JP2006271048A - Motor driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable motor driving device of vector control or sensorless control type, of which a module can be made small, for detecting a motor current at high precision. <P>SOLUTION: An inverter circuit 3 converts a DC power to an AC power to drive a motor 4. A current detecting means 5 detects the output current of the inverter circuit 3. A control means 6 controls the inverter circuit 3 for driving the motor 4. A current detecting module, in which a shunt resistor 50 is integrated with a current signal amplifying means 51, constitutes the current detecting means 5, realizing a small and high-reliability motor driving device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor drive device, and more particularly to current detection means thereof.

Conventionally, this type of motor driving device detects the current flowing through a plurality of shunt resistors connected to the emitter terminal of the lower arm transistor of the inverter circuit and performs vector control or sensorless control of the motor (for example, Patent Document 1).
JP 2003-9539 A

  However, the conventional motor current detection method applies a current signal flowing through the shunt resistor to the A / D converter via the level shift circuit, and the wiring between the shunt resistor and the A / D converter becomes long. Current detection error increases due to switching noise, and if excessive negative switching noise is input, the A / D converter built in the microcomputer composed of CMOS malfunctions, and worst, latch-up causes A There was a problem that the / D converter was destroyed.

  The present invention solves the above-mentioned conventional problems, and connects a current amplifying means between an A / D converter and a shunt resistor so that the shunt resistor and the current amplifying means are integrated into an A / D module. To prevent destruction and malfunction of the converter and to reduce the resistance value of the shunt resistor by using the current amplifying means, so that the module can be miniaturized, and a small and highly reliable motor driving device can be realized. It is the purpose.

  In order to solve the above-described conventional problems, the motor driving apparatus of the present invention converts DC power into AC power by an inverter circuit, drives the motor by the inverter circuit, and outputs the output current of the inverter circuit to the shunt resistor and the current signal. It is detected by current detection means comprising amplification means, and the inverter circuit is PWM controlled by a signal from the current detection means to drive the motor, and the shunt resistor and current signal amplification means are integrated into a current detection module.

  The motor driving device of the present invention detects the current flowing through the inverter circuit by the current detecting means that modularizes the shunt resistor and the current signal amplifying means, and controls the motor connected to the output of the inverter circuit. And the current signal amplification means are shortened to reduce the effect of switching noise, and the A / D converter malfunction due to switching noise and the destruction of the microcomputer incorporating the A / D converter can be prevented. Thus, a highly reliable motor drive device can be realized.

  The first invention is an inverter circuit that converts DC power into AC power, a motor driven by the inverter circuit, a shunt resistor that detects an output current of the inverter circuit, and a current that amplifies the current signal of the shunt resistor. A current detection means comprising a signal amplification means; and a control means for driving the motor by controlling the inverter circuit according to an output signal of the current detection means, wherein the current detection means comprises a current detection module. A small, highly reliable motor drive device that can constitute a current detection module with high detection accuracy and high reliability, can prevent malfunction and destruction of the A / D converter built in the microcomputer, Can be realized.

  According to a second invention, in the first invention, the inverter circuit is constituted by a three-phase full bridge inverter circuit comprising six transistors and a diode, and the current detecting means is a lower arm transistor of the three-phase full bridge inverter circuit. A plurality of current detection terminals respectively connected to the negative potential side terminal, a plurality of shunt resistors connected to the current detection terminal, and a plurality of current signal amplification means for detecting current signals of the plurality of shunt resistors. A common terminal commonly connected to the negative potential side terminals of the plurality of shunt resistors, a plurality of output signal terminals for outputting output signals of the plurality of current signal amplifying means, and a DC power supply terminal of the plurality of current signal amplifying means And by using a plurality of shunt resistors and a plurality of current signal amplification means as one current detection module. Out enables miniaturization and reliability means, it is possible to realize a motor drive device having the high control means reliable compact.

