commercial power supply is zero in all cases. By the way, the difference of (320-286) V compared with the average value worsens the power generation efficiency.

This is because the copper loss of the motor = armature coil resistance x (armature current) ² , the iron loss of the motor = (organic voltage) ² / equivalent iron loss resistance, so that the iron loss of the motor rises when the voltage is high. In addition, losses in switching devices and other components also increase.

In this way, there is a problem that the loss increases on average by controlling the conventional DC voltage constantly.

Therefore, an object of the present invention is to solve such a problem and to provide an air conditioner having a power generation function having high power generation efficiency.

In order to solve the said subject, the gas heat pump type air conditioner of this invention has the following structures.

(1) A gas heat pump type air conditioner having a compressor driven by a gas engine, an outdoor unit installed outdoors with an electric refiller, and an indoor unit installed indoors, comprising: a synchronous motor driven by a gas engine; And a PWM converter for regeneratively controlling the synchronous motor to obtain direct current power, and supplying the electric power obtained from the PWM converter as a power supply for an electric replenisher or an indoor unit in the outdoor unit.

(2) The gas heat pump type air conditioner described in (1), further comprising a converter for rectifying single-phase or three-phase AC commercial power, and the consumption of the electric replenisher or the indoor unit in the outdoor unit. When the electric power obtained by the said PWM converter is insufficient with respect to electric power, when the electric power obtained by the said PWM converter exceeds the power consumption, while supplementing an unknown power from a commercial power supply through the said converter, the said DC power It is characterized by controlling the DC voltage of to the lowest voltage at which the inflow current from commercial power becomes zero.

(3) The gas heat pump type air conditioner described in (1), wherein the PWM converter is controlled by a PWM inverter so that the synchronous motor is driven backward by electric power flowing from the single-phase or three-phase AC commercial power supply side. It is characterized by having a driving control means.

Next, an embodiment of the gas heat pump type air conditioner according to the present invention will be described below with reference to the drawings. 1 is a configuration diagram of a gas heat pump type air conditioner according to the present embodiment.

The gas heat pump type air conditioner includes an outdoor unit 10, an indoor unit 30, and a refrigerant circulation passage 1 circulating the outdoor unit 10 and the indoor unit 30.

The outdoor unit 10 includes a gas engine 11 for driving the compressors 13A and 13B, an accumulator 12 which completely separates the gaseous refrigerant and the liquid refrigerant, and an outdoor heat exchanger that performs heat exchange of the refrigerant for air conditioning. Has 14 The gas engine 11 is connected with a synchronous motor 52 which is a generator.

The indoor unit 30 has an indoor heat exchanger 31 for performing heat exchange with indoor air and a refrigerant, and an expansion valve 32 for expanding the refrigerant.

The compressor 13 sucks gaseous refrigerant and discharges the high pressure gaseous refrigerant.

Next, the operation when cooling the room will be described. The gas engine 11 is driven by the fuel gas to drive the compressors 13A and 13B. The compressors 13A and 13B suck and compress the gaseous refrigerant of the accumulator 12 and discharge it as gas in a high temperature and high pressure state. In the discharged gaseous refrigerant, the oil separator 19 separates oil from the refrigerant. The refrigerant from which the oil is separated is introduced into the outdoor heat exchanger 14 by the four-way valve 17.

The high temperature and high pressure gaseous refrigerant is cooled in the outdoor heat exchanger 14 to liquefy. The liquefied refrigerant is expanded by the expansion valve 32 via the filter drier 22, the ball valve 23, and the strainer 31n, and becomes low temperature.

The coolant which has become low temperature reaches the indoor heat exchanger 31 via the strainer 31m, and cools the indoor air. The refrigerant is then returned to the accumulator 12 via the double tube heat exchanger 18. The coolant is stored in the accumulator 12 in a state in which it is separated into a liquid refrigerant and a gaseous refrigerant.

