KR20130105239A - Motor drive device, fluid compression system and air conditioner - Google Patents

Abstract

PURPOSE: A motor drive device, a fluid compression system, and an air conditioner prevent the demagnetization of a permanent magnet by changing an over-current protection stop threshold value to less than a demagnetization current value. CONSTITUTION: An inverter circuit (11) converts a DC voltage to an AC voltage. A current detector (20) detects DC supplied to the inverter circuit. A control device controls the on and off of a switching device. The processing of a device short-circuit protection device (12) is performed without starting a microcomputer. The processing of the control device is performed by starting the microcomputer. [Reference numerals] (10) Power module; (100) Motor driving device; (11) Inverter circuit; (12) Device short-circuit protection device; (13) Inverter driving circuit; (20) Current detector; (30) Amplifier; (300) Converter circuit; (40) Inverter control device; (41) Motor current reproduction unit; (42) Speed instruction unit; (43) Overcurrent determination unit; (44) Driving signal generation unit; (AA) PWM signal

Description

TECHNICAL FIELD [0001] The present invention relates to a motor drive device, a fluid compression system, and an air conditioner,

The present invention relates to a motor drive apparatus, a fluid compression system, and an air conditioner.

The air conditioner circulates indoor air to the heat exchanger by rotating the indoor fan installed in the indoor unit, exchanges heat with the refrigerant flowing through the heat exchanger to heat or cool the air, and blows air into the room by the indoor fan, . Further, a compressor constituting a part of the heat pump cycle is provided in the outdoor unit of the air conditioner, and the refrigerant is compressed by the compressor and discharged at a high temperature and a high pressure.

Ferrite magnets are used as permanent magnets provided in the motor of the compressor, and rare earth magnets such as neodymium magnets are used when performance is important. Incidentally, ferrite magnets are easily demagnetized in a low-temperature environment, and rare-earth magnets have a characteristic of being easy to potato at high temperatures. Here, " potato " means that the magnetic moment of the entire magnet is reduced by a temperature rise due to an overcurrent of the magnet, or a reverse magnetic field due to a current flowing into the coil.

In an environment in which the air conditioner is used, the temperature around the motor inside the compressor becomes very low at almost the same temperature as the outside temperature at the start of the heating operation in the winter, Because it operates in the open air, it becomes very hot.

Therefore, the compressor installed in the outdoor unit is inevitably driven in a low-temperature environment or a high-temperature environment, and furthermore, a high driving ability is required. If a high driving ability is to be exhibited in accordance with an operation demand based on room temperature, outdoor temperature, or the like, the current flowing to the motor increases. Thereby, there is a possibility that permanent magnets (ferrite magnets or rare earth magnets) provided in the motor are potentiated.

Further, in order to prevent destruction of the switching element provided in the inverter circuit in addition to the potato, it is necessary to suppress the current flowing through the switching element to a predetermined allowable current value or less.

As a conventional technique for partially addressing these problems, the following technique is known.

For example, in Patent Document 1, a motor phase current is calculated by a phase current calculation unit (current reproduction unit) based on the output of a DC current detection circuit (current detector), and when the motor phase current is higher than a predetermined threshold value , A brushless motor drive apparatus for a compressor including a current limiting function for lowering the frequency of a brushless motor when the motor is in a low-speed state.

In the technique described in Patent Document 1, the potential of the permanent magnet is prevented from being reduced by changing the overcurrent protection stop threshold value determined by the voltage comparison circuit to a predetermined value less than the potato current.

In Patent Document 2, the control circuit controls the IGBT (Insulated Gate Bipolar Transistor) on / off to drive the motor. When the current limiting command signal is input from the current limiting circuit, the IGBT is turned off, Is disclosed. The current limiting circuit outputs a current limiting command signal to the control circuit when the load current exceeds a predetermined upper limit value of the overcurrent. As a result, the permanent magnet provided in the motor is prevented from being demagnetized.

Japanese Patent Application Laid-Open No. 2009-198139 Japanese Patent Application Laid-Open No. 07-337072

However, when a short-circuit current flows in the inverter circuit due to a malfunction or the like, it is necessary to stop the inverter circuit at a moment (within several microseconds) in order to prevent breakdown of the switching element.

However, in the techniques described in Patent Documents 1 and 2, since the stop instruction to the inverter circuit is issued through the microcomputer, a delay of the cycle time (approximately 10 to several hundreds of microseconds) of the microcomputer occurs. Therefore, it is necessary to predict the cycle time and to set the operation threshold value of the overcurrent protection means to be lower than the original threshold value. In addition, although the problem can be avoided by using a microcomputer having a short cycle time, a microcomputer having a cycle time of several microseconds is expensive compared with that used in ordinary household appliances. Therefore, if such a microcomputer is mounted on an air conditioner, price competitiveness of the product is deteriorated.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a highly reliable motor drive apparatus, a fluid compression system, and an air conditioner

In order to solve the above problem, the present invention is characterized in that, when the current value inputted from the current detection means exceeds the short-circuit protection threshold value for preventing a short circuit in the inverter circuit, And the control means estimates the motor current flowing into the motor from the current value inputted from the current detecting means and judges whether the motor current is lower than the temperature protection of the switching element and / And the processing of the element short-circuit protection means is executed without interposing the microcomputer, and the processing of the control means is executed through the microcomputer .

According to the present invention, a highly reliable motor drive apparatus, a fluid compression system, and an air conditioner can be provided.

1 is a system configuration diagram including a motor drive apparatus according to a first embodiment of the present invention;
Fig. 2 (a) is a flow chart showing the flow of processing by the overcurrent judging unit, and Fig. 2 (b) is a flow chart showing the flow of processing by the short-
3 is an explanatory diagram schematically showing a temporal change of a motor current when a short-circuit current flows in an inverter circuit;
4 is a system configuration diagram including a motor drive apparatus according to a second embodiment of the present invention;
5 is a graph showing changes in absolute value of a motor winding temperature, a motor potato current, a motor potato protection threshold value, and a short-circuit protection threshold value in a motor using permanent magnets having low-temperature potato characteristics.
6 is a graph showing changes in absolute value of the motor winding temperature, motor potato current, motor potato protection threshold value, and short-circuit protection threshold value for a motor using a permanent magnet having a high-temperature potato characteristic.
7 is a system configuration diagram including a motor drive apparatus according to a third embodiment of the present invention;
8 is a graph showing changes in element absolute ratings, element short circuit protection threshold, temperature breakdown current value, device temperature protection threshold, and current limit threshold value of the switching element of the inverter circuit.
9 is a flow chart showing the flow of processing of the element temperature protection overcurrent determining section provided in the motor driving apparatus according to the third embodiment of the present invention.
10 is a system configuration diagram including a motor drive device according to a fourth embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings, the same reference numerals are given to common parts, and redundant explanations are omitted.

&Quot; First embodiment "

<System configuration>

1 is a system configuration diagram including a motor driving apparatus according to a first embodiment of the present invention.

The AC power supply 200 shows a power source of AC power transmitted from a power plant (not shown) or the like.

The converter circuit 300 is a circuit for converting an AC voltage input from the AC power source 200 into a DC voltage and includes a diode bridge in which diodes D1 and D3 are connected in series in a forward direction and their interconnection points are used as a converter input terminal . The same applies to the diodes D2 and D4. A smoothing capacitor C for smoothing pulsating components included in the DC voltage is connected in parallel with the diode bridge.

