DE112020004749T5 - CURRENT DETECTION DEVICE, ENGINE CONTROL DEVICE AND CURRENT DETECTION METHOD - Google Patents

Abstract

A current sensing device is a current sensing device having a first switching element and a second switching element connected in series and sensing a current flowing through an inverter configured to generate an AC signal, the current sensing device comprising: a first Rogowski coil, detecting a current flowing through the first switching element; a second Rogowski coil that detects a current flowing through the second switching element; and a detection processor that generates a composite signal obtained by adding a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal obtained by integrating an output of the second Rogowski coil , and detects an output current of an AC signal based on the composite signal.

Description

[Technical Field]

The present invention relates to a current detection device, a motor control device, and a current detection method.

[State of the art]

When driving a vehicle such as an electric car, it is necessary to drive a motor with a large current from a battery, and precise current detection is required in motor drive control. As a conventional technique for current detection, a technique using a Rogowski coil is known (see Patent Literature 1, for example). In such a conventional technique, the current value is estimated by linearly approximating the crest value of the Rogowski coil output.

[list of citations]

[patent literature]

[Patent Literature 1]

Republished Japanese Translation No. 2017/150726 of the PCT International Publication for Patent Applications

[Summary of the Invention]

[Technical Task]

However, in the conventional technique described above, since the error in the detected current value depends on the sampling period, precise current detection e.g. B. be difficult due to insufficient resolution of the sampling period.

The present invention was made to solve the above problem, and its object is to provide a current detection device, a motor control device, and a current detection method, by which a detection error of the current value due to an insufficient resolution of the sampling period can be reduced.

[Technical solution]

In order to solve the above problem, one aspect of the present invention is a current detection device that has a first switching element and a second switching element connected in series and detects a current that flows through an inverter that is configured to generate an AC signal, wherein the current detection device includes: a first Rogowski coil that detects a current flowing through the first switching element; a second Rogowski coil that detects a current flowing through the second switching element; and a detection processor that generates a composite signal obtained by adding a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal obtained by integrating an output of the second Rogowski coil , and detects an output current of an AC signal based on the composite signal.

Furthermore, an aspect of the present invention could be the above current detection device, in which the inverter includes a plurality of sets of the first switching element and the second switching element and generates AC signals with different phases from each other, which respectively correspond to the plurality of sets of the first switching element and the second switching element , the current sensing device includes the first Rogowski coil and the second Rogowski coil corresponding to the plurality of sets, respectively, and the sensing processor generates the composite signal corresponding to each of the plurality of sets and an output current for each of the AC signals with different Phases detected based on the composite signal.

Further, an aspect of the present invention could be the above current detection device, in which the detection processor detects a total value obtained by summing the first detection signals each corresponding to the plurality of sets as an input current of the inverter.

Further, an aspect of the present invention could be the above current detection device, in which the detection processor detects a negative current of an AC signal of a phase that is in a period of negative current among the plurality of AC signals with different phases based on an output current of a phase other than the detects a phase among the plurality of AC signals.

Furthermore, one aspect of the present invention is a current sensing device having a first switching element and a second switching element connected in series and sensing a current flowing through an inverter configured to generate an AC signal, the current sensing device comprising: a first Rogowski coil that detects a current flowing through the first switching element; a second Rogowski coil that detects a current flowing through the second switching element; and a detection processor that converts an output current of an AC signal based on a detection signal having a larger duty ratio for bringing a switching element into a conductive state between a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal, obtained by integrating an output of the second Rogowski coil.

Further, an aspect of the present invention could be the above current detection device, in which the detection processor generates a composite signal obtained by adding the first detection signal and the second detection signal, and an output current of the AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal with respect to the composite signal.

Further, an aspect of the present invention could be the above current detection device, in which the detection processor detects an output current of the AC signal in a period of a detection signal that has a larger duty ratio between the first detection signal and the second detection signal.

