JP2015145863A - resolver control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resolver control device configured to reduce power consumption of a resolver when an inverter is shut down.SOLUTION: A resolver control device includes: an input section which receives a rotation angle detection signal output from a resolver which detects a rotation angle of a motor to be driven by an inverter; a control section which outputs a shutoff signal for shutting off a drive output which drives the inverter; an excitation signal switching section which switches an amplitude of an excitation signal to be applied to the resolver when the control section outputs the shutoff signal; and an amplification factor switching section which switches an amplification factor of the rotation angle detection signal when the control section outputs the shutoff signal.

Description

    The present invention relates to a resolver control device.

  2. Description of the Related Art Conventionally, there is a rotation angle detection device that reduces the power consumption of a circuit by reducing the amplitude of an excitation signal when the rotation angle is not required to be accurate and the detected rotation angle may be coarse (see, for example, Patent Document 1) reference).

  In addition, there is a resolver control device that reduces power consumption by making the amplitude of the excitation voltage of the excitation circuit smaller than usual during a power failure (see, for example, Patent Document 2).

JP 2005-037254 A Japanese Patent Laid-Open No. 08-014942

  However, in the conventional technique, the power consumption of the resolver cannot be reduced when the inverter that drives the motor that is the load is shut down.

  Accordingly, an object of the present invention is to provide a resolver control device that reduces the power consumption of a resolver when an inverter is shut down.

  The resolver control device according to the present invention outputs an input unit to which a rotation angle detection signal output from a resolver that detects a rotation angle of a motor driven by an inverter is input, and a cutoff signal that blocks a drive output that drives the inverter. A control unit that switches the amplitude of the excitation signal applied to the resolver when the control unit outputs the cutoff signal, and the rotation angle detection when the control unit outputs the cutoff signal. An amplification factor switching unit that switches the amplification factor of the signal.

  According to the embodiment of the present invention, it is possible to provide a resolver control device that reduces the power consumption of the resolver when the inverter is shut down.

The block diagram which shows the electric circuit of the resolver control apparatus in 1st Embodiment The block diagram which shows the electric circuit of the resolver control apparatus in 2nd Embodiment

Hereinafter, an embodiment which is an example of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a first embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram illustrating an electric circuit of the resolver control device according to the first embodiment.

  In FIG. 1, a resolver control device 1 drives an IBGT (Insulated Gate Bipolar Transistor) 2 as an inverter, and drives and rotates a motor (not shown). A resolver 3 for detecting the rotation angle of the motor is attached to the motor. The resolver control device 1 can be realized by an ECU (Electronic Control Unit) that electronically controls the resolver, for example.

  The resolver 3 includes an excitation coil 31, detection coils 32 and 33, and a rotor 34 connected to the rotor of the motor. The detection coil 32 and the detection coil 33 output a rotation angle detection signal whose voltage changes according to the rotation angle of the rotor 34. The amplitude of the rotation angle detection signal is proportional to the amplitude of the excitation signal applied to the excitation coil 31. If the rotation angle detection signal output from the detection coil 32 is a sine wave, the rotation angle detection signal output from the detection coil 33 is a cosine wave orthogonal to the sin wave. The resolver control device 1 includes an input unit (sin, sing) and an input unit (cos, cosg) as input units to which a rotation angle detection signal is input.

  The resolver control device 1 includes a microcomputer 11 as a control unit. The microcomputer 11 includes a shutdown output unit (SDWN), a PWM (Pulse Width Modulation) output unit (PWM), a resolver excitation signal output unit (RSO), and a rotation angle detection signal input unit (sin, cos).

  The PWM output unit of the microcomputer 11 outputs a PWM signal for driving the IGBT 2. The PWM signal is a signal for controlling the output of the IGBT 2 by changing the duty ratio of the pulse wave. The PWM output unit outputs a PWM signal to the gate of M2, which is an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), through a resistor r2. M2 is switched by the input PWM signal, and drives the photocoupler 12 with the power supply voltage VB1 through the resistor r21. The photocoupler 12 converts the PWM signal output from the M2 into a PWM signal based on the power supply voltage VB2 insulated from the power supply voltage VB1, and inputs the PWM signal to the PWM input unit of the pre-driver IC13. The pre-driver IC 13 outputs a drive output that drives the gate of the IGBT 2 via the resistor r3 based on the input PWM signal. In FIG. 1, only one IGBT 2 is illustrated for simplicity of explanation. For example, an IGBT that forms an upper arm and an IGBT that forms a lower arm are set as one set for one phase. Three sets of IGBTs including three phases of a U phase, a V phase, and a W phase may be used.