A "DC power supply" is constituted by the AC power supply 200 and the converter circuit 300 connected to the AC power supply 200. [

The motor driving apparatus 100 converts a DC voltage input from the converter circuit 300 into a predetermined AC voltage by inverter control and outputs the AC voltage to the motor M. [ Details of the processing performed by the motor driving apparatus 100 will be described later.

The motor M is, for example, a permanent magnet type synchronous motor and is connected to the inverter circuit 11 through a three-phase winding. That is, the motor M rotates by sucking a permanent magnet (not shown), which is a rotor, by a rotating magnetic field generated by an alternating current flowing into the three-phase winding. The motor M is used for a compressor (not shown) constituting a heat pump cycle of, for example, an air conditioner (not shown).

&Lt; Configuration of Motor Drive Apparatus >

As shown in FIG. 1, the motor drive device 100 includes a power module 10, a current detector 200, an amplifier 30, and an inverter control means 40.

The power module 10 includes an inverter circuit 11 including a plurality of switching elements (not shown) for outputting a predetermined AC voltage to the motor M and element short-circuit protection means 12 for protecting the switching elements And an inverter driving circuit 13 for driving the switching elements are integrated intensively.

The current detector 20 is connected in series to a bus line between the converter circuit 300 and the inverter circuit 11 to detect a direct current supplied to the inverter circuit 11 and output the detected current to the amplifier 30 ) And the device short-circuit protection means (12).

The amplifier 30 has, for example, a transistor, amplifies the detection signal input from the current detector 20, and outputs the amplified detection signal to the motor current reproducing unit 41 of the inverter controlling means 40.

The inverter control means (control means) 40 calculates an AC voltage to be applied to the motor M based on the detection signal input from the amplifier 30 and the rotation speed command value ω of the motor M And converts it into a driving signal and outputs it.

The rotation speed command value ω is determined based on set temperature information input from a remote controller (not shown) or a room temperature detected by a thermistor (not shown) of an indoor unit It is the rotation speed command value.

(1. Power module)

The power module 10 includes an inverter circuit 11, a device short-circuit protection means 12, and an inverter driving circuit 13. [

The inverter circuit 11 has a some switching element (not shown), and switches on / off of each switching element according to the PWN signal input from the inverter drive circuit 13, and drives a predetermined | prescribed three-phase alternating voltage motor. Output to (M). Then, the three-phase AC current according to the three-phase AC voltage flows into the motor M to generate the rotating magnetic field.

As the switching element of the inverter circuit 11, for example, an IGBT can be used.

The element short-circuit protection means 12 compares the current detection value inputted from the current detector 20 with a predetermined element short-circuit protection threshold value and outputs a stop command And outputs a signal to the inverter driving circuit 13. [

In addition, the processing of the element short circuit protection means 12 is executed without interposing a microcomputer.

The inverter drive circuit 13 applies a PWM signal (Pulse Width Modulation: pulse width modulation) to each switching element (not shown) of the inverter circuit 11 in accordance with a drive signal input from the drive signal generator 44 Signal). Further, when the stop command signal is inputted from the element short-circuit protection means 12, the inverter drive circuit 13 stops outputting the PWM signal.

(2. inverter control means)

The inverter control means (control means) 40 includes a motor current reproducing section 41, a speed command section 42, an overcurrent judging section 43, and a drive signal generating section 44. In addition, the processing of the inverter control means 40 is executed by a microcomputer (or via a microcomputer). The microcomputer includes an electronic circuit (not shown) such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) and various interfaces, reads a program stored in the ROM, And the CPU executes various processes.

The motor current reproducing section 41 reproduces a current flowing through the motor M (hereinafter referred to as a motor current) based on the detection signal detected by the current detector 20 and amplified by the amplifier 30 , And outputs it to the overcurrent judging section (43).

The speed command unit 42 receives the three-phase AC command voltage and the PWM frequency to be applied to the motor M based on the motor current input from the motor current reproducing unit 41 and the rotation speed command value? And outputs the calculated command value to the drive signal generating section 44.

The overcurrent judging section 43 compares the motor current inputted from the motor current reproducing section 41 with an overcurrent threshold value (another threshold value) stored in the microcomputer. When the motor current exceeds the overcurrent threshold value, And outputs a stop command signal to the signal generating section 44. The details of the overcurrent threshold value will be described later.

The drive signal generating section 44 generates a drive signal on the basis of the command value input from the speed command section 42 and outputs it to the inverter drive circuit 13. [ When the above-described stop command signal is input from the overcurrent judging unit 43, the drive signal generating unit 44 stops the generation of the drive signal in accordance with the command.

The determination process performed by the overcurrent determining unit 43 and the determination process performed by the device short-circuit protection unit 12 will be described below in order.

Incidentally, the overcurrent judging section 43 judges whether or not an actual abnormality (such as a step-out of the motor M, etc.) occurs after a predetermined number of msec or more has elapsed after detecting the above- I do. On the other hand, the device short-circuit protection means 12 performs a judgment process on the occurrence of an actual abnormality (short circuit of the inverter circuit 11, etc.) after elapse of several microseconds.

&Lt; Process of overcurrent judging unit >

As described above, the overcurrent judging unit 43 compares the motor current inputted from the motor current regenerating unit 41 with the overcurrent threshold value stored in the microcomputer so that the motor current exceeds the overcurrent threshold value (another threshold value) The processing of the drive signal generating section 44 is stopped.

The processing of the overcurrent determining section 43 is executed by a microcomputer (not shown). Therefore, the overcurrent determining section 43 can make a determination of high accuracy using a complex calculation formula. The calculation time of the microcomputer required for the determination processing performed in the present embodiment is 10 microseconds to several hundred microseconds.

The time Δtp from the detection of the overcurrent in the inverter circuit 11 by the current detector 20 to the stop of the operation of the inverter circuit 11 by the inverter control means 40 is as follows.

That is, the time? Tp is the time? Tp1 until the signal from the current detector 20 is input to the inverter control means 40 and the drive signal generation unit 44 (Tp2) until the inverter circuit 11 is actually turned off, and the time [Delta] tp3 until the inverter circuit 11 is actually turned off upon receiving a stop of the drive signal of the inverter control means 40, .

? Tp =? Tp1 +? Tp2 +? Tp3 (1)

Here, the current detector 20 and the current detector 20 to the inverter control means 40, the inverter control means 40 to the inverter circuit 11, and the inverter circuit 11 Called hardware circuit that does not interpose a microcomputer. Therefore, the times? Tp1 and? Tp3 until the signals from the current detector 20 are transmitted to the inverter control means 40 are several microseconds.

On the other hand, the inverter control means 40 executes a process from the input of the detection signal from the current detector 20 to the output of the stop command signal to the inverter driving circuit 13 by the microcomputer (not shown) , And it takes time from 10 microseconds to several hundred microseconds. Then, the time DELTA tp shown in the above-mentioned (formula 1) is also 10 mu sec to several hundred mu sec.

Therefore, the processing of the overcurrent judging section 43 using a microcomputer is suitable for judging a characteristic that takes longer than several milliseconds until the influence of the abnormality is detected after detection of abnormality (for example, as described above) .