Further, an aspect of the present invention could be the above current detection device, in which the detection processor includes: a first integrating circuit having a reset function and integrating an output of the first Rogowski coil; and a second integrating circuit having a reset function that integrates an output of the second Rogowski coil.

Further, one aspect of the present invention is a motor control device including: the current detection device described above; an inverter that supplies the AC signal to a motor as a driving signal; and a motor controller that controls switching of the first switching element and the second switching element based on the output current detected by the current detection device.

Furthermore, one aspect of the present invention is a current detection method for detecting a current flowing through an inverter having a first switching element and a second switching element connected in series and generating an AC signal, the current detection method comprising: a first generating step for generating a first detection signal by a detection processor by integrating an output of a first Rogowski coil that detects a current flowing through the first switching element; a first generation step of generating a second detection signal by the detection processor by integrating an output of a second Rogowski coil that detects a current flowing through the second switching element; and a detection processing step of generating, by the detection processor, a composite signal obtained by adding the first detection signal generated in the first generation step and the second detection signal generated in the second generation step, and detecting an output current of an AC signal based on the composite signal.

Furthermore, one aspect of the present invention is a current detection method for detecting a current flowing through an inverter having a first switching element and a second switching element in connected in series and generates an AC signal, the current detection method comprising: a first generation step of generating a first detection signal by a detection processor by integrating an output of a first Rogowski coil that detects a current flowing through the first switching element; a first generation step of generating a second detection signal by the detection processor by integrating an output of a second Rogowski coil that detects a current flowing through the second switching element; and a detection processing step of detecting an output current of an AC signal by the detection processor based on a detection signal having a larger duty ratio for bringing a switching element into a conductive state between the first detection signal generated in the first generating step and the second detection signal generated in the second generating step.

[Advantageous Effects of the Invention]

According to the present invention, a current detection device includes a first Rogowski coil that detects a current flowing through a first switching element and a second Rogowski coil that detects a current flowing through a second switching element, and a detection processor generates a composite signal that is through Adding a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal obtained by integrating an output of the second Rogowski coil, and detects an output current of an AC signal based on the composite signals. Thereby, the current detecting device can generate the composite signal close to the actual waveform of the output current of an AC signal, and thus it is possible to reduce the detection error of the current value due to insufficient resolution of the sampling period. Consequently, the current detection device can realize precise current detection with a low-cost structure with a low resolution of the sampling period.

character list

• 1 14 is a block diagram showing an example of a motor control device according to a first embodiment.
• 2 12 is a block diagram showing an example of a detection processor in the first embodiment.
• 3 Fig. 12 is a circuit diagram showing an example of an integrating circuit in the first embodiment.
• 4 12 is a diagram for explaining the operation of a motor controller in the first embodiment.
• 5 12 is a diagram showing an example of the current waveform of the motor drive in the first embodiment.
• 6 Fig. 14 is a diagram for explaining composite signal generation processing in the first embodiment.
• 7 14 is a flowchart showing an example of output current detection processing by a current detection device according to the first embodiment.
• 8th 14 is a flowchart showing an example of the input current detection processing by the current detection device according to the first embodiment.
• 9 14 is a flowchart showing an example of the negative current detection processing by the current detection device according to the first embodiment.
• 10 Fig. 12 is a diagram showing an example of ringing of a detection signal.
• 11 14 is a block diagram showing an example of a motor control device according to a second embodiment.
• 12 14 is a flowchart showing an example of output current detection processing by a current detection device according to the second embodiment.
• 13 14 is a block diagram showing an example of a motor control device and a current detection device according to a third embodiment.

[Description of Embodiments]

Hereinafter, a current detection device, a motor control device, and a current detection method according to an embodiment of the present invention will be described with reference to the drawings.

[First embodiment]

1 14 is a block diagram showing an example of a motor control device 1 according to the present embodiment.

As in 1 shown, the motor control device 1 comprises a DC power supply 2, a smoothing capacitor 4, a current detection device 10, an inverter 20 and a motor controller 30.