Next, the action at the time of heating an interior is demonstrated. The gas engine 11 is driven by the fuel gas to drive the compressors 13A and 13B. The compressors 13A and 13B suck and compress the gaseous refrigerant of the accumulator 12 and discharge it as gas in a high temperature and high pressure state. The discharged gaseous refrigerant is separated from the refrigerant in the oil separator 19. The refrigerant from which the oil is separated is introduced into the indoor heat exchanger 31 by the four-way valve 17. The high temperature and high pressure refrigerant heats indoor air in the indoor heat exchanger (17).

The refrigerant is then expanded in the expansion valve 32 via the strainer 31 and reaches the outdoor heat exchanger 14 via the ball valve 23 and the filter drier 22. The accumulator 12 is then returned to the accumulator 12 via the four-way valve 17 and the double heat exchanger 18.

The synchronous motor 52 connected to the gas engine 11 generates electric power when the gas engine 11 has room.

In the gas heat pump type air conditioner according to the present embodiment, a cooling water pump 21 for cooling the first blower 16 and the gas engine 11 blown to the outdoor heat exchanger 14 is provided as a refiller in the outdoor unit. It is. Further, as the indoor unit, second blowers 33 and 34 for blowing air to the indoor heat exchanger 31 are provided.

In addition to the replenisher, there are other motors, solenoid valves, control boards for outdoor units, control boards for indoor units, and motors for changing the wind direction plate of the indoor unit 30.

Next, the configuration of the electric system is shown in FIG. 2 as a system block diagram.

The gas engine 11 is connected with a synchronous motor 52 which is a generator. From the synchronous motor 52, three AC wires 53 emerge and are connected to the power generation PWM converter 50. Two of three of the AC wires 53 are provided with a current transformer 51 for detecting a current value. Two DC wires 54 emerge from the power generation PWM converter 50.

On the other hand, the AC commercial power supply 41 is input to the converter 40. The converter consists of six diodes 42 and an electrolytic capacitor 44. The electric current sensor 43 is attached to the electric wire.

The DC wires 54 output from the power generation PWM converter 50 are connected to two DC wires output from the converter 40, respectively, and are connected to the load inverter 60. The load current sensor 55 is attached to the DC wire. A replenisher 90 such as a motor is connected to the load inverter 60.

The current transformer 51, the current sensor 43, the DC voltage detector 45, and the load current sensor 55 are connected to the PWM converter control means 70, which is a microcomputer for controlling the power generation PWM converter 50. have.

The motor controller 80 is connected to the load inverter 60.

3 shows a basic vector diagram as a dq diagram. The voltage equation is represented by [Equation 1].

Where νa, νb, υc are the armature voltages of the respective phases. ia, ib and ic are the armature currents in each phase. νd and νq are d, q-axis components of the armature voltage. id and iq are d and q-axis components of an armature current. Ra is the armature coil resistance. Ld and Lq are d and q-axis inductances. p is the derivative operator (p = d / dt). ω is the armature angular velocity of the synchronous motor 52. ψ a is the armature linkage magnetic flux of the permanent magnet.

Next, control is shown in FIG. 4 as a current vector control system diagram. The DC voltage optimum control 64 is connected to the torque calculating section 63 and the vector current control algorithm 65. The torque calculator 63 is connected to the vector current algorithm 66 and the estimation algorithm 66.

The power generation PWM converter 50 operates by control of either DC voltage optimum control in the first operation mode or output limit control in the second operation mode. In the DC voltage optimum control, all the power required by the load inverter 60 is supplied from the synchronous motor 52. On the other hand, in the output limiting control, the required power is supplied in cooperation with the synchronous motor 52 and the commercial power supply 41.

First, DC voltage optimum control which is a 1st operation mode is demonstrated.

In the DC voltage optimum control 64, a commercial current inflow value IO (n), a DC voltage actual value Vdc (n), and a DC voltage command initial value Vdc (0) are input. In this case, the DC voltage needs to be DC 282 V or more in order to make the voltage applied to the load an effective value of AC 20 O V.

There are three ways to achieve that. The first method is a method of always monitoring so that the inflow current from a commercial power supply becomes zero.

In the second method, the DC voltage is increased to about 1 V / sec so that the inflow current from the commercial power supply becomes zero at the start of the power generation PWM converter 50, and the voltage is constantly controlled at that value, and thereafter, Similarly, if there is an inflow current, the voltage is increased to about 1 V / sec. In this case, however, it is required to be DC 282 V or more.