  The shutdown output unit of the microcomputer 11 outputs a cutoff signal that cuts off the output of the IGBT 2. The interruption of the output of the IGBT 2 is performed for the purpose of power saving when the motor has a low load, for example, when the vehicle is stopped. The cutoff signal is input from the shutdown output unit to M1, which is a P-channel MOSFET, via a resistor r1. When a cut-off signal is input to the gate of M1, the power supply of the power supply voltage VB1 is cut off, the photocoupler 12 is stopped, and the drive of the pre-driver IC 13 is stopped, whereby the drive output to the IGBT 2 is stopped and the IGBT 2 Output is cut off.

  The resolver excitation signal output unit of the microcomputer 11 outputs an excitation signal applied to the excitation coil 31 of the resolver 3. The resolver control device 1 includes an operational amplifier OP1 and resistors r4, r5, and r6, and amplifies the excitation signal output from the resolver excitation signal output unit. The resistor r6 is connected in parallel to a circuit in which a switch sw1 and a resistor r62 are connected in series to the resistor r61. The transistors Tr1 and Tr2 constitute an output stage to the exciting coil 31 by the power supply voltage VB3 with respect to the output of the operational amplifier OP1 inputted to the base via the resistors r7 and r8. The capacitor c1 functions as an AC coupling capacitor and cuts the DC component of the excitation signal.

  The excitation signal applied to the excitation coil 31 is output from the resolver excitation signal output unit with an amplitude having a sufficient S / N ratio in order to reduce the influence of switching noise and the like of the IGBT 2. However, when the cutoff signal is output from the microcomputer 11 and the output of the IGBT is shut off, the switching noise due to the IGBT disappears and the noise level is lowered. Therefore, even if the amplitude of the excitation signal is reduced, the SN ratio is increased. be able to. By reducing the amplitude of the excitation signal applied to the excitation coil 31, power consumption by the excitation coil 31 can be reduced.

When the voltage output from the excitation signal output unit is Vrso, the voltage V0 input to the capacitor c1 is expressed by the following expression 1.
V0 = (VB4-Vrso) r6 / r4 + VB4 (r6 / r5 + 1) (Formula 1)
Since VB4 which is a DC component of V0 input to the capacitor c1 is cut, the excitation signal voltage Vref applied to the excitation coil 31 is expressed by the following equation (2).
Vref = −Vrso · r6 / r4 (Expression 2)
From Equation 2, the excitation signal amplification factor is proportional to the resistance value of the resistor r6.

  The resistance value of the resistor r6 is parallel to r61 and r62 because the switch sw1 is closed when a cutoff signal is input. Therefore, the resistance value of the resistor r6 is r6 = r61 · r62 / (r61 + r62). On the other hand, since the switch sw1 is in an open state when no cutoff signal is input, the resistance value of the resistor r6 is r6 = r61. Since the amplification factor of the excitation signal is proportional to the resistance value of r6, the amplification factor can be switched by opening / closing the switch sw1 and the amplitude of the excitation signal can be switched by selecting the resistance values of the resistors r61 and r62. For example, when r61 = r62, the amplitude of the excitation signal when the switch sw1 is closed is reduced to ½ compared to when the switch sw1 is open. sw1 operates as an excitation signal switching unit, and enables the amplitude of the excitation signal to be switched by opening and closing sw1.

  The resolver control device 1 includes amplification units 14 and 15. The rotation angle detection signal output from the detection coil 32 is input to the amplification unit 14 from the input unit (sin, sing). The rotation angle detection signal output from the detection coil 33 is input to the amplification unit 15 from the input unit (cos, cosg). Since the amplification units 14 and 15 are the same circuit A, the description of the amplification unit 15 is omitted in FIG.

The amplifying unit 14 includes an operational amplifier OP2 and resistors r11, r12, r13, and r14, amplifies the rotation angle detection signal input to the input unit (sin, sing), and inputs the amplified rotation angle detection signal to the rotation angle detection signal input unit (sin). To do. The voltage of the rotation angle detection signal input to the input unit (sin) is Vsin, the voltage of the rotation angle detection signal input to the input unit (sing) is Vsing, and the voltage input to the rotation angle detection signal input unit (sin) Vmc is represented by the following Expression 3.
Vmc = {(r12 + r14) / r12} · {Vsin · r13 / (r11 + r13) + VB4 · r11 / (r11 + r13)} − Vsing · r14 / r12 (Equation 3)
Here, when r11 = r12 and r13 = r14,
Vmc = (Vsin−Vsing) · r13 / r11 + VB4
Thus, excluding the DC component power supply voltage VB4, the amplification factor of the rotation angle detection signal is inversely proportional to r11.