For example, it is suitable for the determination processing by the overcurrent judging section 43 using a microcomputer, and it is possible to carry out the step-out protection of the motor M, the protection of the winding temperature of the motor M, the protection of the motor M, Temperature protection of the compressor (not shown), over-temperature protection of the compressor (not shown), pressure protection of the compressor, and the like. Since these characteristics take several msec or more until the abnormality occurs due to the electrical time constant, the heat capacity, or the like, it is possible to sufficiently cope with the processing using a microcomputer.

In this determination processing, control information such as the amplitude and phase of the motor current, the amplitude and phase of the motor-applied voltage, the DC voltage value and current value input to the inverter circuit 11, and the like can be used.

(Not shown), an outside temperature thermistor (not shown), a frosting thermistor (not shown), a discharge temperature thermistor (not shown), a human detection sensor (not shown) Sensor information acquired from a thermopile (not shown) or the like may be used.

In the present embodiment, as an example of the determination process by the overcurrent determining section 43, the motor M detects the preliminary tune (that is, the increase of the current input from the current detector 20) ) Is stopped will be described.

As described above, the synchronous motor rotates by sucking the rotor (permanent magnet) by the rotating magnetic field generated by the alternating current. However, there is a case where the PWM signal input from the inverter driving circuit 13 and the rotation of the motor M are lost in synchronization with an overload or a sudden change in the speed, and the synchronizing operation is interrupted.

Here, the deviation between the applied voltage and the motor induced voltage becomes large immediately before the demarcation occurs in the motor (M). For example, when voltage and current phase control is performed by vector control, the motor current increases by taking several hundred milliseconds before the motor M is removed.

Therefore, the overcurrent judging section 43 compares the motor current value with a predetermined overcurrent judging threshold value (another threshold value) stored in advance, and when the motor current value exceeds the overcurrent judging threshold value, (44). Thereby, the motor driving apparatus 100 can stop the driving of the motor M immediately when it detects the step-out (preliminary).

The overcurrent determination threshold value may be a predetermined constant value or the overcurrent determining section 43 may calculate the optimum overcurrent determination threshold value based on a difference between the voltage applied to the motor M and the phase of the induced voltage .

2 (a) is a flowchart showing the flow of processing performed by the overcurrent protection determination section. In the following description, the case where the ON / OFF operation of the switching element of the inverter circuit 11 in response to the PWM signal from the inverter driving circuit 13 is simply referred to as &quot; driving of the switching element &quot; do. It is also assumed that the switching element is driven at the start of the flowchart shown in Fig. 2 (a).

In step S101, the overcurrent determining section 43 determines whether or not a predetermined time [Delta] tp _A has elapsed from the start of the process. The predetermined time? Tp _A is the cycle time of the microcomputer executing the processing of the overcurrent determining section 43 and is a preset value.

When the predetermined time? Tp _A has elapsed from the start of the process (S101? Yes), the process of the overcurrent determining section 43 proceeds to step S102. On the other hand, when the predetermined time? Tp _A has not elapsed from the start of the process (S101? No), the overcurrent determining section 43 repeats the processing of the step S101.

In step S102, the overcurrent determining section 43 determines whether or not the motor current value I _M input from the motor current regenerating section 41 is larger than a predetermined overcurrent threshold value I _E (another threshold value).

If the motor current value I _M is larger than the overcurrent threshold value I _E (Yes in S102), the process of the overcurrent determining section 43 proceeds to step S103. On the other hand, when the motor current value I _M is equal to or lower than the overcurrent threshold value I _E (S102? No), the process of the overcurrent determining section 43 returns to the start.

In step S103, the overcurrent determining section 43 stops driving the switching element. As a result, power supply to the motor M is stopped, and the motor M is stopped.

&Lt; Process of short-circuit protection means >

Fig. 2 (b) is a flowchart showing the flow of processing performed by the element short-circuit protection means. It is assumed that the switching element of the inverter circuit 11 is driven at the time of starting the flow chart.

In step S201, the element short-circuit protection means 12 judges whether or not a predetermined time? T _B has elapsed from the start of the processing. Further, the predetermined time △ t _B is the cycle time of the device short circuit protection means (12), a preset value.

When the predetermined time? T _B has elapsed from the start of the processing (S201? Yes), the processing of the element short circuit protection means 12 proceeds to step S202. On the other hand, when the predetermined time? T _B has not elapsed from the start of the process (S201? No), the element short circuit protection means 12 repeats the processing of step S201.

In step S202, the element short circuit protection means 12 judges whether or not the current detection value I _S inputted from the current detector 20 is larger than the element short circuit protection threshold value I _D.

If the current detection value I _S is larger than the device short-circuit protection threshold value I _D (Yes in S202), the processing of the element short-circuit protection means 12 proceeds to step S203. On the other hand, when the current detection value I _S is equal to or smaller than the device short-circuit protection threshold value I _D (S202? No), the process of the device short-circuit protection means 12 returns to the start.

In step S203, the element short-circuit protection means 12 outputs a stop command signal to the inverter driving circuit 13. [ When the stop command signal is received from the element short-circuit protection means 12, the switching element of the inverter driving circuit 13 is stopped, and as a result, the driving of the motor M is also stopped.

The driving stopping process of the switching device based on the determination result of the overcurrent determining section 43 and the driving stopping process of the switching device based on the determination result of the device short-circuit protection section 12 are executed independently. For example, when the stop process by the device short-circuit protection means 12 is executed earlier than the stop process by the overcurrent judgment unit 43, the motor M is stopped by the stop command outputted from the device short- Stops the signal by triggering.

<Effect>

According to the motor driving apparatus 100 according to the present embodiment, a comparative judgment process using a microcomputer is performed with respect to a characteristic (such as a step-out) that takes a time of several msec or more from the detection of an abnormal tone , And stops the driving of the switching element as needed. Therefore, complicated calculations can be performed by the microcomputer using the control information and the sensor information about the motor (M), so that highly accurate determination processing can be performed.

In other words, since the timing at which the arithmetic operation is performed is later than the timing at which the arithmetic processing of the microcomputer ends, the driving of the motor M can be stopped before the arcing occurs.

As described above, the time from the detection of the overcurrent by the element short-circuit protection means 12 to the issuance of the stop command signal to the inverter driving circuit 13 is the time required in the hardware circuit not including the microcomputer For example, 3 [micro] sec). Thereby, when the current detected by the current detector 20 exceeds the element short-circuit protection threshold value I _D , the stop command by the element short-circuit protection means 12 is supplied to the motor potato protection overcurrent judging unit 46 Is outputted earlier than the stop command by the stop command. Therefore, breakdown of the switching element by the short-circuit current can be reliably prevented.

3 is an explanatory diagram schematically showing a temporal change of the motor current when a short-circuit current flows in the switching element. When the motor current suddenly rises from the time t ₀ shown in FIG. 3 and the current value I ₁ exceeding the short-circuit protection threshold value I _D is detected at the time t ₁ by the current detector 20 I think about it.

The device absolute rating (I _R ) shown in Fig. 3 is a value that is set in advance as a current value that should not exceed the motor current even at a moment.

In this case, the driving of the switching element by a from the time t ₁ sigan △ t _q (= number μsec) after the time element short-circuit protection means 12 to t ₂ is stopped. As a result, after the time t ₂ can be reduced sharply, and the motor current (refer to a solid line arrow in Fig. 3), the motor current is prevented from reaching the element absolute rating (I _R). Further, the time period Δt _q is shorter than the time (short-circuit tolerance) that a switching element such as an IGBT can withstand a short-circuit current.

