JP2009017674A - Inverters for motor-applied home appliances - Google Patents

Abstract

An inverter for a motor-applied home appliance capable of reliably detecting an abnormal voltage at a low cost is provided.
A microcomputer 40 for controlling a washing and drying machine incorporates A / D conversion circuits 50 and 51, and a DC power supply voltage supplied to an inverter circuit 33 via an input channel switching device 52 is applied to their input terminals. When the voltage signal VIN for monitoring is given and it is determined that the voltage signal is out of the normal range, the abnormal voltage detection signal is directly output to the emergency stop circuit 58 or 69 without passing through the CPU which is a part of itself. To do.
[Selection] Figure 1

Description

  The present invention relates to an inverter of a motor-applied home appliance that includes an inverter circuit that drives a motor used in the home appliance and a microcomputer that controls the inverter circuit.

  Patent Document 1 discloses a technique for protecting a circuit element by suppressing an abnormal high voltage generated by a motor when the motor is idling out of a state in which the motor is driven and controlled. Specifically, the DC power supply voltage supplied to the inverter circuit is divided and input to the voltage comparison circuit, and when the voltage comparison circuit detects the generation of a voltage exceeding a predetermined level, the upper arm constituting the inverter circuit A circuit for forcibly turning off the input part of the driver arranged corresponding to the switching element on the side and a circuit for forcibly turning on the input part of the driver arranged corresponding to the switching element on the lower arm side It is the composition provided with.

According to the above configuration, when the motor is idling at high speed due to malfunction of the control, a short circuit loop is formed between the motor winding and the lower arm side switching element of the inverter circuit, and the short circuit braking is applied. Energy generated in the winding can be consumed. Therefore, it is possible to prevent the high level regenerative voltage generated by the winding from flowing backward to the inverter circuit side and being damaged beyond the withstand voltage limit of the circuit components.
Japanese Patent Application Laid-Open No. 2002-101689

  However, the configuration of Patent Document 1 has the following problems. First, since the voltage comparison circuit and the circuit for forcibly turning on and off the driver are configured, it is necessary to separately mount components such as transistors and comparators on the substrate, which increases the circuit size and the cost. And reliability is also reduced. Second, since the circuit wiring length becomes long, malfunctions due to noise increase. In addition, the voltage comparison circuit is liable to malfunction due to the influence of switching noise in the inverter circuit.

  In addition, as a well-known technique for solving the same technical problem as in Patent Document 1, an abnormally high voltage is obtained by dividing a DC power supply voltage, A / D-converting and reading by a microcomputer, and processing the conversion result by software. Some determine abnormal low voltage. When an abnormally high voltage is determined, a protection operation by short-circuit braking control is performed as in Patent Document 1, and when an abnormally low voltage is determined, the operation of the inverter circuit is stopped and the output is turned off. In this case, since the A / D converter that is normally incorporated in the control microcomputer of the home appliance is used, a circuit component for determining the voltage is unnecessary. In addition, if a microcomputer program is set so as to perform determination based on a plurality of consecutive A / D conversion results, erroneous determination due to the influence of noise can be prevented.

  However, the above technology has a slow response speed from the time when the abnormal voltage occurs until the protection operation is executed.For example, when an abnormally high voltage occurs, the withstand voltage limit of the circuit component is reduced when the short-circuit braking is started. May exceed. Further, when a high level of noise occurs, it is assumed that the CPU of the microcomputer runs out of control. In this case, the protection operation against the abnormal voltage is not performed at all.

  This invention is made | formed in view of the said situation, The objective is to provide the inverter of the motor application household appliances which can detect an abnormal voltage reliably at low cost.

The inverter of the motor-applied home appliance of the present invention includes an inverter circuit that drives a motor for home appliances and a microcomputer that controls the inverter circuit.
The microcomputer is
An A / D conversion circuit is incorporated, and a voltage signal for monitoring a DC power supply voltage supplied to the inverter circuit is given to an input terminal of the A / D conversion circuit,
If it is determined that the voltage signal is out of the normal range, an abnormal voltage detection signal is output directly to an abnormal processing circuit for coping with the occurrence of the abnormal voltage without using a CPU that is a part of the abnormal voltage detection signal. A voltage detection circuit is provided.

  With such a configuration, since the abnormal voltage detection circuit is built in the microcomputer, the abnormal voltage can be detected without substantially increasing the number of circuit components, and the determination process can be performed quickly. Further, since the microcomputer performs ripple control or the like on the DC power supply voltage, the microcomputer is often configured to monitor the voltage by A / D conversion. Therefore, if the input terminal of the A / D conversion circuit and the input terminal of the abnormal voltage detection circuit are made common, an increase in the number of terminals is suppressed. Since the abnormal voltage detection signal is directly output to the abnormality processing circuit without going through the CPU, abnormal processing for dealing with the occurrence of abnormal voltage is also started quickly.