  According to a third invention, in the first invention, the inverter circuit is constituted by a three-phase full bridge inverter circuit comprising six transistors and a diode, and the current detecting means is a lower arm transistor of the three-phase full bridge inverter circuit. A plurality of current detection terminals respectively connected to the negative potential side terminal, a plurality of shunt resistors connected to the current detection terminal, and a plurality of current signal amplification means for detecting current signals of the plurality of shunt resistors. A plurality of overcurrent detection means for detecting respective overcurrents of the plurality of shunt resistors, the plurality of current signal amplifying means, DC power supply terminals of the plurality of overcurrent detection means, and the plurality of overcurrent detection means. An overcurrent signal output terminal, and the output signals of the plurality of overcurrent detection means are OR-connected to output one overcurrent output signal. By using a plurality of shunt resistors, a plurality of current signal amplification means, and a plurality of overcurrent detection means as one current detection module, the current detection accuracy of the current detection means is improved, the reliability is improved, and the size is reduced. Since the output signals of multiple overcurrent detection means are OR-connected to output one overcurrent output signal, the number of terminals of the current detection module can be reduced and the size can be reduced. The destruction of the magnets and the transistors of the inverter circuit can be prevented, and a small and highly reliable motor driving device can be realized.

  According to a fourth aspect of the present invention, there is provided an inverter circuit for converting DC power into AC power, a motor driven by the inverter circuit, a shunt resistor for detecting an output current of the inverter circuit, and a current for amplifying a current signal of the shunt resistor. A current detection unit configured by a signal amplification unit; and a control unit configured to control the inverter circuit by an output signal of the current detection unit to drive the motor. The current detection unit is configured to amplify the current signal from a non-inverting amplifier. A first input resistor is connected between the current detection terminal of the shunt resistor and the non-inverting input terminal of the non-inverting amplifier, and a second input resistance is connected between the non-inverting input terminal and the DC power supply terminal. Is set so that the product of the voltage dividing ratio of the first input resistance and the second input resistance and the amplification factor of the non-inverting amplifier is approximately 0.5, The DC voltage of the A / D converter that performs A / D conversion on the output signal of the inverting amplifier is made equal to the DC voltage of the DC power supply terminal that connects the second input resistor. Since a non-inverting amplifier can be constituted by an operational amplifier, the DC power source of the current detecting means can be simplified and reduced in price, and an inexpensive, small and highly reliable motor driving device can be realized.

(Embodiment 1)
FIG. 1 is a block diagram of a motor drive device according to the first embodiment of the present invention. In FIG. 1, AC power is applied from an AC power source 1 to a rectifier circuit 2 and converted into DC power to constitute a DC power source. A DC power is converted into three-phase AC power by an inverter circuit 3 to drive a motor 4. In the rectifier circuit 2, capacitors 21a and 21b are connected in series to the DC output terminal of the full-wave rectifier circuit 20, and a connection point of the capacitors 21a and 21b is connected to one terminal of the AC power supply input to constitute a DC voltage doubler circuit. The voltage applied to the inverter circuit 3 is increased to reduce the current, thereby reducing the circuit loss. The current detection means 5 is connected to the negative voltage side of the inverter circuit 3, and the output current of the inverter circuit 3, that is, each phase current of the motor 4 is detected by detecting the current flowing through the lower arms of the three phases of the inverter circuit 3. Then, the control means 6 controls the drive current of the motor 4 to control the rotation.

  The current detecting means 5 is a so-called three-shunt system, and is connected to the emitter terminal of the lower arm transistor of the inverter circuit 3 (referred to as a shunt resistor 50 hereinafter). And a current signal amplifying means 51 for detecting the current flowing through each of the shunt resistors 50a, 50b, 50c.

  The current input terminals 52a, 52b, and 52c of the shunt resistors 50a, 50b, and 50c are respectively connected to the emitter terminal of the lower arm transistor of the inverter circuit 3, and the ground side common terminal 53 is connected to the negative voltage side terminal L2 of the rectifier circuit 2. To do. The output terminals 54 a, 54 b and 54 c of the current signal amplifying means 51 are connected to the input terminal of the A / D converter of the control means 6, and the DC power supply terminal 55 of the current signal amplifying means 51 is connected to the A / D of the control means 6. Connected to the DC power supply voltage terminal (Vcc) of the converter.