In addition, the motor control device 1 is connected to a motor 3 .

The DC power supply 2 is, for example, a battery or the like, and supplies DC power to the motor control device 1 .

The motor 3 is, e.g 1 to be delivered.

The smoothing capacitor 4 is connected between a power supply line L1 connected to a positive pole of the DC power supply 2 and a ground line L2 connected to a negative pole of the DC power supply 2, and smoothes the DC voltage supplied from the DC power supply 2.

The inverter 20 generates AC signals (U-phase signal, V-phase signal, W-phase signal) for driving the motor 3 based on the control by the motor controller 30. The inverter 20 includes switching elements 21-1 to 21- 3 and switching elements 22-1 to 22-3. By switching the switching elements 21-1 to 21-3 and the switching elements 22-1 to 22-3, the inverter 20 generates, for example, three-phase sinusoidal current signals with phases shifted by 120 degrees as drive signals.

It should be noted that in the present embodiment, the switching elements 21-1 to 21-3 correspond to a high arm constituting an upper switching element (first switching element), and in a case where any upper switching element in the inverter 20 should be referred to, or referred to as switching elements 21 in a case where the switching elements are not particularly distinguished.

Further, the switching elements 22-1 to 22-3 correspond to a low arm constituting a lower switching element (second switching element), and are used in a case where any lower switching element in the inverter 20 is to be referred to or in a case , in which the switching elements are not particularly distinguished, referred to as switching elements 22.

A switching element 21 and a switching element 22 are connected in series between the power supply line L1 and the ground line L2 to form a full bridge circuit. Furthermore, the switching elements 21 (21-1 to 21-3) and the switching elements 22 (22-1 to 22-3) are, for example, N-type metal-oxide-semiconductor field-effect transistors (MOSFETs).

The switching element 21-1 and the switching element 22-1 are connected in series between the power supply line L1 and the ground line L2 to form a full bridge circuit that generates a U-phase signal that is a U-phase drive signal. The switching element 21-1 and the switching element 22-1 are switched based on control signals (S1, S2) output from the motor controller 30, and output a U-phase signal from a node N1 connected between the switching element 21-1 and the switching element 22-1 connected in series.

The switching element 21-2 and the switching element 22-2 are connected in series between the power supply line L1 and the ground line L2 to form a full bridge circuit having a V-phase signal nal is generated which is a V-phase drive signal. The switching element 21-2 and the switching element 22-2 are switched based on control signals (S3, S4) output from the motor controller 30 and output a V-phase signal from a node N2 connected between the switching element 21-2 and the switching element 22-2 connected in series.

The switching element 21-3 and the switching element 22-3 are connected in series between the power supply line L1 and the ground line L2 to form a full bridge circuit that generates a W-phase signal that is a W-phase drive signal. The switching element 21-3 and the switching element 22-3 are switched based on control signals (S5, S6) output from the motor controller 30 and output a W-phase signal from a node N3 connected between the switching element 21-3 and the switching element 22-3 connected in series.

As described above, the inverter 20 includes a plurality of sets of the switching element 21 and the switching element 22 and generates AC signals (U-phase signal, V-phase signal, W-phase signal) with phases different from each other, each of the plural of sets of the switching element 21 and the switching element 22 correspond.

The current detection device 10 detects a current flowing through the inverter 20 . The current detection device 10 detects an output current of a drive signal (AC signal) of each phase generated by the inverter 20, for example. In addition, the current detection device 10 detects an input current (input current of the inverter 20) from the DC power supply 2.

The current detection device 10 includes Rogowski coils 11-1 to 11-3, Rogowski coils 12-1 to 12-3 and a detection processor 13.

It should be noted that in the present embodiment, the Rogowski coils 11-1 to 11-3 are air-core coils that detect currents flowing through the switching elements 21 (21-1 to 21-3), and in a case in which shall be referred to as a Rogowski coil (first Rogowski coil) for any switching element 21 in the current detection device 10, or referred to as Rogowski coils 11 in a case where the Rogowski coils are not particularly distinguished.