  According to the present invention, it is possible to reliably detect an abnormal voltage at a low cost, and it is possible to quickly execute a countermeasure when an abnormal voltage occurs.

(First embodiment)
A first embodiment in which the present invention is applied to a drum-type washing / drying machine will be described below with reference to FIGS. First, in FIG. 3 which shows the whole structure of the drum-type washing / drying machine (motor-applied home appliance) 1, a door 2 is provided at the center of the front surface of the outer box 1a which forms the outer shell of the washing / drying machine 1. An operation panel 3 having a large number of switches and a display unit (none of which are shown) is provided at the top. The door 2 opens and closes the laundry loading / unloading port 4 formed at the center of the front portion of the outer box 1a.

  A cylindrical water tank 5 is disposed inside the outer box 1a. The water tank 5 is arranged in a horizontal axis shape in which the axial direction is the front-rear direction (left-right direction in FIG. 3) and in an upwardly inclined shape, and is elastically supported by the elastic support device 6. A cylindrical drum 7 is disposed coaxially with the water tank 5 inside the water tank 5. The drum 7 functions as a shared tub for dehydration and drying in addition to washing, and a large number of small holes 8 (only a part of which is shown) are formed in the entire body, A plurality of (for example, three) baffles 9 (only one is shown) are provided on the inner periphery. The drum 7 is rotated forward and backward with a relatively short cycle during a washing operation (which is a concept including a rinsing operation), and is rotated forward and reverse with a relatively long cycle during a drying operation.

  The aquarium 5 and the drum 7 have openings 10 and 11 for putting in and out the laundry on the respective front surfaces, and the opening 11 of the drum 7 faces the opening 10 of the aquarium 5 from the inside. The opening 10 of the water tub 5 is connected to the laundry entrance / exit 4 in a watertight manner by a cylindrical bellows 12, and a balance ring 13 is provided around the opening 11 of the drum 7.

  A DC brushless motor (hereinafter simply referred to as a motor) 14 that rotationally drives the drum 7 is disposed on the back surface of the water tank 5. The motor 14 is of an outer rotor type, and the stator 15 is attached to the outer peripheral portion of the bearing housing 16 supported at the center of the back portion of the water tank 5. In the outer type rotor 17, a rotating shaft 18 fixed at the center is rotatably supported by a bearing housing 16 via a bearing 19. The front end portion of the rotating shaft 18 protruding from the bearing housing 16 is connected to the central portion of the back portion of the drum 7. That is, when the motor 14 is driven, the drum 7 connected to the rotating shaft 18 of the rotor 17 is rotated.

A water reservoir 20 is provided at the bottom of the water tank 5, a heater 21 for heating the washing water is disposed inside the water reservoir 20, and a drain hose 23 is disposed at the rear of the water reservoir 20 via a drain valve 22. Is connected.
A hot air generator 24 for drying operation is provided at the upper part of the water tank 5, and a heat exchanger 25 is provided at the back of the water tank 5. The hot air generator 24 includes a hot air heater 27 disposed in a casing 26, a fan 29 disposed in the casing 28, and a fan motor 31 that rotationally drives the fan 29 via a belt transmission mechanism 30. The casing 26 and the casing 28 are in communication with each other. A duct 32 is connected to the front portion of the casing 26, and the tip end portion of the duct 32 is arranged so as to protrude into the water tank 5 and face the opening 12 of the drum 7.

Here, warm air is generated by simultaneously driving the warm air heater 27 and the fan 29 in the warm air generating device 24, and the warm air is supplied into the drum 7 through the duct 32. The warm air supplied into the drum 7 heats the laundry in the drum 7 and removes moisture, and is discharged to the heat exchanger 25 side.
The heat exchanger 25 has an upper portion communicating with the inside of the casing 28 and a lower portion communicating with the inside of the water tank 5. Water is poured from the upper portion and flows down, thereby cooling and condensing water vapor in the air passing through the inside. It is a water-cooled type that dehumidifies. The air that has passed through the heat exchanger 25 is returned again to the hot air generator 24, where it is warmed and circulated.