  The current detection means 5 is called three-shunt type current detection, and detects inverter circuit output current, that is, motor phase current, and performs vector control or position sensorless sine wave drive. The current corresponding to the motor current is detected at the timing when the antiparallel diode of the arm is turned on. The three-shunt method enables current detection corresponding to the motor phase current by securing the conduction time and dead time of the lower arm transistor, and enables low-cost current detection by omitting the DC current transformer. In the so-called one-shunt method, when the carrier frequency is high or the modulation degree becomes large, an area where current cannot be detected appears. Therefore, the three-shunt method can detect current more quickly and accurately.

  The control means 6 is constituted by a microcomputer or a high-speed processor with a built-in A / D converter such as a digital signal processor (abbreviated as DSP), and the current output signal from the current detection means 5 is converted into a digital signal by the A / D converter. Then, the inverter circuit 3 is PWM-controlled to control the motor current to perform sensorless driving or vector control.

  Further, by connecting the common connection point C of the shunt resistors 50a, 50b and 50c, that is, the common terminal 53 to the ground potential and connecting the common terminal 53 to the ground terminal (GND) of the control means 6, the current detection means 5 and the control means. By making each ground potential of each circuit 6 common, the DC power supply of the circuit can be reduced and the number of parts can be reduced.

  By integrating the shunt resistor 50 and the current signal amplifying means 51 into a current detection module, the wiring between the shunt resistor 50 and the current signal amplifying means 51 can be shortened, and current detection errors due to wiring impedance are almost eliminated. Can do. Furthermore, the number of components can be reduced by modularization, or the gain of the current signal amplification means can be finely adjusted.

  FIG. 2 is a detailed circuit diagram of the inverter circuit 3, which is constituted by a three-phase full-bridge inverter circuit comprising six transistors and diodes. Here, one U-phase arm 30A of the three-phase arm will be described. A parallel connection body of an upper arm transistor 31a1 made of an insulated gate bipolar transistor (hereinafter abbreviated as IGBT) and an antiparallel diode 32a1, and a lower arm made of IGBT. The parallel connection body of the transistor 31a2 and the antiparallel diode 32a2 is connected in series, the collector terminal of the upper arm transistor 31a1 is connected to the positive potential terminal L1 of the DC power supply, and the emitter terminal of the upper arm transistor 31a1 is the output to the motor 4 Connected to the terminal U, the emitter terminal Nu of the lower arm transistor 31a2 is connected to the negative potential side terminal L2 of the DC power source comprising the rectifier circuit 2 through the shunt resistor 50a constituting the current detecting means 5.

  The upper arm transistor 31a1 is driven by the upper arm gate drive circuit 33a1 in accordance with the upper arm drive signal Up, and the lower arm transistor 31a2 is subjected to on / off switching control by the lower arm gate drive circuit 33a2 in accordance with the lower arm drive signal Un. The upper arm gate drive circuit 33a1 incorporates an RS flip-flop circuit that is set and reset by a differential signal, turns on the upper arm transistor 31a1 at the rise of the upper arm drive signal Up, and rises at the fall of the upper arm drive signal Up. The arm transistor 31a1 is turned off. The lower arm gate drive circuit 33a2 does not need an RS flip-flop circuit and does not incorporate it.

  The gate application voltage of the IGBT needs 10 to 15V. When the lower arm transistor 31a2 is turned on, the bootstrap capacitor 36a is charged from the + terminal B1 of the 15V DC power supply through the bootstrap resistor 34a and the bootstrap diode 35a. Therefore, the upper arm transistor 31a1 can be switched on / off by the energy stored in the bootstrap capacitor 36a. Similarly, the bootstrap capacitor 36a is charged when the lower arm antiparallel diode 32a2 is turned on.

  By applying an overcurrent signal to the cutoff signal terminal Of of the inverter circuit 3, the U-phase, V-phase, and W-phase lower arm transistors of the inverter circuit 3 are instantaneously turned off.