Further, the Rogowski coils 12-1 to 12-3 are air-core coils that detect currents flowing through the switching elements 22 (22-1 to 22-3), and in a case where a Rogowski coil (second Rogowski coil) for any switching element 22 in the current sensing device 10, or referred to as Rogowski coils 12 in a case where the Rogowski coils are not particularly distinguished.

A Rogowski coil 11 (first Rogowski coil) detects a current flowing through a switching element 21 . The Rogowski coil 11-1 is arranged, for example, on a signal line connecting a drain of the switching element 21-1 and the power supply line L1, and detects a current flowing through the switching element 21-1. Further, the Rogowski coil 11-2 is arranged on a signal line connecting a drain of the switching element 21-2 and the power supply line L1, and detects a current flowing through the switching element 21-2. Furthermore, the Rogowski coil 11-3 is arranged on a signal line connecting a drain of the switching element 21-3 and the power supply line L1, and detects a current flowing through the switching element 21-3.

Also, for example, the Rogowski coil 12-1 is arranged on a signal line connecting a source of the switching element 22-1 and the ground line L2, and detects a current flowing through the switching element 22-1. Further, the Rogowski coil 12-2 is arranged on a signal line connecting a source of the switching element 22-2 and the ground line L2, and detects a current flowing through the switching element 22-2. Furthermore, the Rogowski coil 12-3 is arranged on a signal line connecting a source of the switching element 22-3 and the ground line L2, and detects a current flowing through the switching element 22-3.

As described above, the current detection device 10 includes the Rogowski coils 11 and the Rogowski coils 12 corresponding to the plural sets of the switching element 21 and the switching element 22, respectively.

The detection processor 13 is a processor that performs processing of detecting a current flowing through the inverter 20 . For example, the acquisition processor 13 generates a composite signal obtained by adding the first detection signal obtained by integrating the output of the Rogowski coil 11 and the second detection signal obtained by integrating the output of the Rogowski coil 12, and detects an output current of an AC signal based on the composite signal. The detection processor 13 generates a composite signal corresponding to each of the plurality of sets and detects an output current for each of the AC signals having different phases based on the composite signal. Specifically, the detection processor 13 outputs the generated composite signals as current signals representing output currents of drive signals (U-phase signal, V-phase signal, W-phase signal) of the motor 3 .

In addition, the detection processor 13 detects a total value obtained by summing the first detection signals corresponding to the plurality of sets of the switching element 21 and the switching element 22, respectively, as an input current of the inverter 20. Specifically, the detection processor 13 outputs an input current signal that has a Input current (input current of the inverter 20) depicts.

Furthermore, the detection processor 13 includes a negative current of a drive signal (AC signal) of a phase that is in a period of negative current among the plurality of drive signals (U-phase signal, V-phase signal, W-phase signal). different phases based on output currents of phases other than the one phase among the plurality of drive signals. For example, when the U-phase drive signal is in a period in which a negative current flows, the detection processor 13 adds the V-phase output current and the W-phase output current to calculate the negative current. The detection processor 13 outputs a negative current signal representing a negative current of a drive signal (AC signal).

It should be noted that details of the structure of the detection processor 13 will be described later with reference to FIG 2 to be discribed.

The motor controller 30 is, for example, a processor including a central processing unit (CPU) or the like, and controls the motor control device 1 integrally. The motor controller 30 controls switching of the switching element 21 and the switching element 22 based on the output current of a drive signal (AC signal) detected by the current detection device 10 .

The motor controller 30 includes, for example, an analog-to-digital (AD) converter (not shown), and converts the voltage of each current signal output from the detection processor 13 of the current detection device 10 into a current value to detect the current value. For example, the motor controller 30 detects the current value of the current signal output from the detection processor 13 via the AD converter, and detects a point (zero-crossing point) where the zero-crossing of the current occurs based on the current value of the current signal. The motor controller 30 controls switching of the switching element 21 and the switching element 22 based on the detected zero-cross point.