The third method is a method of detecting the DC voltage at the time of full load stop by stopping the power generation PWM converter 50 at the start and controlling the voltage at a voltage of 5 to 6 V added to this value. That is, the voltage from a commercial power supply is measured in the synchronous state of the synchronous motor 52, and 5-6V is added to the value.

The third method is the most suitable method because it does not require an extra sensor.

The DC voltage command value [Vdc *] is output from the DC voltage optimum control 64 by any of the above methods.

Next, the torque calculating part 63 is demonstrated. The DC voltage command value [Vdc *] is input from the DC voltage optimum control 64 to the torque calculation part 63, and the DC current actual value [Idc (n)] of the load side is input. In addition, the rotor angular velocity [omega m (n)] of the synchronous motor 52 is input from the estimation algorithm 66. From these values, the extraction output P (M) from the synchronous motor 52 is calculated using [Equation 2].

Idc (n) is a direct current measurement value at the load side, and (n) indicates a sample value at the time of processing.

As described later, the output P (M) of the synchronous motor 52 may always be limited in output when the load of the air conditioning compressor is large in summer. In other words, when the extraction power from the generator is not limited, the extraction power from the synchronous motor = the total required power of the load side motor is obtained. On the other hand, when the extraction power from the generator is limited, the extraction power from the synchronous motor + the power from the commercial power supply = the total required power of the load side motor becomes ".

Next, using Equation 3, the equation expressing iq as a function of id is obtained and output as Iq *.

Where T * is the torque. Pn is maximal. ψa is an induced voltage and is a constant. (Ld-Lq) is a fixed value.

The output current from the synchronous motor 52 always imposes a limit on the limit current Ia of the synchronous motor 52 as shown in [Equation 4].

Here, Ie is a phase current effective value. a and b are coefficients determined from the motor characteristics of the synchronous motor 52. That is, in order to prevent the synchronous motor 52 from being excessively heated, the output current from the synchronous motor 52 is limited.

Equation (4) means that when the square root √ (id ² + iq ² ) of the square sum of id and iq obtained is greater than √3 (a · ω + b), it is determined as √3 (a · ω + b) Id and iq are determined based on Ia.

That is, if id and iq calculated on the basis of the required power on the load side exceed the limit of the synchronous motor 52 which is the generator, the condition that satisfies [Equation 5], [Equation 2] and [Equation 3] is satisfied. It is determined that this does not exist and the output becomes the same as the limited state.

However, it can obtain | require from the simultaneous equation of [Equation 5] and [Equation 4].

Since the generator alone cannot supply the total load-side power, Vdc in Equation 5 becomes Vdc * = Vdc (n), like the output limit control, in order to lower the DC voltage and take power from the commercial power supply.

Next, the vector current control algorithm 65 will be described. The DC current command value Vdc * is input to the vector current control algorithm 65 from the DC voltage optimum control 64. In addition, Iq * is input from the torque calculation part 63. FIG. In addition, the rotor angular velocity [omega m (n)] of the synchronous motor 52 is input from the estimation algorithm 66.

The vector current control algorithm 65 obtains id based on [Equation 5].

Here, Vdc * is a DC voltage command value and Vdc (IO = 0). In addition, Vdc (0) is a current voltage command initial value, and is 282V in this embodiment. In addition, IO (n) is a commercial power supply current measured value, and (n) is a sample value at the time of processing.

Vdc * is set to 282V as an initial value, and PI control so that IO (n) = 0 in the form which adds the deviation from the target value of IO (n). However, it is assumed that Vdc * = 282 to 320V.

Next, the specific procedure of DC voltage optimum control is demonstrated.

(a) Set Vdc (0) = 282 V (initial value).

(b) Measure IO (n) at 1 second intervals.

(c) If IO (n) is greater than zero, Vdc is increased by 1V.

