JP4816359B2 - Motor drive device - Google Patents

Description

  The present invention relates to an overheat protection means for a motor driving device built in a small brushless motor used for home appliance air conditioning equipment and the like.

  Conventionally, there is an overheat protection of a motor drive device built in a brushless motor as shown in the circuit diagram of FIG.

  FIG. 5 shows an overheat protection means 307 whose output terminal is connected to the PWMDUTY command signal input terminal 316 of the one-chip IC 306 of the brushless motor driving means. When the voltage exceeds a predetermined value, the input voltage of the PWM DUTY command signal input terminal 316 is reduced or is set to 0 to limit or turn off the ON period of the switch element 305, thereby suppressing overheating of the switch element, There is high reliability that does not cause destruction of the driving device even in the case of overload.

  The overheat protection means 307 is simply configured by a thermistor, a resistor, and a transistor that are temperature sensitive elements (see, for example, Patent Document 1).

However, in such a configuration, when the periphery of the thermistor becomes a high temperature environment, the resistance value of the thermistor decreases, the current increases in the thermistor, and the self-heating of the thermistor itself increases. That is, since the detected temperature = the ambient temperature + the thermistor heat generation temperature, there is a problem that the temperature detection with high accuracy cannot be performed because the thermistor has a large self-heat generation.
JP 2002-354870 A

  The problem to be solved by the present invention is to realize a motor drive device having overheat protection means that can detect the temperature accurately while minimizing the self-heating of a temperature sensitive element such as a thermistor.

  In order to solve the above-mentioned problem, the present invention connects in series the temperature sensing element, the first resistor, and the second resistor between the constant voltage source and GND, and the voltage of the first resistor and the second resistor is It was provided as a temperature detection result.

  Even if the resistance value of the temperature sensing element is remarkably lowered in a high temperature environment, the first and second resistances are set to a predetermined high resistance to suppress a loss due to an increase in the current flowing through the temperature sensing element. The self-heating is suppressed, and the temperature around the temperature sensing element can be accurately detected.

According to the first aspect of the present invention, there is provided a semiconductor integrated circuit having a control input terminal that varies the power supplied to the motor winding by an analog voltage signal from the outside, and a temperature sensitivity that reduces the resistance value when the temperature rises. In the motor drive device having the overheat protection means using the element, the temperature sensing element of the overheat protection means has one end connected to the positive output of the constant voltage source and the other end connected to the first resistor, The other end of the resistor is connected to one end of the second resistor and to the input terminal of the first resistor built-in transistor, and the output terminal of the first resistor built-in transistor is the control input terminal of the semiconductor integrated circuit And the other of the second resistor and the emitter of the first resistor-embedded transistor are connected to the negative output of the constant voltage source, so that there is no first resistor even in a high temperature environment. The other end of the second resistor Compared to the case of direct connection, the motor drive device is characterized by reducing internal loss due to the current flowing in the temperature sensing element, and provides high-precision overheat protection means that minimizes the self-heating of the temperature sensing element. It has the effect of being able to.

  According to a second aspect of the present invention, there is provided a semiconductor integrated circuit having a protective input terminal that cuts off the power supply to the motor winding when a predetermined voltage is reached, and reduces the resistance value when the temperature rises. In the motor drive device having the overheat protection means using the temperature sensing element, the temperature sensing element of the overheat protection means has one end connected to the positive output of the constant voltage source and the other end connected to the first resistor, The other end of the first resistor is connected to one end of the second resistor and is connected to the protective input terminal of the semiconductor integrated circuit, and the other end of the second resistor is connected to the negative side output. Below, the motor drive is characterized in that the internal loss due to the current flowing through the temperature sensing element is reduced compared to the case where there is no first resistance and the other end of the temperature sensing element is directly connected to the second resistance. The accuracy of the device, which minimizes the self-heating of the temperature sensing element It has the effect of being able to provide good thermal protection means.

  FIG. 1A shows a motor drive device 1 according to claim 1 of the present invention, and FIG. 1B shows a detailed view of an overheat protection means 9 of the drive device 1.