  The V-phase arm 30B and the W-phase arm 30C are similarly connected. The emitter terminals Nv and Nw of the lower arm transistors of each arm are connected to the shunt resistors 50b and 50c constituting the current detecting means 5, and the shunt resistors 50b and 50c are connected. Is connected to the DC power source negative potential terminal L2. If the lower arm transistor is configured by an IGBT or a power MOSFET, switching control can be performed by controlling the gate voltage. Therefore, the voltage of the shunt resistor connected to the emitter terminal in the case of IGBT and the source terminal in the case of power MOSFET is 1 V or less. If the resistance value is selected, the on / off switching control can be performed by voltage control with almost no effect on the switching operation, and the inverter circuit output current can be detected by detecting the voltages veu, vev, and vew of the shunt resistors 50a, 50b, 50c. In other words, the motor current can be detected.

  FIG. 3 is a detailed circuit diagram showing an embodiment of the current signal amplifying means of the three-shunt type current detecting means 5 according to the present invention. The AC current signals detected by the shunt resistors 50a, 50b and 50c are non-inverted. The signal is converted and amplified by an amplifier, and level-converted to a DC voltage level that can be detected by an A / D converter incorporated in a processor such as a microcomputer.

  Since the current signal amplifying means 51a, 51b, 51c are the same circuit, the U-phase current signal amplifying means 51a will be described. The peak value of the voltage veu generated in the shunt resistor 50a corresponds to the U-phase output current of the inverter circuit 3, and the shunt resistance voltage veu changes between positive and negative with respect to the ground potential of the current signal amplification means. Since an A / D converter built in a microcomputer or the like operates at a predetermined DC voltage, it is necessary to shift the amplification level so that the center value of the DC voltage is zero and changes with respect to the center value. In other words, the motor current signal is set to change within the input dynamic range of the A / D converter.

  The capacitor 500a is connected in parallel with the shunt resistor 50a, the first input resistor 501a and the second input resistor 502a are connected in series with the shunt resistor 50a, and the second input is connected to the DC power supply terminal 55 of the current signal amplifying means 51a. The input resistor 502a is pulled up. The connection point of the first input resistor 501a (resistance value R2) and the second input resistor 502a (resistance value R1) is connected to the non-inverting input terminal of the operational amplifier 503a, and between the output terminal and the inverting input terminal of the operational amplifier 503a. Is connected to a feedback resistor 504a (resistance value R4), and a resistor 505a (resistance value R3) is connected between the inverting input terminal and the ground potential to constitute a non-inverting amplifier. Assuming that the resistance value of the shunt resistor 50a is Ro, the voltage veu of the shunt resistor 50a is the product of the resistance value Ro and the current Iu (veu = Ro × Iu), which is the difference between the first input resistor 501a and the second input resistor 502a. Assuming that the pressure ratio k is k = R2 / (R1 + R2) and the feedback amplification factor K is K = R4 / R3, the output voltage vau of the current signal amplifying means 51a is expressed by Equation 1.

  Here, if the product of the voltage division ratio k and the feedback amplification factor K, that is, k × K = 0.5, the current Iu is centered on 1/2 of the DC power supply voltage Vcc of the A / D converter. Is converted to a voltage signal corresponding to.

  For example, when the voltage dividing ratio k = 0.1, the feedback amplification factor K = 5, the shunt resistance value Ro = 0.2Ω, and the voltage Vcc = 5V applied to the DC power supply terminal, the output voltage of the current signal amplifying means 51a is vau = 0. .9 × Iu + 2.5. That is, when the DC voltage of the A / D converter is 5 V, the center value 2.5 V corresponds to 0 A, and the dynamic range can detect a current up to about ± 2.5 A with respect to ± 2.5 V. .

  The resistor 506a and the diodes 507a and 508a are connected for overvoltage protection of the A / D conversion circuit.

  FIG. 4 is a circuit diagram showing another embodiment of the current signal amplifying means according to the present invention, in which the current signal is amplified by an inverting amplifier to convert the voltage level, and only the portion of the U-phase current signal amplifying means 51a1 is shown. ing.

  The circuit connection is a part of the embodiment shown in FIG. 3, in which the first input resistor 501a is connected to the shunt resistor 50a, the second input resistor 502a is connected to the negative power source Ve, and the operational amplifier 503a is connected. Is used as an inverting amplifier. The grounding resistor 505a shown in FIG. 3 can be omitted. At this time, the feedback amplification factor K is obtained by dividing the feedback resistor 504a (R4) by the first input resistor 501a (R2), and the relational expression between the shunt resistance voltage drop veu and the output voltage vau is expressed by Equation 2.