(d) Repeat (b) and (c) and set Vdc when the IO (n) becomes 0 as the DC voltage command value (Vdc *). Vdc * = Vdc [IO (n) = O]

(e) The electric power [P (M) *] extracted from [Equation 2] is calculated from Vdc * thus obtained and the DC voltage actual value [Idc (n)] required by the load side.

(f) The torque T * is calculated from the angular speed ω and P (M) * of the synchronous motor 52.

T * = P (M) * / ω

(g) Substituting Vdc *, ω, and other constants obtained in this manner into [Equation 5] and [Equation 3] yields a system of equations of id and iq to obtain id and iq from them.

Here, in (e), Vdc * .Idc (n) is compared with P (M) Lim. When the comparison result is Vdc * IdC (n)> P (M) Lim, the motor output is limited. In this case, Vdc * is an actual value (voltage value actually required by the load side).

In addition, when id and iq obtained in (g) become √ (id ² + iq ² )> √3 (a · ω + b), current is limited because a current above the limit current of the motor flows. In this case, id and iq are found from the system of equations between Equation 5 and √ (id ² + iq ² ) = √3 (a · ω + b).

The id and iq obtained in this way are output as optimum current command values id * and iq *. Next, in the PI control, id * and iq * are substituted into [Equation 1] to obtain υd and υq, and input them into the two-phase / 3-phase and rotation / stop transformation 62.

In the two-phase / 3-phase and rotation / stop conversion 62, υd and υq are converted into νa, υb, υc and input to the PWM converter 52 as three-phase currents ia, ib, and ic. That is, νa, νb, and νc are three-phase modulated waves, and function as a gate signal for switching control of an IGBT (insulated gate bipolar transistor: semiconductor switching element) in a PWM converter by comparison with a triangular carrier wave.

In id * and iq *, id (n) and iq (n) which measured ia and ic by the measuring device 51, and were converted by the three phase / 2 phase stop / rotation conversion 67 are fed in, and input is carried out. It controls so that the deviation of the output id (n) and iq (n) may become 0 with respect to id * and iq *.

The output limit control which is a 2nd operation mode is demonstrated. In the output limiting control, it is operated in such a manner that the electric power required by the power generation output of the synchronous motor 52 is compensated for from the commercial power supply.

5 shows a graph of the engine power limit value. The horizontal axis represents the external limit command value Vs, and the vertical axis represents the percentage of the engine output P (E / G). Vs is a command value given from the main controller of GHP to PWM converter control means 70 which is a controller for generators. The setpoint is given at an interval of 10 seconds or more as an analog input of 0 to 5V. P (E / G) is a ratio given to the generator, not the ratio of the total engine power. At 20 hp GHP, the engine output is about 15 kW, but the generator is given up to 2 kW. In other words, P (E / G) = 100% is 2 kW.

When the demand for air conditioning in summer is high and the load on the compressor is large, power generation is stopped to give priority to air conditioning.

The output P (M) of the synchronous motor 52 is P (E / G) η (M). Here, η (M) is the motor efficiency.

The output limit value P (M) Lim of the synchronous motor 52 is limited to the smaller of the limit by P (E / G) and [Vdc * .Idc (n)].

Next, the vector control algorithm 65 will be described.

In the case of Vdc * · Idc (n)> P (M) Lim, Vdc * = Vdc (n) in Equation (5). Equation 2 is represented by Equation 3 as P (M) * = P (M) Lim. Here, Vdc (n) is a measured value of direct current. (n) is a sample value at the time of processing. As a result, the rising or falling speed of the P (M) value is limited in consideration of the engine torque fluctuation.

On the other hand, in the case of Vdc * · Idc (n) < P (M) Lim, Vdc * = Vdc (IO = 0) in Equation (5). In formula (2) or (3), P (M) * = Vdc * · Idc (n).

The shortage of the synchronous motor 52 which is a generator is supplemented by the power generation PWM converter 50, and electric power is supplied to a load via the electrolytic capacitor 44 of direct current | flow (part where the initial value was 282V). The electric wire to which the electrolytic capacitor 44 is attached becomes a DC intermediate bus.