  In FIG. 1A, the main power supply 2 is connected to the Vdc terminal of 13 semiconductor integrated circuits (IC) via the main power supply input terminal 5. The control power supply 3 is connected to the Vcc terminal of the IC 13 via the control power input terminal 7 and input to the regulator 10. The regulator 10 supplies the constant voltage VB to the overheat protection means 9. The analog signal source 4 is connected to the Vsp terminal of the IC 13 via the control input terminals 7 and R 3 and is input to the PWM signal generator 11. When the voltage value of the analog signal source 4 increases, the switch means 12 increases the power supply to the motor windings L1, L2, and L3 by the action of the PWM signal generator 11, and conversely, the analog signal source 4 When the voltage value decreases, the switch means 12 reduces the power supply to the motor windings L1, L2, and L3 by the action of the PWM signal generator 11.

  In the overheat protection means 9 in FIG. 1B, one thermistor (NTC), which is a temperature sensitive element, is connected to the constant voltage VB, and the other is connected to one of the first resistors (R1). The other of R1 is connected to one of the second resistors (R2) and is connected to the input of the transistor with built-in resistor Q1, and the other of R2 is connected to Gnd. The collector of Q1 is connected to the Vsp terminal of the IC 13, and the emitter is connected to Gnd.

FIGS. 1C and 1D show Q1 input voltage Vin (V), NTC self-loss Pd (mW), and loss Pd at Ta = 25 ° C. (25 ° C.) with respect to changes in environmental temperature Ta (° C.) of NTC. It is a table | surface which shows the characteristic of ratio Pd / Pd (25 degreeC). FIG. 1C is a characteristic table in which R1 = 0 kΩ and R2 = 0.56 kΩ are designed so that Vin = about 0.9 V at which Ta1 is conducted at Ta = 95 ° C. in order to show the characteristics of the conventional example. . FIG. 1 (d) shows self-loss at Ta = 95 ° C. so that Vin = approximately 0.9V when Ta = 95 ° C. and Q1 conducts in order to show the characteristics of the present invention. 4 is a characteristic table designed as R1 = 9.1 kΩ and R2 = 2.7 kΩ as an example in which is reduced.

  Focusing on Pd / Pd (25 ° C.) with Ta = 95 ° C., the ratio in FIG. 1 (c) is 17.118 times as compared with the 25 ° C. ratio, whereas FIG. 1 (d) is 2.162 times. , The loss increase of the NTC itself is suppressed to a minimum increase compared to the case of R1 = 0 kΩ.

  2A shows the motor drive device 21 according to claim 2 of the present invention, and FIG. 2B shows a detailed view of the overheat protection means 23 of the drive device 21. FIG.

  In FIG. 2A, the main power supply 2 is connected to the Vdc terminal of 22 semiconductor integrated circuits (ICs) through the main power supply input terminal 5. The control power source 3 is connected to the Vcc terminal of the IC 22 via the control power source input terminal 7 and supplied to the overheat protection means 23. The output of the overheat protection means 23 is output from the TSD circuit of the IC 22 via the TSD terminal. Is input. The analog signal source 4 is connected to the Vsp terminal of the IC 13 via the control input terminals 7 and R 3 and is input to the PWM signal generator 11. When the voltage value of the analog signal source 4 increases, the switch means 12 increases the power supply to the motor windings L1, L2, and L3 by the action of the PWM signal generator 11, and conversely, the analog signal source 4 As in the first embodiment, when the voltage value is reduced, the switch means 12 reduces the power supply to the motor windings L1, L2, and L3 by the action of the PWM signal generator 11.

  In the overheat protection means 23 of FIG. 2B, one thermistor (NTC), which is a temperature sensitive element, is connected to the control power supply Vcc, and the other is connected to one of the first resistors (R1). The other of the R1 is connected to one of the second resistors (R2), forms the output of the overheat protection means 23, is connected to the TSD terminal of the IC 22, and the other of R2 is connected to Gnd.