  FIG. 2 shows only the part of the electrical configuration of the washing / drying machine 1 necessary for explaining the gist of the present invention, which will be described below. An inverter circuit 33 for supplying a drive current having a variable frequency and a variable voltage to each phase of the U, V, and W of the motor 14 connects the six IGBTs 34 to 39 to a three-phase bridge and fly to each of the IGBTs 34 to 39. The wheel diodes 34a to 39a are connected to each other, and the IGBTs 34 to 39 are individually turned on and off by respective phase PWM signals from a microcomputer 40 described later. In this case, the collectors of the IGBTs 34 to 36 on the upper arm side are connected to the DC power supply terminal 42 provided with the smoothing capacitor 41, and the emitters of the IGBTs 37 to 39 on the lower arm side are connected to the U, V, and W phases. The current detection shunt resistors 43u, 43v, and 43w are connected to the ground terminal. The resistance value of each shunt resistor 43u, 43v, 43w is set to 0.22Ω, for example. The DC power supply terminal 42 is an output terminal of a rectifier circuit configured to perform double voltage full wave rectification of a 100V AC power supply.

  The microcomputer 40 is constituted by a microcomputer having a rated operating voltage of 5 V, and this microcomputer is provided with a high-speed CPU in the form of a reduced instruction set computer (RISC) and a DSP that partially takes over the processing of the CPU. The power is supplied from a control power supply terminal VDD having an output voltage of 5V.

  Resistance voltage dividing circuits 44, 45, and 46 are connected between voltage output terminals of shunt resistors 43u, 43v, and 43w (corresponding terminals on the corresponding IGBT 37 to 39 side) and the 3.3V power supply, respectively. Each of the resistance voltage dividing circuits 44, 45, and 46 is composed of a series circuit of resistors R1 and R2, and the resistance value of each of the resistors R1 and R2 is set to 1 kΩ, for example. In addition, filter capacitors 47 are connected between the output terminals (common connection point of the resistors R1 and R2) of the resistor voltage dividing circuits 44, 45, and 46 and the ground terminal, respectively.

  FIG. 1 shows the internal configuration of the microcomputer 40 only in the part related to the gist of the present invention. The microcomputer 40 includes two A / D conversion circuits 50 and 51 using a 3.3 V power supply as a reference power supply AVDD, and these A / D conversion circuits 50 and 51 are provided via an input channel switch 52. The analog voltage signals thus obtained are individually converted to digital signals for signal processing. The A / D conversion circuits 50 and 51 are functions realized mainly by DSP software in the microcomputer 40.

  Three of the four input terminals in the input channel switch 52 are input terminals of the microcomputer 40 to which the divided voltages (voltages at the common connection point of the resistors R1 and R2) by the resistor voltage dividing circuits 44, 45, 46 are applied. Connected to VIU, VIV, and VIW. The microcomputer 40 is configured to detect each phase current value indicating the torque generated by the motor 14 based on the outputs of the A / D conversion circuits 50 and 51 and to perform vector control of the motor 14 based on the detected current value. Each phase PWM signal for turning on and off the IGBTs 34 to 39 is output according to the control. Note that the maximum rated current of the IGBTs 34 to 39 is, for example, 10A, and the microcomputer 40 forcibly turns off all the IGBTs 34 to 39 in order to prevent failure when the detected current value exceeds 10A. It also has.

  The microcomputer 40 reads the output voltage from the shunt resistors 43u, 43v, and 43w at the timing of the center point during the period when the lower arm IGBTs 37 to 39 are on. In this case, the output cycle of each phase PWM signal is set to 16 kHz, for example, which is sufficiently faster than the rotation speed of the motor 14, and the original waveform of the output voltage from the shunt resistors 43u, 43v, 43w is reproduced without any problem. it can.

  Further, the input terminals VIU, VIV, and VIW of the microcomputer 40 are respectively connected to the inverting input terminals of the comparators 54u, 54v, and 54w (overcurrent detection circuit) via the 100 kΩ resistive elements 53u, 53v, and 53w. Between each inverting input terminal and the ground, 5 pF capacitors 55u, 55v, and 55w are connected. The non-inverting input terminals of the comparators 54u, 54v, 54w are connected to the reference voltage input terminal VRI of the microcomputer 40. An A / D conversion reference voltage of 3.3V is applied to the input terminal VRI, and the resistors 56, 57 are connected. A potential divided by is applied. The output terminals of the comparators 54u, 54v, 54w are connected in common to the input terminal of the PWM emergency stop circuit 58, and the input terminal is pulled up to 5V by the resistor 90.