On the other hand, when the microcomputer performs the process of determining the short-circuit protection threshold value, the driving of the switching element is stopped at the time t ₃ after the time Δt _p (= 10 μsec to several hundred μsec) from the time t ₁ , The motor current I ₃ exceeding the absolute value of the element I _R flows (refer to a broken line arrow in FIG. 3), leading to the destruction of the switching element.

According to the motor drive apparatus 100 of the present embodiment, the element short-circuit protection means 12 is provided outside the inverter control means 40, which is a microcomputer, and the determination processing is executed without interposing a microcomputer. As a result, the rise of the current at the time of short circuit of the inverter circuit 11 can be grasped quickly, and the driving of the switching element can be stopped during the rise, thereby reliably preventing the breakdown of the switching element.

In addition, since the electronic circuit handles weak current, it is easily affected by noise. In the motor driving apparatus 100 according to the present embodiment, the driving of the switching element can be stopped quickly in a time of several microseconds. Therefore, it is possible to set the element short-circuit protection threshold value to a value at which it is possible to judge that the short circuit is surely generated in the inverter circuit 11. [ That is, since the element short-circuit protection threshold value can be raised to near the absolute value of the element absolute value, malfunction due to noise (stopping of the motor M) can be eliminated.

<< 2nd embodiment >>

The motor drive apparatus 100A according to the second embodiment is provided with the motor potato protection overcurrent determining section 46 instead of the overcurrent determining section 43 described in the first embodiment and further includes the motor winding temperature detector 50 And a motor potentiometer protection threshold value setting unit 45. The other points are the same as those of the first embodiment. Therefore, other portions will be described, and redundant portions will not be described.

&Lt; Configuration of Motor Drive Apparatus >

4 is a system configuration diagram including a motor driving device.

The motor winding temperature detector (winding temperature detecting means) 50 detects the motor winding temperature of the motor M and outputs it to the motor potentiometer protection threshold value setting unit 45 momentarily.

The motor potentiostat protection threshold value setting section 45 sets a potentiostat protection threshold value (another threshold value) for preventing the permanent magnet potatoes in accordance with the motor winding temperature inputted from the motor winding temperature detector 50. The process performed by the motor potentiometer protection threshold value setting unit 45 will be described later

The motor potato protection overcurrent determining section 46 determines whether or not the motor M is powered by the motor current based on the motor current input from the motor current reproducing section 41 and the potato protection threshold value input from the motor potentiating protection threshold value setting section 45. [ It is determined whether or not an overcurrent exceeding the protection threshold value is flowing. When it is judged that the overcurrent exceeding the potato protection threshold value is flowing to the motor M, the motor potato protection overcurrent determining section 46 stops the processing of the drive signal generating section 44. [

&Lt; Case of low-temperature potato characteristic >

(1. Setting of motor potato protection threshold)

In the following description, the motor current value at the time when the potato is generated in the permanent magnet of the motor (M) is referred to as &quot; motor potato current &quot;.

When permanent magnets are exposed to an excessive inverse magnetic field, the magnetism is weakened by causing potatoes, and the characteristics of the magnets deteriorate. That is, when an excessive current flows in the permanent magnet used in the motor M, the potato is generated by the inverse magnetic field generated by the current. Therefore, it is necessary to prevent an overcurrent larger than the motor potato current from flowing into the motor M.

The motor potentiometer protection threshold value setting section 45 sets the motor potentiostat protection threshold value based on the detected temperature inputted from the motor winding temperature detector 50 to the potato protection threshold value (another threshold value), which is a threshold value for stopping the driving of the switching element, And outputs it to the motor potato protection overcurrent judging section 46. [

In addition, the processing of the motor potato protection threshold value setting section 45 is executed by the microphone computer.

5 is a graph showing changes in element absolute ratings, motor potato current, motor potato protection threshold, and short-circuit protection threshold value for the motor winding temperature using a permanent magnet having a low-temperature potato characteristic.

As shown in Fig. 5, the permanent magnet having a low-temperature potato characteristic (for example, a ferrite magnet) has a lower motor potentiometer current value (that is, it becomes prone to demagnetization) as its temperature decreases.

Therefore, the motor potentiometer protection threshold value setting section 45 sets the motor potentiometer protection threshold value to become smaller as the motor winding temperature becomes lower.

Further, the motor potentiometer protection threshold value is set to be smaller than the value of the motor potentiometer current at any motor winding temperature. That is, in the example shown in Fig. 5, the temperature characteristic of the motor potato protection threshold value is represented by a plurality of line segments in order to simplify the processing of the microcomputer software.

(2. Setting of short-circuit protection threshold value)

The element short-circuit protection means 12 sets the element short-circuit protection threshold value I _D for preventing the switching element of the inverter circuit 11 from short-circuiting to a predetermined value lower than the element absolute rating I _R 5). In addition, the element short-circuit protection threshold value I _D is set as a constant value not depending on the temperature of the motor winding.

Also in this embodiment, as in the first embodiment, the element short-circuit protection means 12 executes processing without interposing a microcomputer, and when the motor current exceeds the element short-circuit protection threshold value I _D , .

5, the motor potentiometer protection value I _M is smaller than the short-circuit protection threshold value I _D by a predetermined value? I1 (= I _D -I _O ) in the region where the motor winding temperature T ₀ or more, As shown in FIG. This is because, when the motor current exceeds the short-circuit protection threshold value I _D , the short-circuit protection means 12 stops driving the inverter circuit 11 before the motor-over-current protection overcurrent judging unit 46 .

In addition, in the other temperature region (for example, a low temperature region), the motor potentiometer protection threshold value is higher than the device short-circuit protection threshold value (for example, May be set to be equal to or less than the threshold value.

<In the case of high-temperature potato characteristics>

6 is a graph showing changes in absolute value of the motor winding temperature, motor potato current, motor potato protection threshold value, and short circuit protection threshold value for a motor using permanent magnets having high-temperature potato characteristics.

As shown in Fig. 6, the permanent magnet having a high-temperature potato characteristic (for example, a neodymium magnet) has a smaller motor potato current value (i.e.

Therefore, the motor potentiometer protection threshold value setting section 45 sets the potentiometer protection threshold value to be small as the motor winding temperature becomes high.

In addition, in the example shown in Fig. 6, the high temperature characteristic of the motor potentiometer protection threshold value is represented as a plurality of line segments, and the motor winding temperature T ₂ In the following area, the motor potential protection threshold value is set to a predetermined value higher by ΔI2 (= I ₂ -I _D ) than the device temperature protection threshold value I _D. And, in the region where the motor winding temperature is higher than the temperature T ₃ , the element short-circuit protection threshold value is set to be larger than the motor potentiometer protection threshold value.

The permanent magnet having the high-temperature potato characteristic is not limited to the neodymium magnet, but may be another rare earth magnet.

<Operation of Motor Drive Apparatus>

The motor potato protection threshold value setting unit 45 sets the characteristic motor potentiometer protection threshold value shown in Fig. 5 according to the motor winding temperature inputted from the motor winding temperature detector 50, and sets the motor potato protection over- And outputs the information of the threshold value every moment.