In addition, the motor controller 30 acquires, for example, the current value of the input current signal output from the acquisition processor 13 via the AD converter and acquires the maximum value of the current value of the input current signal. The motor controller 30 uses the maximum value of the detected current value for overcurrent detection. That is, when the maximum value of the detected current value becomes equal to or greater than a predetermined threshold value, the motor controller 30 determines that an overcurrent anomaly has occurred and performs anomaly processing such as stopping the driving of the motor 3 .

Further, the motor controller 30 acquires, for example, the current value of the negative current signal output from the acquisition processor 13 via the AD converter, and acquires the maximum value (negative current maximum value) of the current value of the negative current signal. The motor controller 30 uses the detected maximum negative current value for overcurrent detection. That is, when the detected negative current maximum value becomes equal to or larger than a predetermined threshold value, the motor controller 30 determines that an overcurrent anomaly has occurred and performs anomaly processing such as stopping the driving of the motor 3 .

Next, details of the structure of the detection processor 13 described above will be described with reference to FIG 2 described.
2 12 is a block diagram showing an example of the detection processor 13 in the present embodiment.

As in 2 1, the detection processor 13 includes integrator circuits 40-1 through 40-6, adders 50-1 through 50-6, and an adder 51.

It should be noted that in the present embodiment, the integrating circuits 40-1 to 40-6 have the same constitution, and in a case where any integrating circuit in the detection processor 13 is to be referred to or in a case where the Integrating circuits are not particularly distinguished, are referred to as integrating circuits 40.

In addition, the adders 50-1 to 50-6 have the same nature and are referred to as adders in a case where any adder is to be referred to in the detection processor 13 or in a case where the adders are not particularly distinguished 50 denoted.

The integrating circuit 40-1 is connected to the Rogowski coil 11-1 and outputs a detection signal UH obtained by integrating the output of the Rogowski coil 11-1. Further, the integrating circuit 40-2 is connected to the Rogowski coil 12-1 and outputs a detection signal UL obtained by integrating the output of the Rogowski coil 12-1.

Furthermore, the integrating circuit 40-3 is connected to the Rogowski coil 11-2 and outputs a detection signal VH obtained by integrating the output of the Rogowski coil 11-2. Further, the integrating circuit 40-4 is connected to the Rogowski coil 12-2 and outputs a detection signal VL obtained by integrating the output of the Rogowski coil 12-2.

Furthermore, the integrating circuit 40-5 is connected to the Rogowski coil 11-3 and outputs a detection signal WH obtained by integrating the output of the Rogowski coil 11-3. Further, the integrating circuit 40-6 is connected to the Rogowski coil 12-3 and outputs a detection signal WL obtained by integrating the output of the Rogowski coil 12-3.

The integrating circuits 40 (40-1 to 40-6) have a reset function and integrate the outputs of the Rogowski coils (11, 12). The detailed structure of the integrator circuits 40 is discussed herein with reference to FIG 3 described.
3 12 is a circuit diagram showing an example of an integrating circuit 40 in the present embodiment.

As in 3 shown, an integrating circuit 40 comprises a resistor 41, an operational amplifier 42, a capacitor 43 and a reset switch 44.

The resistor 41 is connected between one end of a Rogowski coil 11 (12) and an inverting input terminal of the operational amplifier 42. FIG. In addition, the capacitor 43 is connected between an inverting input terminal (node N5) of the operational amplifier 42 and an output terminal (node N5) of the operational amplifier 42. FIG.

The operational amplifier 42 operates as an integrating circuit by connecting the resistor 41 and the capacitor 43. In the operational amplifier 42, one end of a Rogowski coil 11(12) is connected to an inverting input terminal via a resistor 41, and the other end of the Rogowski coil 11(12) is connected to a non-inverting input terminal. The operational amplifier 42 uses the output of a Rogowski coil 11(12) as an input signal (IN), and outputs an output signal (OUT) obtained by integrating the output of the Rogowski coil 11(12).