  If the voltage applied to the inverting input terminals of the comparators 54u, 54v, 54w is equal to or lower than the reference voltage of the input terminal VRI, the output terminals of the comparators 54u, 54v, 54w are maintained at a high level. From this state, if any phase current flowing through the inverter circuit 33 increases and the voltage at any inverting input terminal exceeds the reference voltage at the input terminal VRI, the PWM emergency stop circuit (abnormal processing circuit) 58 The input terminal changes to low level. When detecting the falling edge of the signal level change, the PWM emergency stop circuit 58 outputs an emergency stop signal pattern to the 6-phase PWM output circuit 60 via the abnormal output selection circuit (priority signal selection means) 59.

  The six-phase PWM output circuit 60 is a circuit that generates a PWM signal and outputs a gate drive signal to the gates of the IGBTs 34 to 39. The emergency stop signal pattern output by the PWM emergency stop circuit 58 is a gate signal pattern that turns off the IGBTs 34 to 39 and stops the switching operation by the inverter circuit 33. The 6-phase PWM output circuit 60 When a signal pattern is input, the pattern is output to the inverter circuit 33 as it is.

  A drive power supply voltage input terminal VIN of the microcomputer 40 is connected to the remaining input terminals of the input channel switch 52 via a resistor 61 having a resistance value of 100 kΩ. The input terminal VIN is supplied with a power supply voltage of 280 V supplied from the DC power supply terminal 42 divided by resistors 62 and 63, and a capacitor 64 of 1000 pF is connected to the ground outside the microcomputer 40. It is connected. A 5 pF capacitor 65 is connected between the input terminal of the input channel switch 52 and the ground. Accordingly, the A / D conversion circuit 50 or 51 also converts the drive power supply voltage supplied to the inverter circuit 33 via the input channel switch 52, and the microcomputer 40 performs the ripple control described above. And so on.

  The input terminal VIN is also connected to the inverting input terminal and the non-inverting input terminal of the comparators 66 and 67 (abnormal voltage detection circuit) via the resistor 61. The non-inverting input terminal and the inverting input of the comparators 66 and 67 are also connected. The terminals are connected to the reference voltage input terminals VRH and VRL of the microcomputer 40, respectively. These reference voltage input terminals VRH and VRL are given potentials obtained by dividing the 3.3 V A / D conversion reference voltage by resistors 91 and 92 and resistors 93 and 94, respectively.

  The output terminal of the comparator 66 is pulled up to 5 V via a resistor 68 and is connected to the input terminal of a motor emergency stop circuit (abnormality processing circuit) 69. If the voltage applied to the inverting input terminal of the comparator 66 is equal to or lower than the reference voltage of the input terminal VRH, the output terminal of the comparator 66 maintains a high level. From this state, when the drive power supply voltage rises and the voltage at the inverting input terminal of the comparator 66 exceeds the reference voltage at the input terminal VRH, the input terminal of the motor emergency stop circuit 69 changes to a low level. When the motor emergency stop circuit 69 detects the falling edge of the signal level change, the motor emergency stop circuit 69 outputs an emergency stop signal pattern to the 6-phase PWM output circuit 60 via the abnormal output selection circuit 59.

  In the emergency stop signal pattern, the upper-phase IGBTs 34 to 36 of the inverter circuit 33 are turned off and the lower-phase IGBTs 37 to 39 are turned on to form a short-circuit loop in the motor 14 via the inverter circuit 33 and short-circuit braking. When the signal pattern is input, the 6-phase PWM output circuit 60 outputs the pattern to the inverter circuit 33 as it is.

  On the other hand, the output terminal of the comparator 67 is connected to the input terminal of the PWM emergency stop circuit 58. When the drive power supply voltage decreases and the voltage at the non-inverting input terminal of the comparator 67 falls below the reference voltage at the input terminal VRL, the input terminal of the PWM emergency stop circuit 58 changes to a low level. Then, the PWM emergency stop circuit 58 outputs an emergency stop signal pattern to the 6-phase PWM output circuit 60 via the abnormal output selection circuit 59, as in the case of overcurrent detection.

  Next, the operation of this embodiment will be described. The voltage input terminal VIN is a terminal necessary for A / D conversion by the A / D conversion circuit 50 or 51 and for the CPU (not shown) of the microcomputer 40 to monitor the drive power supply voltage. The microcomputer 40 includes comparators 66 and 67 for determining abnormal voltage. When an abnormally high voltage or abnormally low voltage is detected by these, the emergency stop circuit 58 or 69, the selection circuit 59, and the PWM output circuit are detected. The abnormality handling process is performed by 60 circuit operations. That is, since these are directly processed by the hardware inside the microcomputer 40 without going through the CPU software processing, the abnormality handling processing can be performed quickly.