The motor potato protection overcurrent determining section 46 compares the motor current input from the motor current regenerating section 41 with the motor potentiometer protection threshold value input from the motor potentiometer protection threshold value setting section 45. [

When the motor current exceeds the motor potentiometer protection threshold value, the motor potato protection overcurrent judging unit 46 stops the process of the drive signal generating unit 44. As a result, the driving of the switching element is stopped, the supply of electric power to the motor M is stopped, and the motor M is stopped.

On the other hand, when the motor current is equal to or less than the motor potentiometer protection threshold value, the motor potentiator overcurrent judging section 46 repeats the above comparison processing every predetermined time.

<Effect>

The motor driving apparatus 100A according to the present embodiment can be applied to a motor M provided with a permanent magnet having a low temperature potato characteristic such as a ferrite magnet or a high temperature potato characteristic such as a neodymium magnet, Can be made less than the motor potato current, and the potato of the permanent magnet can be reliably prevented. That is, with respect to the potato characteristics with a relatively large time constant, the microcomputer stops the driving of the switching element after performing the determination processing with high precision by the control of the microcomputer.

As a result, as shown in Fig. 5 and Fig. 6, it is possible to finely define the motor potato protection threshold value according to the motor winding temperature. That is, since the maximum current according to the motor winding temperature can be flowed to the motor winding while preventing the motor M from being demagnetized, the capability of the motor M can be maximized.

On the other hand, when the circuit must be shut off in a short time, such as when the switching element is short-circuited, the driving of the switching element is stopped by a circuit (device short-circuit protection means 12) not interposing a microcomputer.

As a result, the permanent magnet of the motor M can be prevented from being demagnetized, and the switching element of the inverter circuit 11 can be adequately protected.

Further, the correlation between the motor winding temperature and the motor potato protection threshold value can be determined by a plurality of parameters. That is, only by changing these constants according to the driven motor M, it is possible to cope with a plurality of kinds of permanent magnets by using the same microcomputer software, and development of microcomputer software can be simplified. The temperature characteristic of the motor potentiometer protection threshold value is represented by at least one curve (including a straight line), and the predetermined temperature T ₀ In the above area, the motor potentiometer protection threshold value is set as a constant value I _M (see Fig. 5). Therefore, the processing load of the microcomputer can be reduced.

&Quot; Third Embodiment &

The motor driving apparatus 100B according to the third embodiment is provided with the element temperature protection overcurrent judging unit 48 instead of the overcurrent judging unit 43 described in the first embodiment and further includes the element temperature detector 60, And a temperature protection threshold value setting unit 47 are provided. The rest is the same as the first embodiment. Therefore, the description of other portions will be omitted.

&Lt; Configuration of Motor Drive Apparatus >

7 is a system configuration diagram including a motor drive device.

The device temperature detector (device temperature detecting means) 60 detects the temperature of the switching device provided in the inverter circuit 11, and outputs the detected device temperature to the device temperature protection threshold value setting unit at a time.

The device temperature protection threshold value setting unit 47 sets the device temperature protection threshold value (another threshold value) according to the device temperature input from the device temperature detector 60. [ The process performed by the device temperature protection threshold value setting unit 47 will be described later.

The device temperature protection overcurrent judging section 48 judges whether or not the motor current I is supplied to the motor M based on the motor current inputted from the motor current reproducing section 41 and the device temperature protection threshold value inputted from the device temperature protection threshold value setting section 47 It is determined whether or not an overcurrent exceeding the device temperature protection threshold value is flowing. If an overcurrent exceeding the device temperature protection threshold value flows to the motor M, the device temperature protection overcurrent judging unit 48 stops the process of the drive signal generating unit 44. [

In addition, the processing of the element temperature protection threshold value setting section 47 is executed by the microcomputer.

On the other hand, the element short-circuit protection means 12 performs the same processing as that of the first embodiment. That is, when the current detected by the current detector 20 exceeds the short-circuit protection threshold value, the element short-circuit protection means 12 must quickly stop the inverter circuit 11, and in the circuit not interposing the microcomputer, Stop driving. As a result, when a short circuit occurs in the inverter circuit 11, the driving of the switching element is quickly stopped, and the breakdown of the switching element can be reliably prevented.

8 is a graph showing changes in element absolute ratings, element short circuit protection threshold value, temperature breakdown current value, element temperature protection threshold value, and current limit threshold value of the switching element of the inverter circuit.

 As shown in Fig. 8, the element short-circuit protection threshold value is set to a current value lower than the element absolute rating. The device temperature breakdown current value is a current value that leads to breakdown of the switching device when a current equal to or greater than the current value flows. The device temperature protection threshold value is set as a current value smaller than the device temperature breakdown current value by a predetermined value. The current limit threshold value is a threshold value for decelerating the motor M, and is set as a current value smaller than the device temperature protection threshold value by a predetermined value.

As shown in Fig. 8, a region which is equal to or higher than the device temperature protection threshold value and lower than the device temperature breakdown current value is set as the &quot; stop region &quot;. Further, an area that is equal to or higher than the current limit threshold value and is lower than the device temperature protection threshold value is set as the &quot; deceleration area &quot;. Further, an area less than the current limit value is set as the &quot; normal area &quot;

9 is a flowchart showing the flow of operation of the device temperature protection overcurrent judging unit.

In step S301, the element temperature protection overcurrent judging section 48 judges whether or not a predetermined time? T _C has elapsed from the start of the processing. The predetermined time? T _C is the cycle time of the microcomputer for executing the processing of the element temperature protection overcurrent judging section 48, and is a preset value.

When the predetermined time? T _C has elapsed from the start of the process (S301? Yes), the process of the device temperature protection overcurrent determining section 48 proceeds to step S302. On the other hand, when the predetermined time? T _C has not elapsed from the start of the process (S301? No), the device temperature protection overcurrent determining section 48 repeats the process of step S301.

In step S302, the element temperature protection overcurrent determining section 48 determines whether or not the motor current value I _M input from the motor current regenerating section 41 is larger than the element temperature protection threshold value I _T. If the motor current value I _M is larger than the device temperature protection threshold value I _T (Yes in S302), the process of the device temperature protection overcurrent judging unit 48 proceeds to step S303. On the other hand, when the motor current value I _M is equal to or lower than the device temperature protection threshold value I _T (S302? No), the process of the device temperature protection overcurrent judging unit 48 proceeds to step S304.

In step S303, the element temperature protection overcurrent determining section 48 stops the processing of the drive signal generating section 44. [ That is, the device temperature protection overcurrent judging unit 48 stops driving the switching device.

Incidentally, when the motor current is below the device short-circuit protection threshold value and is larger than the device temperature protection threshold value, the short-circuit protection means 12 constituted by a hardware circuit does not operate.

In step S304, the element temperature protection overcurrent judging section 48 judges whether or not the motor current value I _M is larger than the current limit threshold value I _L. If the motor current value I _M is larger than the current limit threshold value I _L (S304? Yes), the process of the device temperature protection overcurrent determining section 48 proceeds to step S305. On the other hand, when the motor current value I _M is equal to or less than the current limit threshold value I _L (S304? No), the processing of the element temperature protection overcurrent determining section 48 returns to the start.

In step S305, the element temperature protection overcurrent determining section 48 outputs a predetermined command signal to the drive signal generating section 44 in order to decelerate the motor M. [

<Effect>

According to the motor driving apparatus 100B of the present embodiment, the comparative judgment processing using a microcomputer is performed with respect to the temperature characteristic of the switching element, which takes a time of several msec or more from detection of abnormality And stops the driving of the switching element as necessary. Since the device temperature protection threshold value used in performing the comparison process is determined according to the device temperature input from the device temperature detector 60, the overcurrent can be determined with high accuracy.