When the motor output is limited, the load current is insufficient only by the current (charge) supplied from the power generation PWM converter 50 to the electrolytic capacitor 44, and the voltage of the electrolytic capacitor 44 is lowered. When the voltage of the electrolytic capacitor 44 decreases, the voltage is determined at the point where the current flows from the commercial power supply and the balance is maintained. Use this as Vdc.

However, even if the motor output is limited, if the motor output is lowered at once, the voltage balance may also be hunted along with the load fluctuation to the engine. Therefore, in consideration of engine torque, limit the rise or fall speed of the P (M) value. have. In practice, it is slowing down generator power quite slowly.

The time chart of the gas heat pump type air conditioner having the above configuration will be described. First, control at start-up will be described.

6 shows a timing chart at startup. If there is a GHP operation command, the commercial power supply is input to drive the cooling pump Wp. Next, the gas valve is opened to start the engine 11. Here, the PWM converter control means 70 which drives back the synchronous motor 52 with the electric current which flows in from the AC commercial power supply 41 by controlling the power generation PWM converter 50 with a PWM inverter is provided. In order to use the synchronous motor 52 as a starting device, high torque control is performed, and the power generation PWM converter 50 can be operated as a PWM inverter by performing gate control in a predetermined pattern from the PWM converter control means 70.

That is, by using the engine starter motor as the synchronous motor 52, the starter motor and the starter motor power supply unit can be reduced.

After 35 to 160 seconds have elapsed after starting the engine, the compressor 13 and the first blower 16 are driven. Thereafter, the four-way valve is controlled within 60 seconds. Operation of the power generation converter PWM 50 is commanded after 5 seconds of compressor switching or 10 seconds of four-way valve switching.

At the same time as the generator output comes out, the input of the commercial power supply is lowered, which is basically zero.

That is, the power generation PWM converter 50 operates by controlling any one of the DC voltage optimum control in the first operation mode or the output limit control in the second operation mode as described above. In the DC voltage optimum control, all the power required by the load inverter 60 is supplied from the synchronous motor 52. On the other hand, in the output limiting control, the required power is supplied in cooperation with the synchronous motor 52 and the commercial power supply 41.

Next, normal stop control will be described.

7 shows a timing chart at stop. If there is a GHP stop command, the operation stop of the power generation PWM converter 50 is immediately commanded. At the same time the generator is stopped, the commercial power is increased to supply power to cooling pumps and compressors.

Next, the compressor is stopped and the gas valve is closed. As a result, the engine stops. After closing the gas valve, the fan is stopped for up to 180 seconds. After that 10 seconds, the cooling water pump is stopped.

As described above, according to the gas heat pump type air conditioner of the present embodiment, the compressor 13 driven by the gas engine 11, the first blower 16 which is an electric refiller, and the coolant pump 21 are used. And a gas heat pump type air conditioner having an outdoor unit installed outdoors and second blowers 33 and 34 which are indoor units installed indoors, and the like, and a synchronous motor 52 driven by the gas engine 11. ), A PWM converter 50 for regeneratively controlling the synchronous motor 52 to obtain DC power, a converter 40 for rectifying and smoothing two-phase or three-phase AC commercial power and obtaining DC power, and a converter ( Since it has a PWM converter control means 70 which is a control means for supplying the electric power obtained in the PWM converter 50 as an electric refiller in the outdoor unit or the power of the indoor unit while detecting the DC power obtained in 40), it operates with an AC commercial power source. Being The risk of electrical influence on external electrical equipment is reduced. In addition, cost reduction can be realized by eliminating the synchronization function or protection device that synchronizes the voltage or frequency for system linkage.

Further, the gas heat pump type air conditioner of the present embodiment has a current sensor 43 which is a current detecting means for detecting a current flowing from the AC commercial power supply 41, and the inflow current when the current detecting means detects the inflow current. Since the PWM converter has a DC voltage control means for controlling the DC voltage of the generated DC power, it is possible to obtain the minimum voltage necessary for driving the electric replenisher or the indoor unit in the outdoor unit of the gas heat pump. In particular, the iron loss of the motor can be reduced, and the loss in the switching device and other components can also be reduced.

In this way, by controlling the conventional direct current voltage constantly, the loss that has increased on average can be reduced.