In addition, since the circuit elements configured inside the microcomputer 40 do not substantially increase the number of components, a configuration for dealing with an abnormal voltage can be realized with a minimum number of external circuit elements such as a voltage dividing resistor. .
Further, even when the operating power supply voltage of the microcomputer 40 is 5 V in order to ensure the dynamic range of the signal level of the peripheral I / O, the reference voltage of the A / D conversion circuits 50 and 51 is lower than the power supply voltage. Since it is set to 3 V, the resolution of A / D conversion does not decrease, and the detection accuracy of the motor torque is improved.

  As described above, according to the present embodiment, the A / D conversion circuits 50 and 51 are built in the microcomputer 40, and the DC power supply voltage supplied to the inverter circuit 33 via the input channel switch 52 is input to these input terminals. When the voltage signal VIN for monitoring the signal is given and it is determined that the voltage signal is out of the normal range, the abnormal voltage detection signal is directly transmitted to the emergency stop circuit 58 or 69 without passing through the CPU which is a part of the abnormal voltage detection signal. Output it. Therefore, it is possible to reliably detect the abnormal voltage at a low cost and to quickly cope with the occurrence of the abnormal voltage. And since generation | occurrence | production of an abnormally high voltage can be prevented, a low voltage | pressure-resistant circuit component can be used, and size reduction and cost reduction can be achieved.

  Further, the comparator 66 and 67 can compare the voltage signal VIN with the threshold voltages VRH and VRL, detect an abnormal voltage by simple analog signal processing, and simply add a simple circuit, thereby increasing the chip size of the microcomputer 40. Can also be suppressed. Then, by connecting the resistor 61 and the capacitor 64 to the input terminals of the comparators 66 and 67 to form a filter circuit, when the voltage signal VIN is out of the normal range for a predetermined time or longer, the comparator 66, 67 outputs an abnormal voltage detection signal, so that erroneous detection due to a temporary voltage change when noise is applied can be prevented.

  Further, when the comparator 66 outputs an abnormal voltage detection signal on the high voltage side, the motor emergency stop circuit 58 turns on all the lower arm side IGBTs 37 to 39 constituting the inverter circuit 33 and also turns on the upper arm side IGBTs 36 to 38. Are all turned off, so that the short-circuit braking is applied to the motor 14 to consume abnormally high voltage energy, and the voltage can be lowered. Further, when the comparator 67 outputs an abnormal voltage detection signal on the low voltage side, the PWM emergency stop circuit 69 turns off all the IGBTs 36 to 39 constituting the inverter circuit 33 and stops the driving of the motor 14. Therefore, when the power supply voltage suddenly drops due to a power failure or the like, the operation of the inverter circuit 33 becomes unstable, and it is possible to avoid a circuit component from being damaged due to an abnormal large current flowing.

  In addition, the microcomputer 40 includes comparators 54u, 54v, and 54w that output an overcurrent detection signal when detecting an overcurrent state of the current flowing through the inverter circuit 33. The six-phase PWM output circuit 60 includes an overcurrent detection signal. The abnormal output selection circuit 59 is configured to perform the corresponding abnormal processing even when a signal is output, and the abnormal output selection circuit 59 gives priority to any signal when the abnormal voltage detection signal from the comparator 67 is also output. Set whether to output. For example, by giving priority to the short-circuit braking operation when the motor 14 rotates at high speed and prioritizing the OFF operation of the inverter circuit 33 when rotating at a low speed, the circuit components can be reliably protected.

  For example, when an amplifier using an operational amplifier is provided at the input stage of the A / D conversion circuits 50 and 51, a phenomenon occurs in which the rising and falling waveforms of the input voltage Vin (amplified output voltage by the amplifier) become dull due to the slew rate of the operational amplifier. However, in a region where the motor current is small, the input voltage Vin may be lower than the level that should be detected. Since the detected current includes an error due to an offset voltage temperature drift of the amplifier, a deviation occurs between the actual motor current and the motor current detected based on the input voltage Vin. The control operation of the microcomputer 40 performed on the basis may be affected. In this embodiment, since no amplifier is used in the input stage of the A / D conversion circuits 50 and 51, it is possible to prevent an increase in error due to the presence of the amplifier, thereby contributing to an improvement in motor torque detection accuracy. In addition, the configuration can be simplified at the same time.