Further, since the switching element has a predetermined heat capacity, the driving of the motor M can be stopped before the switching is broken due to the temperature rise.

The element temperature protection threshold value setting unit 47 is provided with a predetermined operation expression for associating the element temperature protection threshold value with the element temperature and the element temperature protection threshold value by one or more curves (including a straight line) It is set in advance. Therefore, since the setting can be changed simply by setting the integer of the calculation formula to an appropriate value, the software of the microcomputer can be made the same for other types of inverter circuits 11, and the stage of product development can be simplified .

8), the element temperature protection overcurrent judging section 48 outputs a predetermined command signal to the drive signal generating section 44 to decelerate the motor M . Thereby, the current flowing into the switching element is reduced, and the driving of the motor (M) can be maintained while lowering the temperature of the switching element.

&Quot; Fourth Embodiment &

The motor driving apparatus 100C according to the fourth embodiment is different from the third embodiment in that the motor winding temperature detector 50 and the motor potato protection threshold value setting unit 45 and the motor potato protection overcurrent determining unit 46, And the rest is the same as the third embodiment. Therefore, the other parts will be described, and the description of the parts overlapping with the third embodiment will be omitted.

10 is a system configuration diagram including a motor driving device.

The motor winding temperature detector (winding temperature detecting means) 50 detects the winding temperature of the motor M and outputs it to the motor potentiometer temperature protection threshold value setting unit 45 momentarily.

The motor potato temperature protection threshold value setting unit 45 sets the potato protection threshold value according to the motor winding temperature inputted from the motor winding temperature detector 50 and outputs the threshold value to the motor potato protection overcurrent judging unit 46.

The motor potato protection overcurrent determination section 46 stops the processing of the drive signal generation section 44 when the motor current exceeds the potato protection threshold value, based on the motor current and the potato protection threshold value.

The processes executed by the motor winding temperature detector 50, the motor potentiometer protection threshold value setting section 45 and the motor potato protection overcurrent judging section 46 are the same as those in the second embodiment, and thus their detailed description is omitted .

The processing of the inverter control means 40C is executed via the microcomputer. That is, the potentiometer protection threshold value is finely set according to the temperature characteristics of the switching element and the permanent magnet temperature characteristics (low-temperature potantial characteristic or high-temperature characteristic characteristic) of the motor M, Stop driving.

On the other hand, the processing of the element short-circuit protection means 12 is carried out without interposing a microcomputer. Thereby, the element short-circuit protection means 12 stops driving the inverter circuit 11 in several microseconds after detecting that the motor current exceeds the short-circuit protection threshold value.

<Effect>

According to the motor driving apparatus 100C of the present embodiment, the processing of the inverter control means 40C is executed by using a microcomputer. Therefore, an appropriate device temperature protection threshold value is set in accordance with the temperature of the switching element input from the device temperature detector 60, and an appropriate potato protection threshold value is set according to the temperature of the motor winding input from the motor winding temperature detector 50 Can be set. That is, it is possible to drive the motor M by the maximum current while preventing the temperature breakdown of the switching element and the demagnetization of the permanent magnet of the motor M.

Therefore, according to the motor driving apparatus 100C of the present embodiment, the performance of the switching element and the performance of the motor M can be sufficiently utilized and the reliability can be improved.

In addition, by performing the processing by the element short-circuit protection means 12 without interposing a microcomputer, it is possible to stop the drive of the inverter circuit 11 by a few microseconds after detecting the overcurrent. This makes it possible to reliably prevent the switching element provided in the inverter circuit 11 from being destroyed by the overcurrent.

"Variations"

As described above, the motor driving apparatus according to the present invention has been described with respect to each embodiment, but the embodiment of the present invention is not limited to these descriptions, and various modifications can be made.

For example, in the third embodiment and the fourth embodiment described above, the element temperature detector 60 detects the temperature of the switching element, but the present invention is not limited to this. That is, instead of the element temperature detector 60 (see FIG. 7), power module temperature detecting means (not shown) for detecting the surface temperature of the power module 10 (see FIG. 7) It may be detected indirectly.

In this case, the correlation between the temperature of the switching element and the device temperature protection threshold is substituted by the correlation between the surface temperature of the power module 10 including the inverter circuit 11 and the device temperature protection threshold value.

That is, the inverter control means 40 sets the device temperature protection threshold value in response to the temperature input from the power module temperature detection means, and stops driving the switching device when the motor current exceeds the device temperature protection threshold value .

As a result, the temperature of the switching element can be surely protected even in the form of using the power module 10, and the mounting structure of the temperature detector (power module temperature detecting means) and the lead-out structure of the signal line are simplified, .

7) for detecting the temperature of the surface of the substrate (not shown) on which the inverter circuit 11 is mounted, and the temperature of the switching element (not shown) May be indirectly detected.

In this case, the inverter control means 40 sets the element temperature protection threshold value in response to the temperature input from the substrate temperature detection means, and stops driving the switching element when the motor current exceeds the device temperature protection threshold value .

As a result, the temperature of the device can be surely protected even in the form of using the substrate temperature detecting means, and the attachment structure of the temperature detector and the lead-out structure of the signal line can be simplified, and the manufacturing cost can be reduced.

In addition, instead of the element temperature detector 60 (see FIG. 7), heat dissipation fin temperature detection means (not shown) for detecting the temperature of the heat dissipation fin (not shown) for cooling the inverter circuit 11 is provided, and the switching element The temperature may be indirectly detected.

In this case, the inverter control means 40 sets the device temperature protection threshold value in response to the temperature input from the heat radiation fin temperature detection means, and when the motor current exceeds the device temperature protection threshold value, Stop driving

In each of the above-described embodiments, the description has been given of the case where all the switching elements of the inverter circuit 11 are IGBTs. However, the present invention is not limited to this.

That is, at least one of the switching elements of the inverter circuit 11 is made of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and the correlation of the element temperature protection threshold value is set based on the temperature of the MOSFET You can.

That is, the MOSFET has a larger loss (that is, heat generated) as compared with the IGBT when the current increases. Particularly, among MOSFETs, MOSFETs having a super junction structure have high efficiency when the current value is small. However, when the current value is large, the MOSFET has a large loss.

Therefore, the temperature of the MOSFET-type switching element is detected by the element temperature detector 60, and the element temperature protection threshold value setting unit 47 sets the element temperature protection threshold value corresponding to the temperature. Thus, temperature protection of the switching element (including prevention of thermal runaway of the MOSFET) can be reliably performed, and efficient operation can be performed in normal operation.

In the above-described second and fourth embodiments, the motor winding temperature detector 50 detects the winding temperature of the motor M, but the present invention is not limited to this. That is, a compressor (not shown) driven by a motor M is provided, and in place of the motor winding temperature detector 50 (see Fig. 4), an enclosure temperature detection for detecting the temperature of the outside of the compressor The winding temperature of the motor M may be indirectly detected by means (not shown).

That is, the correlation between the winding temperature of the motor M and the protection threshold value of the motor is replaced with a correlation between the protection temperature and the outer protection temperature of the compressor

In this case, the inverter control means 40 sets a potentiostat protection threshold value corresponding to the temperature inputted from the above-mentioned outside temperature detecting means, and stops the driving of the switching element when the motor current exceeds the potentiometer protection threshold value.

