# US 8,786,229 B2 · Power-consumption calculating method of motor driving device, and control method of motor driving device using the power-consumption calculating method

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- Number: US 8,786,229 B2
- Document ID: US8786229B2
- Status: Granted
- Kind: B2
- Application number: 13/382,200
- Filed: 2010-07-08
- Published: 2012-05-10
- Granted: 2014-07-22
- Earliest claimed: 2009-07-08
- Assignees: Meidensha Corporation
- Applicants: Takashi Yamaguchi; Toru Kakebayashi
- Inventors: Takashi Yamaguchi; Toru Kakebayashi
- Web page: https://patentgrep.com/patent/US8786229B2

## CPC

- H02P 23/0077: {Characterised by the use of a particular software algorithm}
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

Accurate power consumption is calculated without raising cost, or making the device bigger. Power consumption (P) upon driving a motor is calculated from an input voltage (Vdc), a switching duty factor of a switching device (SW1) of a chopper circuit (ch), which is provided with the switching device (SW1) and a reactor (Ldc), a reactor current (Idc), motor winding reactance (Lm), and motor rotation speed (N), in a motor driving device wherein: the input voltage (Vdc) inputted to the chopper circuit (ch) is stepped down by the chopper circuit (ch); DC power outputted by the chopper circuit (ch) is converted to AC power by driving an inverter (INV) with 120-degree conduction, and outputted to a motor (M); and surge voltage to be generated when the inverter (INV) undergoes commutation is clamped to the input voltage (Vdc), by a diode (D1) connected in inverse-parallel to the chopper circuit (ch).

## Claims

### Claim 1

A power consumption calculating method for a motor driving device configured to step down an input voltage inputted to a chopper circuit by the chopper circuit including a series circuit of a first switching element having one end connected to a positive voltage side of the inputted direct-current voltage, and a reactor having one end connected to the other end of the first switching element, and a second switching element disposed between the connection point between the other end of the first switching element and the one end of the reactor, and a negative voltage side of the input voltage, to convert a direct-current power outputted from the chopper circuit to an alternating-current power by driving an inverter by 120-degree conduction, to output to a motor, and to clamp a surge voltage generated at commutation of the inverter to the input voltage by a diode connected in inverse-parallel to the series circuit, the power consumption calculating method comprising:
calculating a power consumption of the motor driving device at driving of the motor by a following equation (a) from the input voltage to the chopper circuit, a switching duty factor representing a ratio of an ON state of the first switching element to an ON/OFF cycle of the first switching element, a reactor current flowing in the reactor, a winding reactance of the motor, and a rotational speed of the motor,
P
=
Vdc
×
BDuty
·
(
Idc
-
L
m
·
Idc
·
N
5
·
Vdc
·
Idc
3
)
(
a
)
P; power consumption
Vdc; input voltage
BDuty; switching element switching duty factor
Idc; reactor current
Lm; motor winding reactor
N; motor rotational speed.

### Claim 2 (depends on 1)

The power consumption calculating method for the motor driving device as claimed in claim 1, wherein a power consumption is calculated by multiplying the power consumption of the motor driving device calculated in the equation (a) by an efficiency of the inverter.

### Claim 3 (depends on 1)

A control method for the motor driving device by using the power consumption calculating method as claimed in claim 1, wherein a power control is performed by performing feedback of the power consumption of the motor driving device to an automatic controller.

### Claim 4

A control method for a motor driving device configured to step down an input voltage inputted to a chopper circuit by the chopper circuit including a series circuit of a first switching element having one end connected to a positive voltage side of the inputted direct-current voltage, and a reactor having one end connected to the other end of the first switching element, and a second switching element disposed between the connection point between the other end of the first switching element and the one end of the reactor, and a negative voltage side of the input voltage, to convert a direct-current power outputted from the chopper circuit to an alternating-current power by driving an inverter by 120-degree conduction, to output to a motor, and to clamp a surge voltage generated at commutation of the inverter to the input voltage by a diode connected in inverse-parallel to the series circuit, the control method comprising:
calculating a current command value by following equations (b) or (c) from the input voltage to the chopper circuit, a switching duty factor representing a ratio of an ON state of the first switching element to an ON/OFF cycle of the first switching element, a reactor current flowing in the reactor, a winding reactance of the motor, a rotational speed of the motor, a power consumption command value of the motor drive device, and an inverter efficiency, and
performing a power control by using this current command value,
Idc
ref
=
P
ref
Vdc
·
BDuty
+
L
m
·
Idc
·
N
5
·
Vdc
·
Idc
3
(
b
)
Idc
ref
=
P
ref
η
·
Vdc
·
BDuty
+
L
m
·
Idc
·
N
5
·
Vdc
·
Idc
3
(
c
)
Vdc; input voltage
BDuty; switching element switching duty factor
Idc; reactor current
Lm; motor winding reactor
N; motor rotational speed
Idcref; current command value
Pref; power consumption command value
η; inverter efficiency.