(Second embodiment)
FIG. 4 shows a second embodiment of the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Hereinafter, different parts will be described. In the microcomputer 71 of the second embodiment, the reference voltage of the A / D conversion circuits 50A and 51A is set to 5 V which is the same as the operation power supply voltage of the microcomputer 71. In addition, an amplification amplifier 72 having an amplification factor of, for example, 3 is inserted between the input side of the input channel switch 59 and the input terminals VIU, VIV, and VIW. In this case, the shunt resistors arranged in the inverter circuit are replaced with shunt resistors 43u ′, 43v ′, and 43w ′ having a resistance value of 0.1Ω. Other configurations are the same as those in the first embodiment.
According to the second embodiment configured as described above, by disposing the amplification amplifier 72, it is possible to compensate for a decrease in resolution when the reference voltage for A / D conversion is set to 5V. In addition, since the power supply voltage used by the microcomputer 71 can be unified to 5V, the configuration of the power supply circuit is simplified.

(Third embodiment)
FIG. 5 shows a third embodiment of the present invention, and only parts different from the first embodiment will be described. The microcomputer 73 of the third embodiment has an operating power supply voltage set to 3.3 V, which is the same as the reference voltage for A / D conversion, and other configurations are the same as those of the first embodiment. According to the third embodiment configured as described above, since the power supply voltage used by the microcomputer 73 can be unified to 3.3 V, the configuration of the power supply circuit is simplified.

(Fourth embodiment)
6 and 7 show a fourth embodiment of the present invention, which corresponds to a part of FIG. The microcomputer 74 of the fourth embodiment does not use a comparator which is an analog circuit as in the first to third embodiments, but uses a magnitude comparator (digital comparator) 75 to similarly perform a power supply voltage monitoring operation. It is configured as follows.

  That is, the comparator 75 is arranged on the output side of the A / D conversion circuit 50 (A / D conversion circuit 51 is not shown), and one of the input terminals of the comparator 75 has an A / D conversion. Data A / D converted by the circuit 50 is given. When a CPU (not shown) of the microcomputer 74 reads the conversion data of the A / D conversion circuit 50, the data output on the data bus is read via the read buffer 76. The other input terminal of the comparator 75 is supplied with threshold data for voltage monitoring from the monitoring register 77. The output terminal of the comparator 75 is connected to the input terminal of the determination unit (signal output circuit) 78.

  The determination unit 78 includes an input determination unit 79 and a frequency determination unit (comparison result storage circuit) 80. The input determination unit 79 outputs the output result of the comparator 75 as a monitoring input designation unit 81 and a comparison unit (determination control means). ) Is output to the frequency determination unit 80 at the enable timing given via 82. The number determination unit 80 counts the number of times that the comparison result given through the input determination unit 79 is “established”, and when the count value matches the number of times specified in the number specification unit (determination control means) 83, A determination signal is output to the motor emergency stop circuit 69 and a monitoring interrupt is generated for the CPU of the microcomputer 74.

  An A / D conversion control unit (input signal selection means, determination control means) 84 performs input selection of a signal input terminal in the input channel switch (input signal selection means) 52 and starts conversion to the A / D conversion circuit 50. A signal is given, and a signal indicating that conversion processing is in progress is given from the A / D conversion circuit 50. The input selection signal output from the A / D conversion control unit 84 is also given to the comparison unit 82. Note that data settings for various registers and the like are performed by the CPU of the microcomputer 74. The above constitutes the abnormal voltage detection circuit 85.

  Next, the operation of the fourth embodiment will be described with reference to FIG. FIG. 7 is a timing chart of the configuration shown in FIG. The A / D conversion control unit 84 switches the selection of the signal input terminal in the input channel switching unit 52 as shown in FIG. Then, according to the input selection, the analog voltage applied to the input terminal of the A / D conversion circuit 50 is switched as shown in FIG. Further, the A / D conversion control unit 84 gives a conversion start signal to the A / D conversion circuit 50 as shown in FIG. 7C, and monitors the signal being converted (see FIG. 7D).

  As shown in FIG. 7C, in the monitoring input designating unit 81, “analog input 4” in the input channel switch 52 is designated as a monitoring target, and in the number designating unit 83, a determination signal is sent. The number of comparison establishment until output is set to “3”. The monitoring register 77 is supplied with threshold data D42 for voltage monitoring. As described above, the input selection signal output from the A / D conversion control unit 84 is given to the comparison unit 82, but the input selection signal is given a slight delay inside the comparison unit 82. It has become.

  FIG. 7E shows data obtained by A / D converting the analog input voltage shown in FIG. 7B by the A / D conversion circuit 50. Here, it is assumed that the conversion result data corresponding to “analog input 4” is D40 to D44, but changes so that D40 <D41 <D42 <D43 <D44. Therefore, in the case of the conversion data D40 and D41, the output signal of the comparator 75 does not change, but in the case of the conversion data D42, the output signal of the comparator 75 changes from the low level to the high level by matching with the threshold data D42 (FIG. 7 (i)). Then, the number determination unit 80 catches the level change of the output signal through the input determination unit 79 and increments the counter of comparison establishment number (see FIG. 7J).