  Here, the ratio of the feedback resistor 504a and the second input resistor 502a is set to R4 / R1 = 0.5, and the DC voltage absolute value of the negative power supply Ve is set to the power supply voltage (dynamic range) of the A / D converter. If equal, the shunt resistance voltage is amplified and level-converted so as to change up and down with respect to the center value of the DC power supply voltage Vcc of the A / D converter. For example, when Ve = −5V, R4 = 10 kΩ, R1 = 20 kΩ, and R2 = 2 kΩ, the output signal vau is expressed by vau = 2.5−5 × veu. When the shunt resistance resistance value is 0.2Ω and the current is Iu, vau = 2.5−Iu.

  As described above, the current signal amplifying means 51a using the non-inverting amplifier described in FIG. 3 is equal to the DC power supply voltage to be pulled up and the DC power supply voltage (Vcc) of the A / D converter. If the product (k × K) of the voltage dividing ratio k and the feedback amplification factor K of the second input resistor connected to the input resistor in a pull-up connection is approximately 0.5, the DC power supply voltage (A / D converter circuit) The level can be converted to the center value of Vcc).

  The current signal amplifying means 51a1 using the inverting amplifier described in FIG. 4 makes the negative power supply voltage absolute value equal to the DC voltage of the A / D converter, and the ratio of the feedback resistance and the resistance pull-down connected to the negative power supply (Ve). Should be set to approximately 0.5.

  As described above, the current detection means of the present invention can be easily and inexpensively detected by a small number of components and a single power supply operational amplifier. In addition, since the current signal of the shunt resistor is amplified by the operational amplifier, the current can be detected even with a low-resistance shunt resistor, the loss of the shunt resistor can be reduced, and the current detection module can be downsized by reducing the shunt resistor. Can do. Further, since the wiring of the shunt resistor and the operational amplifier can be shortened, almost no current detection error due to the wiring can be eliminated. Furthermore, since the current signal amplifying means serves as a buffer, high-speed switching noise is not directly input to the A / D converter, so that there is no possibility that the A / D converter malfunctions or latches up. In addition, the non-inverting amplifier shown in FIG. 3 operates with a single power source, so that the DC power source can be simplified.

(Embodiment 2)
The second embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a block diagram of a motor drive device according to the second embodiment of the present invention. By adding an overcurrent detection means 56 to the current detection means 5A, the current flowing through the shunt resistor 50 is detected. The current of the inverter circuit 3A or the motor 4 is detected and the overcurrent is detected, the current signal is level-shifted, and the overcurrent signal Fo is output. Other configurations are the same as those of the first embodiment, and detailed description thereof is omitted.

  The current detection means 5A is added to the shunt resistor 50, the current signal amplification means 51 and various terminals described in FIG. 1 in the first embodiment, and an overcurrent detection means 56, an overcurrent output signal terminal 57, and an overcurrent. A setting terminal 58 is provided, and when the signal Vref corresponding to the overcurrent setting value is applied to the overcurrent setting terminal 58 by the control means 6A and a current exceeding the overcurrent setting value flows to the shunt resistor, the overcurrent detection means 56 The overcurrent signal Fo is applied from the overcurrent output signal terminal 57 to the abnormal signal interrupt terminal IRQ of the control means 6A, and the control means 6A turns off the control signal GC of the inverter circuit 3A by the abnormal interrupt signal.

  Further, the overcurrent signal Fo is also applied to the cutoff signal terminal Of of the inverter circuit 3A similar to that explained in FIG. 2, and the output of the inverter circuit 3A is instantaneously stopped. Therefore, the cutoff function and control means of the inverter circuit 3A It is protected from overcurrent by a double protection function consisting of a cutoff function by a 6A abnormal interrupt signal. For the overcurrent caused by the overload of the motor 4 or the overcurrent caused by the step-out, there is no problem with the interruption response speed from the abnormal interrupt signal of the control means 6A, but in the case of the short circuit of the upper and lower arms of the inverter circuit 3A An interruption response speed within microseconds is required, and the inverter circuit 3A is directly interrupted by the overcurrent signal Fo.