  2C and 2D show the IC 22 TSD terminal input voltage Vtsd (V), NTC self-loss Pd (mW), and Ta = 25 ° C. loss Pd (25) with respect to changes in environmental temperature Ta (° C.) of NTC. It is a table | surface which shows the characteristic of ratio Pd / Pd (25 degreeC) with (degreeC). In FIG. 2C, R1 = 0 kΩ is set to show the characteristics of the conventional example, and the TSD circuit of the IC 22 becomes Vtsd = about 2.9 V, which is the motor winding power supply stop level of the switch means 12 at Ta = 95 ° C. It is a characteristic table designed so that R2 = 0.91 kΩ. FIG. 2D shows the characteristics of the present invention, as in FIG. 2C, when Ta = 95 ° C. and the TSD circuit of the IC 22 is the motor winding power supply stop level of the switch means 12 Vtsd = about 2.9V. FIG. 5 is a characteristic table designed as R1 = 9.1 kΩ and R2 = 4.3 kΩ as an example in which the self-loss at Ta = 95 ° C. is reduced.

  Focusing on Pd / Pd (25 ° C.) at Ta = 95 ° C., in FIG. 2 (c), it is 15.161 times the ratio of 25 ° C., whereas in FIG. 2 (d) it is 1.849 times. , The loss increase of the NTC itself is suppressed to a minimum increase compared to the case of R1 = 0 kΩ.

  The IC 13 in each of the above embodiments is a monolithic switch unit and various circuits for controlling the switch unit integrated on a single silicon chip. In addition, a plurality of powers can be used instead of the IC. Even if the switch element or a configuration in which a plurality of power switch elements and a driver IC for driving the power switch element are replaced with a power module integrated with each other, the same effect can be obtained by using the same overheat protection means as in the first or second embodiment. It is done.

  The present invention may contribute not only to overheating protection of a motor drive device but also to improvement of reliability of a product incorporating a P plate having a heat generating component.

(A) is a figure which shows the form of the motor drive device of Claim 1 of this invention, (b) is a figure which shows the detail of the overheat protection means in the said drive device, (c) is a figure of the overheat protection means of this invention. The figure which shows a temperature characteristic table, (d) is a figure which shows the temperature characteristic table of the same overheat protection means (A) is a figure which shows the form of the motor drive device of Claim 2 of this invention, (b) is a figure which shows the detail of the overheat protection means in the said drive device, (c) is a figure of the overheat protection means of this invention. The figure which shows a temperature characteristic table, (d) is a figure which shows the temperature characteristic table of the same overheat protection means The figure which shows the form of the conventional motor drive device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor drive device of Claim 1 of this invention 2 Main power supply 3 Control power supply 4 Analog voltage signal source 5 Main power supply input terminal 6 Control power supply input terminal 7 Control input terminal 8 GND terminal 9 Overheat protection means 10 of Claim 1 Regulator 11 PWM signal generator 12 Switch means 13 The semiconductor integrated circuit (IC) according to claim 1
21. A motor driving device according to claim 2 of the present invention. 22. A semiconductor integrated circuit (IC) according to claim 2.
23. Overheat protection means according to claim 2 24 TSD circuit

Claims (2)

Motor drive device having a semiconductor integrated circuit having a control input terminal that varies the power supplied to the motor winding by an analog voltage signal from the outside, and an overheat protection means using a temperature sensitive element that reduces the resistance value when the temperature rises The temperature sensing element of the overheat protection means has one end connected to the positive output of the constant voltage source and the other end connected to the first resistor, and the other end of the first resistor is one end of the second resistor. is connected is connected to an input terminal of a resistor internal transistor, an output terminal of the resistor built transistor connected to said control input terminal of the semiconductor integrated circuit, the second resistor of the other, and the first resistor A motor driving device characterized in that an emitter of a built-in transistor is connected to a negative output of a constant voltage source. Motor having overheat protection means using a semiconductor integrated circuit having a protection input terminal that cuts off power supply to the motor winding when a predetermined voltage is reached, and a temperature sensing element that decreases the resistance value when the temperature rises In the driving device, the temperature sensing element of the overheat protection means has one end connected to the positive output of the constant voltage source, the other end connected to the first resistor, and the other end of the first resistor connected to the second resistor. A motor driving device characterized in that it is connected to one end of a resistor and connected to a protection input terminal of the semiconductor integrated circuit, and the other end of the second resistor is connected to a negative output.

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