Thus, motor potato protection is performed on the basis of the correlation between the outside temperature of the compressor and the motor potentiometer protection threshold value, so that the potato protection of the motor M can be appropriately performed. Further, as compared with the case where the temperature detector is provided inside the compressor which becomes the high pressure, the attachment structure of the temperature detector (outer temperature detection means) and the lead-out structure of the signal line are simplified, and the manufacturing cost can be reduced.

Therefore, it is possible to provide a fluid compression system capable of appropriately preventing potatoes of permanent magnets provided in the motor (M).

Instead of the above motor winding temperature detector 50 (see FIG. 4), discharge pipe temperature detecting means (not shown) for detecting the temperature of a discharge pipe (not shown) of a compressor (not shown) driven by a motor (Not shown) may indirectly detect the winding temperature of the motor M.

 In this case, the inverter control means 40 sets a potentiometric protection threshold value corresponding to the temperature inputted from the discharge pipe temperature detecting means, and when the motor current exceeds the potentiometric protection threshold value, Stop.

As a result, the potato protection of the motor M can be reliably performed, and the attachment structure of the temperature detector (discharge pipe temperature detection means) and the lead-out structure of the signal line can be simplified, and the manufacturing cost can be reduced.

The winding temperature of the motor M is estimated based on the outer temperature of the compressor input from the outer temperature detection means (not shown) for detecting the outer temperature of the compressor and the current detection value input from the current detector 20 It may be

The winding temperature of the motor M is higher than the outer temperature of the compressor due to heat generation (motor loss) accompanying the flow of the current. Therefore, how much higher the winding temperature of the motor M is with respect to the outer temperature of the compressor is corrected by using the current detection value input from the current detector 20 as a parameter.

In this case, the inverter control means 40 calculates the motor loss, which is the amount of heat generated in the motor M, based on the outer temperature input from the outer temperature detection means and the current value input from the current detector 20, And estimates the winding temperature of the motor M in response to the motor loss. That is, the winding temperature of the motor M is corrected using the current detection value input from the current detector 20 as a parameter.

In addition, the inverter control means 40 estimates a potentiostat protection threshold value corresponding to the estimated motor winding temperature, and stops driving the switching element when the motor current exceeds the potentiostat protection threshold value.

As a result, the winding temperature of the motor M can be reproduced with good accuracy, the operable range of the motor M can be widened, and the potato protection of the motor M can be performed more reliably.

On the basis of the discharge pipe temperature of the compressor inputted from the discharge pipe temperature detecting means (not shown) for detecting the discharge pipe temperature of the compressor and the current detection value inputted from the current detector 20, May be estimated. In this case as well, the winding temperature of the motor M is corrected using the current detection value input from the current detector 20 as a parameter.

Further, since the process of the inverter control means 40 is the same as the above case, the description is omitted.

In each of the above-described embodiments and modifications, the motor M may be a DC brushless motor using permanent magnets. Further, a compressor (not shown) may be a compressor of a high-pressure chamber driven by the DC brushless motor.

Thus, by using a DC brushless motor as the compressor motor M, high energy efficiency can be realized. It is also possible to provide a fluid compression system capable of properly protecting the switching elements of the inverter circuit 11 and reliably preventing the potato of the motor M. [

In addition, as a compressor (not shown), a compressor of a low-pressure chamber driven by a DC brushless motor is used and installed in an outdoor unit (not shown) instead of the above-described motor winding temperature detector 50 (Not shown) installed in the indoor unit (not shown) and the indoor temperature detecting means (not shown) may be used.

In this case, during the heating operation, the temperature of the windings of the motor (M) is indirectly detected by the conception detecting means provided in the outdoor unit. The inverter control means 40 sets the potentiometer protection threshold value in response to the temperature input from the conception detecting means, and stops the driving of the switching element when the motor current exceeds the potentiometer protection threshold value.

On the other hand, during the cooling operation, the temperature of the winding of the motor (M) is indirectly detected by the indoor temperature detecting means provided in the indoor unit. The inverter control means 40 sets the potentiometer protection threshold value in response to the temperature input from the indoor temperature detecting means, and stops the driving of the switching element when the motor current exceeds the potentiometer protection threshold value.

That is, the inverter control means 40 uses the thermal correlation between the winding temperature of the motor M and the fusing temperature of the heat exchanger, or the thermal correlation between the winding temperature of the motor M and the room temperature, .

As a result, the potato of the motor M can be surely prevented, and the attachment structure of the temperature detector (the implantation detection means and the room temperature detection means) and the lead-out structure of the signal line can be simplified, and the manufacturing cost can be reduced

Further, the air conditioner (not shown) may include the fluid compression system described above. In this case, the compressor including the motor M is installed in the outdoor unit.

As a result, it is possible to reliably protect the switching elements and the potentiometer of the motor (M), and to provide an air conditioner with high reliability. Further, even when the air conditioner is required to have a large capacity in an environment of a low temperature or a high temperature where the air load is large, the air conditioner can maximize its air conditioning capability.

In each of the above-described embodiments, the permanent magnet type synchronous motor is used as the motor M. However, the present invention is not limited to this. That is, the above-described embodiments can be similarly applied to a wire-wound synchronous motor, a reluctance motor, and other synchronous motors.

In each of the above embodiments, the alternating-current voltage input from the alternating-current power supply 200 is converted into a direct-current voltage by the converter circuit 300 and the switching element of the inverter circuit 11 is driven to generate a predetermined alternating- The case of conversion is explained, but the present invention is not limited to this. For example, a DC voltage may be input to the inverter circuit 11 from a battery (DC power source: not shown).

Further, the DC voltage may be actively controlled by using an active circuit (not shown).

100, 100A, 100B, 100C Motor drive unit
10 power module
11 Inverter circuit
12 Devices short-circuit protection
13 Inverter drive circuit
20 Current detector (current detection means)
30 amplifier
40, 40A, 40B, 40C Inverter control means (control means)
41 Motor current reproduction section
42 Speed command section
43 Overcurrent judging unit (control means)
44 drive signal generating unit (control means)
45 Motor potato protection threshold value setting unit (control means)
46 Motor potato protection Overcurrent judgment (control means)
47 Device temperature protection threshold value setting unit (control means)
48 Device temperature protection Overcurrent judgment (control means)
50 Motor winding temperature detector (winding temperature detection means)
60 device temperature detector (device temperature detecting means)
200 AC power supply
300 converter circuit
M motor

Claims (19)