  FIG. 6 is a detailed circuit diagram of the current detection means 5A in the second embodiment of the present invention. The current signal amplifying means 51a is the same as that described in the first embodiment with reference to FIG. The overcurrent detection means 56 detects an overcurrent by detecting the terminal voltage of the shunt resistor 50. The overcurrent detection means 56a, each of which includes a current of each of the shunt resistors 50a, 50b, 50c, is constituted by a voltage comparator. Detected by 56b and 56c, the respective output terminals of the overcurrent detection means 56a, 56b and 56c are OR-connected, and one of the overcurrent signals is output to the overcurrent output signal terminal 57.

  The overcurrent detection means 56a adds a voltage signal veu to the inverting input terminal of the voltage comparator 560a via an integrating circuit composed of a resistor 561a connected to the shunt resistor 50a and a capacitor 562a, and the non-inverting input of the voltage comparator 560a. When the voltage signal veu becomes higher than the set voltage signal Vref as compared with the set voltage signal Vref applied to the terminal, the output terminal voltage decreases to Lo. The output stage of the voltage comparator 560a is normally composed of an open collector transistor, and the output resistor 563a can be easily pulled up to form a logical OR circuit. The overcurrent detection means 56b and 56c are similarly connected, and an OR circuit can be configured by directly connecting the output terminals. Further, since the set voltage signal Vref is applied to each non-inverting input terminal, when any one of the shunt resistors 50a, 50b, and 50c becomes equal to or higher than the set voltage signal Vref, the overcurrent of the active Lo is applied to the overcurrent output signal terminal 57. The signal Fo is output.

  As described above, the current detection means 5A constitutes a current detection module in which a plurality of shunt resistors, a plurality of operational amplifiers for current signal amplification, and a plurality of voltage comparators for overcurrent detection are integrated. As a result, the wiring between the shunt resistor and the operational amplifier and the wiring between the shunt resistor and the voltage comparator are shortened to reduce not only the pattern wiring impedance but also the noise induced in the wiring pattern. This makes it possible to reduce malfunctions caused by the above and to accurately detect current and overcurrent.

  FIG. 7 is an external view of the current detection module according to the present invention excluding the outer coat. The shunt resistors 50a, 50b, and 50c and the current signal amplifying means 51 are configured on the module substrate 5a, and a plurality of operational amplifiers 503a and the like are included in one package. The operational amplifier module 503A incorporating the above circuit, the overcurrent detection means 56, the voltage comparator module 560A incorporating a plurality of circuits such as the voltage comparator 560a in one package, and other resistors, capacitors, etc., are mounted. Input terminals 52a, 52b, and 52c, a common terminal 53, output terminals 54a, 54b, and 54c, a DC power supply terminal 55, an overcurrent signal output terminal 57, and an overcurrent setting terminal 58 are provided.

  If the shunt resistors 50a, 50b, and 50c are formed of thin film resistors other than metal plate resistors such as printing resistors, a low-cost current detecting means can be formed, but there is a risk that overcurrent flows and burns. However, the possibility of burning the thin film resistor can be eliminated by coating the exterior with a flame-retardant resin or by covering the printing resistance with a non-flammable plate.

  When the current input terminals 52a, 52b, and 52c are as close as possible to the common terminal 53 and the common terminal 53 is close to the operational amplifier module 503A and the voltage comparator module 560A, the wiring is shortened to prevent malfunction and improve current detection accuracy. be able to. Further, as shown in FIG. 7, by configuring the current detection module so as to be mounted in the vertical direction, the mounting density can be increased, and the area of the inverter circuit and its control board can be reduced.

  As described above, the present invention is a current detection module in which the current detection means is integrally configured by the shunt resistor, the current signal amplification means, and the overcurrent detection means, and the wiring impedance can be reduced. Current can be detected, and the control board can be miniaturized by improving the component mounting density, and a low-cost and highly reliable motor drive device can be realized.

