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Motor driving device

A technology for driving equipment and motors, applied in motor control, DC motor speed/torque control, electrical components, etc., to solve problems such as error detection

Inactive Publication Date: 2015-06-17
DENSO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the disconnection is falsely detected as the PWM oscillation to the load appears to be stopped

Method used

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Examples

Experimental program
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Effect test

no. 1 example

[0030] The following will refer to figure 1 The first embodiment is described through FIG. 4 . figure 1 is a block diagram showing the structure of a motor drive device 1 that drives a fan. The motor drive device 1 receives control commands from a higher-level control unit placed outside the motor drive device 1 . In the motor drive apparatus 1, the input processing circuit 3 of the internal control circuit 2 receives the control command. For example, the control command is provided as a PWM signal (duty signal) having a low frequency such as about 100 Hertz (Hz). The input processing circuit 3 generates a voltage signal by integrating the PWM signal, and sends the voltage signal to the operation processing circuit 4 .

[0031] Although not shown, the operation processing circuit 4 includes a circuit that generates a carrier wave such as a triangular wave. The operation processing circuit 4 generates a PWM output signal by comparing a voltage signal input thereto with a ca...

no. 2 example

[0061] will refer to Figure 5 to 7 describe the second embodiment. Similar components are denoted by like reference numerals, and descriptions thereof will not be repeated. Hereinafter, different structures will be mainly described.

[0062] Such as Figure 5 As shown in , the motor driving device 31 of the present embodiment is configured as a low-side driver for driving the motor 8 through the N-channel MOSFET 32 as the driving switching element T1. The source of N-channel MOSFET 32 is grounded. A series circuit of resistive element 10 and switch 11 , motor 8 and diode 9 are connected in parallel to each other between the positive terminal of battery 6 and the drain of N-channel MOSFET 32 . The potential at the drain corresponds to the output voltage Vm.

[0063] The average voltage detection circuit 12L of the control circuit 2L detects the voltage between the positive terminal of the battery 6 and the drain of the N-channel MOSFET 32 . The differential amplification...

no. 3 example

[0068] will refer to Figure 8 and 9 A third embodiment is described. Hereinafter, structures different from those of the first embodiment will be mainly described.

[0069] Such as Figure 8 As shown in , the motor drive device 41 of this embodiment has an N-channel MOSFET 42 as a return current path forming unit and a return current switching element T3 instead of the diode 9 of the motor drive device 1 in the first embodiment. In the control circuit 43 , the output signal of the operation processing circuit 4 is sent to the gate of the N-channel MOSFET 42 through the NOT gate 44 and the second drive circuit 45 to switch the operation of the N-channel MOSFET 42 .

[0070] When P-channel MOSFET 7 is in the off state, N-channel MOSFET 42 is turned on so that return current flows between the source and drain without passing through the body diode of N-channel MOSFET 42 . That is, the N-channel MOSFET 42 is used for synchronous rectification to reduce loss. When the low cur...

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Abstract

In a motor driving device, a driving switching element is connected in series with a motor between a power source and a ground, and operated by a PWM signal outputted from a control circuit. A return current path forming unit is connected in parallel with the motor to allow a return current when the driving switching element is turned off. A series circuit of a current flow restriction element and a switch is connected in parallel with the return current path forming unit. A disconnection determination unit prohibits output of the PWM signal and closes the switch of the series circuit when a voltage applied to the motor does not fluctuate according to the PWM signal, and determines the disconnection of the motor on condition that the voltage detected in that state indicates a change across a second threshold.

Description

technical field [0001] The present disclosure relates to a motor drive device that drives a motor through pulse width modulation (PWM) control. Background technique [0002] There is known a motor drive device that drives a motor as an inductive load by operating a semiconductor switching element such as a MOSFET connected in series with the motor under PWM control. Furthermore, in such a motor drive device, it has been proposed to have a function of detecting disconnection of the motor. For example, the disconnection of the motor is detected based on the fact that the current of the motor does not flow and the PWM signal is not output to the motor when the motor is disconnected. However, in this detection, in the case where the motor is used as a fan motor of a vehicle, if the motor rotates due to disturbance such as wind, an electromotive force is generated at the winding of the motor. Therefore, disconnection is falsely detected because the PWM oscillation to the load a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P7/29H02P7/291
CPCH02P7/29H02P29/0243
Inventor 岩宫广记
Owner DENSO CORP