An inverter circuit having a switching element for converting a DC voltage inputted from a DC power supply into an AC voltage and a current detecting means for detecting a DC current supplied to the inverter circuit, A motor drive apparatus for driving a motor by electric power,
Control means for controlling ON / OFF of the switching element;
And device short-circuit protection means for stopping the driving of the switching element when the current value input from the current detection means exceeds a short-circuit protection threshold value for preventing a short circuit in the inverter circuit,
The control means estimates a motor current flowing into the motor from a current value input from the current detecting means, and the motor current is related to temperature protection of the switching element and / or potato protection of the motor. Executing a process of stopping the driving of the switching element when the other current threshold value is exceeded,
The processing of the element short-circuit protection means is executed without interposing a microcomputer,
And the processing of said control means is executed via a microcomputer. The method of claim 1,
And winding temperature detecting means for directly or indirectly detecting the winding temperature of the motor,
Wherein the other current threshold value includes a potato protection threshold value set based on a potato characteristic of a magnet of the motor,
Wherein the temperature characteristic of the potato protection threshold value has a temperature range in which the short protection threshold value is greater than the potato protection threshold value,
The control means sets the potato protection threshold value in accordance with the winding temperature input from the winding temperature detection means and stops the driving of the switching element when the motor current exceeds the potato protection threshold value Characterized in that the motor drive device. The method of claim 1,
And a device temperature detecting means for directly or indirectly detecting the temperature of the switching device,
The other current threshold value includes a device temperature protection threshold value set based on an element characteristic of the switching element,
Wherein the temperature characteristic of the device temperature protection threshold value has a temperature range where the short-circuit protection threshold value is larger than the device temperature protection threshold value,
Wherein the control means sets the element temperature protection threshold value corresponding to the temperature of the switching element inputted from the element temperature detection means, and when the motor current exceeds the element temperature protection threshold value, And stops the driving of the motor. The method of claim 1,
Winding temperature detecting means for directly or indirectly detecting the winding temperature of the motor and device temperature detecting means for directly or indirectly detecting the temperature of the switching device,
Wherein the other current threshold value includes a potentiometric protection threshold value set based on a potentiometric characteristic of a magnet of the motor and a device temperature protection threshold value set based on an element characteristic of the switching element,
Wherein the temperature characteristic of the potato protection threshold value has a temperature range in which the short protection threshold value is greater than the potato protection threshold value,
Wherein the temperature characteristic of the device temperature protection threshold value has a temperature range where the short-circuit protection threshold value is larger than the device temperature protection threshold value,
The control means sets the potentiometric protection threshold value in accordance with the winding temperature input from the winding temperature detection means and sets the device temperature protection threshold value corresponding to the temperature of the switching element input from the element temperature detection means, And stops the driving of the switching element when the motor current exceeds at least one of the potato protection threshold value and the device temperature protection threshold value. The method according to claim 2 or 4,
The magnet of the motor has a potato characteristic that the value of the potato current becomes smaller as the temperature of the magnet becomes lower,
Wherein the control means sets the potato protection threshold value to be smaller as the winding temperature inputted from the winding temperature detection means becomes lower, based on the potato characteristics of the magnet. The method of claim 5, wherein
Wherein the magnet of the motor is a ferrite magnet. The method according to claim 2 or 4,
The magnet of the motor has a potato characteristic that the value of the potato current becomes smaller as the temperature of the magnet becomes higher,
Wherein the control means sets the potentiometer protection threshold value to be smaller as the winding temperature inputted from the winding temperature detection means becomes higher, on the basis of the potentiometer characteristic of the magnet. The method of claim 7, wherein
Wherein the magnet of the motor is a rare earth magnet. The method according to claim 3 or 4,
The element temperature detecting means for indirectly detecting the temperature of the switching element is a power module temperature detecting means for detecting a surface temperature of the power module including the inverter circuit,
The control means sets the element temperature protection threshold value corresponding to the temperature inputted from the power module temperature detection means and stops the driving of the switching element when the motor current exceeds the element temperature protection threshold value And the motor drive device. The method according to claim 3 or 4,
The element temperature detecting means for indirectly detecting the temperature of the switching element is substrate temperature detecting means for detecting the surface temperature of the substrate on which the inverter circuit is mounted,
The control means sets the device temperature protection threshold value corresponding to the temperature input from the substrate temperature detection means and stops the driving of the switching device when the motor current exceeds the device temperature protection threshold value And the motor drive device. The method according to claim 3 or 4,
The device temperature detection means for indirectly detecting the temperature of the switching element is a heat radiation fin temperature detection means for detecting the temperature of the heat radiation fin for cooling the inverter circuit,
The control means sets the element temperature protection threshold value corresponding to the temperature input from the heat radiation fin temperature detection means and stops driving the switching element when the motor current exceeds the element temperature protection threshold value And the motor drive device. The method according to claim 3 or 4,
At least one of the switching elements of the inverter circuit is a MOSFET,
The device temperature detecting means detects the temperature of the MOSFET and outputs it to the control means,
Wherein the control means sets the element temperature protection threshold value in accordance with the temperature of the MOSFET input from the element temperature detection means. A motor drive device according to claim 2 or 4,
And a compressor driven by the motor,
The winding temperature detection means for indirectly detecting the winding temperature of the motor is an outer temperature detection means for detecting the outer temperature of the compressor,
The control means sets the potentiometer protection threshold value in accordance with the temperature inputted from the outer frame temperature detection means and stops the driving of the switching element when the motor current exceeds the potato protection threshold value Lt; / RTI &gt; A motor drive device according to claim 2 or 4,
And a compressor driven by the motor,
The winding temperature detecting means for indirectly detecting the winding temperature of the motor is a discharge pipe temperature detecting means for detecting a discharge pipe temperature of the compressor,
The control means sets the potato protection threshold value corresponding to the temperature inputted from the discharge pipe temperature detecting means and stops the driving of the switching element when the motor current exceeds the potato protection threshold value Characterized in that the fluid compression system comprises: A motor drive device according to claim 2 or 4,
And a compressor driven by the motor,
The winding temperature detecting means for indirectly detecting the winding temperature of the motor is an outer temperature detecting means for detecting an outer temperature of the compressor and the current detecting means for detecting a DC current supplied to the inverter circuit,
Wherein,
A motor loss, which is a heat quantity generated in the motor, is calculated based on a temperature input from the outer housing temperature detection means and a current value input from the current detection means,
Estimating a winding temperature of the motor in accordance with the calculated motor loss,
Setting the potato protection threshold value in correspondence with the estimated winding temperature,
And stop the driving of the switching element when the motor current exceeds the potato protection threshold. A motor drive device according to claim 2 or 4,
And a compressor driven by the motor,
The winding temperature detecting means for indirectly detecting the winding temperature of the motor includes discharge pipe temperature detecting means for detecting a discharge pipe temperature of the compressor and the current detecting means for detecting a direct current supplied to the inverter circuit,
Wherein,
Calculating a motor loss which is a quantity of heat generated in the motor based on a temperature input from the discharge pipe temperature detection means and a current value input from the current detection means,
Estimating a winding temperature of the motor in accordance with the calculated motor loss,
Setting the potato protection threshold value in correspondence with the estimated winding temperature,
And stop the driving of the switching element when the motor current exceeds the potato protection threshold. The method of claim 13,
The motor is a direct current brushless motor using permanent magnets,
Wherein the compressor is a compressor of a high-pressure chamber driven by the DC brushless motor. A motor drive device according to claim 2 or 4,
And a compressor of a low-pressure chamber driven by the motor,
The motor is a DC brushless motor using a permanent magnet,
During the heating operation, the winding temperature of the motor is indirectly detected by the frost detection means provided in the outdoor unit,
The temperature of the winding of the motor is indirectly detected by the room temperature detecting means provided in the indoor unit during the cooling operation,
Wherein,
The control means sets the potentiometric protection threshold value corresponding to the temperature input from the frost detection means or the room temperature detection means and stops the driving of the switching element when the motor current exceeds the potato protection threshold value Lt; / RTI &gt; An air conditioner comprising the fluid compression system according to claim 13.

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