  As described above, the motor drive device of the present invention converts DC power into AC power by the inverter circuit, drives the motor by the inverter circuit, and outputs the output current of the inverter circuit to the current composed of the shunt resistor and the current signal amplification means. It is detected by the detection means, and the inverter circuit is PWM controlled by the signal of the current detection means to drive the motor, and the shunt resistor and the current signal amplification means are integrated into a current detection module. Since accurate current detection is possible, not only can the shunt resistor be downsized by the operational amplifier, but also malfunction of the A / D converter and latch-up can be prevented, and a compact, high-accuracy and highly reliable current detection means can be configured. It can be applied to most motor drive devices that perform vector control or sensorless control. Motor driving device, a pump motor driving device, a washing machine motor driving device can be applied to an air conditioner or a refrigerator heat pump motor driving device.

The block diagram of the motor drive device in the 1st Embodiment of this invention The circuit diagram which shows the inverter circuit of the motor drive device by this invention Circuit diagram of current signal amplification means by non-inverting amplifier of motor drive device according to the present invention Circuit diagram of current signal amplifying means by inverting amplifier of motor driving device according to the present invention The block diagram of the motor drive device in the 2nd Embodiment of this invention The circuit diagram of the electric current detection means of the motor drive device in the 2nd Embodiment of this invention Outline drawing of current detection module according to second embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Inverter circuit 4 Motor 5 Current detection means 6 Control means 50 Shunt resistance 51 Current signal amplification means 56 Overcurrent detection means

Claims (4)

An inverter circuit that converts DC power into AC power, a motor driven by the inverter circuit, a shunt resistor that detects an output current of the inverter circuit, and a current signal amplification unit that amplifies the current signal of the shunt resistor. A motor drive device comprising: current detection means; and control means for driving the motor by controlling the inverter circuit according to an output signal of the current detection means, wherein the current detection means is constituted by a current detection module. The inverter circuit is composed of a three-phase full-bridge inverter circuit composed of six transistors and a diode, and the current detecting means is a plurality of currents respectively connected to the negative potential side terminals of the lower arm transistors of the three-phase full-bridge inverter circuit. A detection terminal; a plurality of shunt resistors connected to the current detection terminal; a plurality of current signal amplifying means for detecting current signals of the plurality of shunt resistors; and a negative potential side terminal of the plurality of shunt resistors. 2. The motor driving apparatus according to claim 1, further comprising: a common terminal connected in common; a plurality of output signal terminals for outputting output signals of the plurality of current signal amplifying means; and a DC power supply terminal for the plurality of current signal amplifying means. . The inverter circuit is composed of a three-phase full-bridge inverter circuit composed of six transistors and a diode, and the current detecting means is a plurality of currents respectively connected to the negative potential side terminals of the lower arm transistors of the three-phase full-bridge inverter circuit. A detection terminal, a plurality of shunt resistors connected to the current detection terminal, a plurality of current signal amplifying means for detecting current signals of the plurality of shunt resistors, and an overcurrent of each of the plurality of shunt resistors. A plurality of overcurrent detection means for detecting; a plurality of current signal amplifying means; a DC power supply terminal for the plurality of overcurrent detection means; and an overcurrent signal output terminal for the plurality of overcurrent detection means. 2. The motor drive device according to claim 1, wherein the output signal of the overcurrent detection means is OR-connected to output one overcurrent output signal. An inverter circuit that converts DC power into AC power, a motor driven by the inverter circuit, a shunt resistor that detects an output current of the inverter circuit, and a current signal amplification unit that amplifies the current signal of the shunt resistor. A current detection means; and a control means for driving the motor by controlling the inverter circuit according to an output signal of the current detection means, wherein the current detection means constitutes the current signal amplification means means from a non-inverting amplifier, A first input resistor is connected between a current detection terminal of the shunt resistor and a non-inverting input terminal of the non-inverting amplifier; a second input resistor is connected between the non-inverting input terminal and a DC power supply terminal; 1 is set such that the product of the voltage dividing ratio of the input resistance of 1 and the second input resistance and the amplification factor of the non-inverting amplifier is approximately 0.5, The motor drive apparatus that is the DC voltage of the DC power supply terminals for connecting a DC voltage and the second input resistance of the A / D converter is equal to the force signal to convert A / D.