The reset switch 44 is connected between an inverting input terminal (node N4) of the operational amplifier 42 and an output terminal (node N5) of the operational amplifier 42 in parallel with the capacitor 43. The reset switch 44 is a switch that resets the output potential of the integrating circuit 40, and the conductive state is controlled by a pulse signal based on the control signal S, for example. It should be noted that the reset switch 44 is controlled to be in a conductive state (ON state) when the integrator circuit 40 is reset.

It should be noted that the integrator circuit 40 operates as an integrator circuit when the reset switch 44 is controlled by the control signal S to be in a non-conductive state (OFF state).

Moreover, the control signal S is controlled by the motor controller 30 such that, for example, the integrating circuit 40 is reset when the switching of the switching element 21 and the switching element 22 described above is interrupted, and the integrating circuit 40 operates when the switching element 21 and the Switching element 22 are switched.

Furthermore, in 2 the integrating circuit 40-1, the integrating circuit 40-3 and the integrating circuit 40-5 of the first integrating circuit, and the detection signal UH, the detection signal VH and the detection signal WH correspond to the first detection signal. Furthermore, the integrating circuit 40-2, the integrating circuit 40-4 and the integrating circuit 40-6 correspond to the second integrating circuit, and the detection signal UL, the detection signal VL and the detection signal WL correspond to the second detection signal.

The adder 50 is an analog two-input adder and is realized by, for example, an adder circuit using an operational amplifier. The adder 50 outputs a composite signal obtained by adding two input signals.

For example, the detection signal UH and the detection signal UL are supplied to the adder 50-1 as two input signals, and the adder 50-1 outputs a composite signal obtained by adding the detection signal UH and the detection signal UL as a U-phase Current signal UC off.

Also, the detection signal VH and the detection signal VL are supplied to the adder 50-2 as two inputs, and the adder 50-2 outputs a composite signal obtained by adding the detection signal VH and the detection signal VL as a V-phase current signal VC off.

Furthermore, the detection signal WH and the detection signal WL are supplied to the adder 50-3 as two input signals, and the adder 50-3 outputs a composite signal obtained by adding the detection signal WH and the detection signal WL as a W-phase Power signal toilet off.

As described above, the detection processor 13 generates composite signals (U-phase current signal UC, V-phase current signal VC, W-phase current signal WC) corresponding to the plurality of sets of the switching element 21 and the switching element 22, respectively, and detects the output current for each of the drive signals (AC signals) having different phases based on the composite signals. That is, the detection processor 13 outputs the generated composite signals (U-phase current signal UC, V-phase current signal VC, W-phase current signal WC) as current signals which are output currents for the drive signals (U-phase signal, V-phase signal, W-phase signal).

In addition, the V-phase current signal VC and the W-phase current signal WC are supplied to the adder 50-4 as two input signals, and the adder 50-4 outputs a composite signal obtained by adding the V-phase current signal VC and of the W-phase current signal WC is obtained as a U-phase negative current signal UMC. That is, the adder 50-4 outputs the negative current of the U-phase signal, which is in a period of negative current, as the U-phase negative current signal UMC based on output currents (V-phase current signals VC and W- Phase current signal WC) from phases except the U phase.

In addition, the U-phase current signal UC and the W-phase current signal WC are supplied to the adder 50-5 as two input signals, and the adder 50-5 outputs a composite signal obtained by adding the U-phase current signal UC and the W-phase current signal WC is obtained as a V-phase negative current signal VMC. That is, the adder 50-5 outputs the negative current of the V-phase signal, which is in a period of a negative current, as the V-phase negative current signal VMC based on output currents (U-phase current signals UC and W- phase current signal WC) from phases except the V phase.