When the counter value in the number determination unit 80 matches the set value “3” in the number specification unit 83, the determination unit 78 outputs a determination signal to the motor emergency stop circuit 69 and monitors the CPU of the microcomputer 74. An interrupt is generated (see FIGS. 7 (k) and (l)).
The counter value of the number determination unit 80 is reset if the output level of the comparator 75 is low when the output level of the comparison unit 82 is active (high). Therefore, since the counter value is reset when a state where the A / D conversion result of the power supply voltage is less than the threshold data D42 occurs, the case where the state where the A / D conversion result is equal to or higher than the threshold data D42 is only once or only twice. If it continues, the judgment signal is not output because it is reset thereafter. The counter value is also reset when the CPU invalidates the function of the abnormal voltage detection circuit 85 by operating a control register (not shown).

  As described above, according to the fourth embodiment, the abnormal voltage detection circuit 85 compares the output data of the A / D conversion circuit 50 with the threshold voltage data of the monitoring register 77 by the comparator 75, and the comparison result by the comparator 75 is obtained. When the number-of-times determining unit 80 indicates that it has been out of the normal range three times in succession, the determining unit 78 outputs an abnormal voltage detection signal to the motor emergency stop circuit 69.

  Therefore, unlike the configurations of the first to third embodiments, the abnormal voltage detection circuit 85 can be configured entirely with a digital circuit. When the microcomputer 74 is configured as a semiconductor integrated circuit on a single chip, the same process is used. It is possible to easily form an integral configuration. Then, the A / D conversion control unit 84 selects the voltage signal to be converted by the A / D conversion circuit 50 by the input channel switch 52, and the comparator 75 compares the A / D conversion result of the selected voltage signal. The result is used for determination for detecting abnormal voltage. Therefore, the A / D conversion circuit 50 can be used for purposes other than the purpose of detecting an abnormal voltage.

(5th Example)
8 and 9 show a fifth embodiment of the present invention, and only the parts different from the fourth embodiment will be described. As shown in FIG. 8, the microcomputer 86 of the fifth embodiment includes registers (conversion result registers) 87 (1) to 87 (4) for storing conversion result data on the output side of the A / D conversion circuit 50. Is arranged. The A / D conversion control unit 88 that replaces the A / D conversion control unit 84 is also configured to perform update control of the result registers 87 (1) to 87 (4). The above constitutes the abnormal voltage detection circuit 89.

  Next, the operation of the fifth embodiment will be described with reference to FIG. In the timing chart shown in FIG. 9, (a) to (l) are attached to the same signals as those corresponding to FIG. 7 of the fourth embodiment, and A / D is provided between (e) and (f). The update control for the result registers 87 (1) to 87 (4) by the conversion control unit 89 and the update state of the result registers 87 (1) to 87 (4) are shown.

  When the input analog voltage changes in the same manner as in the fourth embodiment, the A / D conversion control unit 88 corresponds to the selected input terminal: analog input 1 to 4 and the conversion result by the A / D conversion circuit 50. A control signal (latch signal) is output so as to switch between the registers 87 (1) to 87 (4) for storing. Therefore, in the result register 87 (4), conversion result data corresponding to the analog input 4 is stored, and the data value sequentially changes to D40, D41, D42, D43, and D44. Then, the comparison control itself for detecting the abnormal high voltage by the comparator 50 is executed in the same manner as in the fourth embodiment.

  As described above, according to the fifth embodiment, since four result registers 87 are provided for storing the output data of the A / D conversion circuit 50, the conversion result is obtained at every timing when the A / D conversion is performed. There is no need to read out, and the processing of the CPU constituting the microcomputer 86 can be reduced. Further, the latest value of the conversion result for monitoring the power supply voltage can be held in the register 87 (4).

The present invention is not limited to the above-described embodiments, and can be modified or expanded as described below, for example.
The microcomputer may include only one A / D conversion circuit or three or more A / D conversion circuits.
The PWM emergency stop circuit 58 and the abnormal output selection circuit 59 may be provided as necessary.
The fourth and fifth embodiments may be configured in the same manner for those detecting an abnormally low voltage.
In the fourth and fifth embodiments, a configuration for generating an interrupt to the CPU may be provided as necessary.
The number of comparison establishments that output the determination signal may be “2” or “4” or more.
The motor-applied home appliance is not limited to a washing / drying machine, and may be a drum-type or vertical washing machine, a drying machine, an air conditioner, or the like.