  The resistor r11 has resistors r111 and r112 connected in parallel. The resistor r111 is connected in series with the switch SW2 as an amplification factor switching unit. Since the switch SW2 is open when no cutoff signal is input, the resistance value of the resistor r11 is r11 = r112. On the other hand, since the switch SW2 is closed when a cutoff signal is input, the resistor r11 is in parallel with the resistors r111 and r112 (r11 = r111 · r112 / (r111 + r112)), and is proportional to the decrease in the resistance value of r11. As a result, the amplification factor increases. Therefore, even if the cutoff signal is output from the microcomputer 11 and the amplitude of the excitation signal is reduced, the amplification factor of the rotation angle detection signal is increased and input to the rotation angle detection signal input unit (sin) of the microcomputer 11. The amplitude of the rotation angle detection signal can be maintained.

  Note that the amplifying unit 15 performs the same operation as the amplifying unit 14, and thus the description thereof is omitted here.

In the first embodiment, the switches sw1 and sw2 have been described so that the amplification factor of the excitation signal and the amplification factor of the rotation angle detection signal can be switched in two stages. However, a resistor connected in series with the switch is used. The amplification factor may be switched to multiple stages by connecting in parallel in multiple stages and changing the resistance value in multiple stages. For example, in the case of performing power saving control in which the power source of the pre-driver IC 13 or the like is turned off stepwise in addition to the presence / absence of a cutoff signal, the amplification factor may be changed by switching the resistance according to the power saving step. . Moreover, you may switch in multiple steps according to the driving | running condition of the apparatus which generate | occur | produces noise around the resolver 3. FIG.
[Second Embodiment]
Next, a second embodiment will be described with reference to FIG. FIG. 2 is a configuration diagram illustrating an electric circuit of the resolver control device according to the second embodiment. In FIG. 2, the same parts as those in FIG.

  In FIG. 2, the microcomputer 41 includes an excitation signal switching unit that switches the amplification factor of the excitation signal and an amplification factor switching unit that switches the amplification factor of the rotation angle detection signal. The excitation signal switching unit and the amplification factor switching unit can be realized by causing the microcomputer 41 to execute a program stored in the microcomputer 41, for example. In the second embodiment, description will be made assuming that the program of the microcomputer 41 functions as an excitation signal switching unit and an amplification factor switching unit.

  The program of the microcomputer 41 changes the excitation signal switching unit to reduce the amplitude of the excitation signal output from the resolver excitation signal output unit (RSO) when the shutdown output unit (SDWN) outputs a cutoff signal. In the second embodiment, since the resistance value of the resistor r6 is not switched, the amplification factor by the operational amplifier OP1 determined by the resistors r6 and r4 is a fixed value.

  The program of the microcomputer 41 sets the amplification factor of the rotation angle detection signal input to the rotation angle detection signal input unit (sin, cos) when the shutdown output unit (SDWN) outputs a cutoff signal as an amplification factor switching unit. Make changes to increase. Since the resistance values of the resistors r11 and r12 are not switched in the second embodiment, the amplification factor by the operational amplifier OP2 determined by the resistors r11 to r14 is a fixed value.

  The amplification rate of the excitation signal and the rotation angle detection signal changed by the program of the microcomputer 41 is set in advance by an operation display device (not shown) connected to the resolver control device 1 and stored in a flash memory or the like inside the microcomputer 41, for example. You may keep it.

  Also in the second embodiment, the amplification factor may be switched in multiple stages as in the first embodiment.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to such specific embodiment, In the range of the summary of this invention described in the claim, Various modifications and changes are possible.

1 Resolver Control Device 11 Microcomputer 12 Photocoupler 13 Pre-driver IC
14, 15 Amplifier circuit 2 IGBT
3 Resolver 31 Excitation coil 32, 33 Detection coil 34 Rotor

Claims (1)

An input unit to which a rotation angle detection signal output from a resolver that detects a rotation angle of a motor driven by an inverter is input;
A control unit that outputs a cutoff signal that cuts off a drive output that drives the inverter;
An excitation signal switching unit that switches an amplitude of an excitation signal applied to the resolver when the control unit outputs the cutoff signal;
A resolver control device comprising: an amplification factor switching unit that switches an amplification factor of the rotation angle detection signal when the control unit outputs the cutoff signal.

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