In addition, the gas heat pump type air conditioner of the present embodiment has a PWM converter control means 70, which is a reverse driving control means for driving the synchronous motor with the current flowing from AC commercial power by controlling the PWM converter with a PWM inverter. Therefore, the starter motor for starting the engine can be used as the synchronous motor 52, so that the power supply unit for the starter motor can be reduced. In particular, the synchronous motor 52 has a high starting torque and is suitable for a starting device requiring a low speed and high output torque. Conventionally, there have been cases where an induction motor is used as a starting device, but when the induction motor has a low starting torque and needs to be used as a starting device, a large starting current is required from a commercial power supply and the inverter needs to be enlarged to increase the size. According to the problem can be solved.

As mentioned above, although one Embodiment of the gas heat pump type air conditioner which concerns on this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.

For example, although the compressor and the blower are driven as a refiller in the Example, you may drive the solenoid valve etc. which are other refillers.

The gas heat pump type air conditioner of the present invention has the following effects and effects.

The gas engine driving the compressor has an extra capability for the necessary air conditioning capability and generates electricity by the extra capability of the gas engine.

The gas engine rotationally drives the rotating shaft of the synchronous motor for power generation. The PWM converter regeneratively controls the synchronous motor to obtain DC power. The power generation action is performed by supplying this DC power as a power supply for an electric refiller or an indoor unit of an outdoor unit. The present invention can realize higher efficiency power generation by controlling by using a PWM converter capable of controlling the high efficiency synchronous motor having a permanent magnet embedded therein most appropriately.

In addition, since the AC power obtained from the PWM converter is supplied as an electric replenisher in the outdoor unit of the gas heat pump or an indoor unit without supplying the system to the AC commercial power source, it is possible to reduce the electric influence on the external electric device operated by the AC commercial power source. In addition to reducing concerns, cost savings can be achieved by eliminating synchronous functions and protection devices that synchronize voltages and frequencies for system linkage. In this case, the DC power obtained by the PWM converter can be converted into AC power by a load inverter or the like and supplied to an electric supplement.

In addition, when the current detecting means detects the inflow current from the AC commercial power supply, the DC voltage of the DC power generated by the PWM converter is controlled to reduce the inflow current to zero, so that electric replacement in the outdoor unit of the gas heat pump is performed. The minimum voltage required to drive the air conditioner or indoor unit can be obtained, thereby reducing the iron loss in particular of the motor and also reducing the loss in switching devices and other components. Therefore, the loss as described above can be reduced as compared with the conventional DC voltage constant control.

In addition, since the PWM converter is controlled by the PWM inverter, it has a reverse driving control means for driving the synchronous motor with the current flowing from the AC commercial power, so that the output load of the gas engine can be reduced at the start of the gas engine. Here, the synchronous motor is suitable for the starter motor that requires a high output torque at a low speed due to high starting torque, so that the starting stability of the gas engine can be improved.

Claims (3)

In a gas heat pump type air conditioner having a compressor driven by a gas engine, an outdoor unit installed outdoors with an electric refiller, and an indoor unit installed indoors, A synchronous motor driven by the gas engine, A PWM converter for regeneratively controlling the synchronous motor to obtain direct current power, The gas heat pump type air conditioner which supplies the electric power obtained by the said PWM converter as the electric refiller in the outdoor unit, or the electric power of the indoor unit. According to claim 1, further comprising a converter for rectifying single-phase or three-phase AC commercial power, When the power obtained by the PWM converter is insufficient for the power consumption of the electric replenisher or the indoor unit in the outdoor unit, the power obtained from the PWM converter exceeds the power consumption while supplementing the unknown power from the commercial power supply through the converter. The gas heat pump type air conditioner, wherein the direct current voltage of the direct current power is controlled to the lowest voltage at which the inflow current from the commercial power supply becomes zero. 3. The gas heat pump type according to claim 2, further comprising a back driving control means for driving the synchronous motor back with electric power flowing from the single-phase or three-phase AC commercial power supply by controlling the PWM converter with a PWM inverter. Air conditioner.

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