The 1st Example of this invention and the figure which shows only the part which concerns on the summary which concerns on the summary of this invention about the structure inside the microcomputer which controls a washing dryer. The figure which shows only the part which is necessary for explanation among the electric constitution of the washing dryer The figure which shows the whole structure of a drum type washing-drying machine FIG. 1 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. FIG. 1 is a partial equivalent diagram of FIG. 1 showing a fourth embodiment of the present invention. Timing chart FIG. 6 equivalent view showing the fifth embodiment of the present invention. 7 equivalent diagram

Explanation of symbols

  In the drawings, 1 is a washing / drying machine (motor-applied home appliance), 14 is a DC brushless motor, 33 is an inverter circuit, 40 is a microcomputer, 50 and 51 are A / D conversion circuits, and 58 is a PWM emergency stop circuit (abnormal processing) Circuit) 59, an abnormal output selection circuit (priority signal selection means), 66, 67 a comparator (abnormal voltage detection circuit), 69 a motor emergency stop circuit (abnormal processing circuit), 71, 73, 74 a microcomputer, 75 Is a magnitude comparator, 78 is a determination unit (signal output circuit), 80 is a number determination unit (comparison result storage circuit), 82 is a comparison unit (determination control unit), 83 is a number specification unit (determination control unit), and 84 is A. / D conversion control unit (input signal selection means, determination control means), 85 an abnormal voltage detection circuit, 86 a microcomputer, 87 a conversion result register, 8 A / D conversion control section (input signal selecting means, the judgment control unit), 89 denotes an abnormal voltage detection circuit.

Claims (9)

In an inverter of a motor applied home appliance configured to include an inverter circuit that drives a motor for home appliances and a microcomputer that controls the inverter circuit,
The microcomputer is
An A / D conversion circuit is incorporated, and a voltage signal for monitoring a DC power supply voltage supplied to the inverter circuit is given to an input terminal of the A / D conversion circuit,
If it is determined that the voltage signal is out of the normal range, an abnormal voltage detection signal is output directly to an abnormal processing circuit for coping with the occurrence of the abnormal voltage without using a CPU that is a part of the abnormal voltage detection signal. An inverter for home appliances with motors, characterized by comprising a voltage detection circuit.   The inverter of the motor applied home appliance according to claim 1, wherein the abnormal voltage detection circuit includes a comparator that compares the voltage signal with a threshold voltage.   The abnormal voltage detection circuit is configured such that the comparator outputs the abnormal voltage detection signal when the voltage signal is outside the normal range for a predetermined time or longer. The inverter of the motor application household appliances of Claim 2. The abnormal voltage detection circuit includes:
A magnitude comparator (digital comparator) for comparing output data of the A / D converter circuit with threshold voltage data;
A comparison result storage circuit for storing a previous comparison result by the comparator one or more times;
2. The signal output circuit according to claim 1, further comprising: a signal output circuit that outputs the abnormal voltage detection signal when a comparison result by the comparator indicates that the comparison result is out of the normal range for a plurality of consecutive times. Inverter for motor applied home appliances. Input signal selection means for selecting a voltage signal to be converted by the A / D conversion circuit from a plurality of analog signal input terminals;
5. A determination control means for using the result of comparison of the A / D conversion result of the voltage signal selected by the input signal selection means by the comparator for determination for detecting abnormal voltage. Inverter for motor applied home appliances described.   The inverter of the motor applied home appliance according to claim 4 or 5, comprising a plurality of conversion result registers for storing output data of the A / D conversion circuit.   When the abnormal voltage detection circuit outputs an abnormal voltage detection signal on the high voltage side, the abnormality processing circuit of the microcomputer turns on all the switching elements on the lower arm side constituting the inverter circuit, and All the switching elements are turned OFF, The inverter of the motor application household appliances in any one of Claims 1 thru | or 6 characterized by the above-mentioned.   The abnormality processing circuit of the microcomputer turns off all the switching elements constituting the inverter circuit when the abnormal voltage detection circuit outputs an abnormal voltage detection signal on a low voltage side. The inverter of the motor application household appliances in any one of 7. The microcomputer is
When an overcurrent state of current flowing through the inverter circuit is detected, an overcurrent detection circuit that outputs an overcurrent detection signal is provided,
The abnormality processing circuit is configured to perform abnormality processing corresponding to the case where the overcurrent detection signal is output,
Priority signal selection means for setting which signal is preferentially output to the abnormality processing circuit when the overcurrent detection signal and the abnormal voltage detection signal by the abnormal voltage detection circuit are simultaneously output. The inverter of the motor applied household appliances in any one of Claims 1 thru | or 8 characterized by the above-mentioned.

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