Further, the U-phase current signal UC and the V-phase current signal VC are supplied to the adder 50-6 as two input signals, and the adder 50-6 outputs a composite signal obtained by adding the U-phase current signal UC and of the V-phase current signal VC is obtained as a W-phase negative current signal WMC. That is, the adder 50-6 outputs the negative current of the W-phase signal, which is in a period of negative current, as the W-phase negative current signal WMC based on output currents (U-phase current signal UC and V- Phase current signal VC) from phases except W phase.

As described above, the detection processor 13 detects a negative current of a drive signal of a phase that is in a period of negative current among the drive signals of three phases (U-phase signal, V-phase signal, W-phase signal). based on output currents (current signals) of phases other than the one phase among the plurality of drive signals. The detection processor 13 outputs the generated negative current signals (U-phase negative current signal UMC, V-phase negative current signal VMC, W-phase negative current signal WMC) as current signals each representing a negative current for a drive signal.

The adder 51 is an analog three-input adder and is realized by, for example, an adder circuit using an operational amplifier. The adder 51 outputs a composite signal obtained by adding three input signals. The detection signal UH, the detection signal VH and the detection signal WH are supplied to the adder 51 as three input signals, and the adder 51 outputs a composite signal obtained by adding the detection signal UH, the detection signal VH and the detection signal WH as an input current signal BTC .

As described above, the detection processor 13 detects the total value obtained by summing three first detection signals (detection signal UH, detection signal VH and detection signal WH) as the input current of the inverter 20. That is, the detection processor 13 outputs the input current signal BTC as a current signal that represents the input current.

Next, the operation of the motor control device 1 and the current detection device 10 according to the present embodiment will be described with reference to the drawings.

First, a shift operation by the motor controller 30 is explained with reference to FIG 4 and 5 described.

4 12 is a diagram for explaining the operation of the motor controller 30 in the present embodiment. Furthermore 5 12 is a diagram showing an example of the current waveform of the motor drive in the present embodiment.

In 4 “Drive state” denotes the state of a drive signal in a case where a cycle is set to 360 degrees, and is divided into six states ST1 to ST6. The motor controller 30 executes the in 4 switching control shown and a 180 degree excitation control.

Also, “U-phase high arm” denotes the control of the upper switching element 21-1 for U-phase, and “U-phase low arm” denotes the control of the lower switching element 22-1 for U-phase. Further, “V phase high arm” denotes the control of the upper switching element 21-2 for the V phase, and “V phase low arm” denotes the control of the lower switching element 22-2 for the V phase. Furthermore, “W phase high arm” denotes the control of the upper switching element 21-3 for the W phase, and “W phase low arm” denotes the control of the lower switching element 22-3 for the W phase.

As in 4 1, in the period from a state ST1 to a state ST3 as control of the U-phase drive signal, the motor controller 30 switches the switching element 21-1 and the switching element 22-1 by the control signal S1 and the control signal S2. Here, "SW" denotes a switching process by pulse width modulation (PWM) and "/SW" denotes inversion control of switching by "SW". Also, in the period from a state ST4 to a state ST6, the motor controller 30 turns off the switching element 21-1 by the control signal S1 and turns on the switching element 22-1 by the control signal S2 as control of the U-phase drive signal.

Further, in the period from a state ST3 to a state ST5, as control of the V-phase drive signal, the motor controller 30 switches the switching element 21-2 and the switching element 22-2 by the control signal S3 and the control signal S4. Also, in the period of a state ST6, a state ST1, and a state ST2 as control of the V-phase drive signal, the motor controller 30 turns off the switching element 21-2 by the control signal S3 and turns on the switching element 22-2 by the control signal S4.

Further, in the period of a state ST5, a state ST6 and a state ST1 as control of the W-phase drive signal, the motor controller 30 switches the switching element 21-3 and the switching element 22-3 by the control signal S5 and the control signal S6. Also, in the period from a state ST2 to a state ST4, as control of the W-phase drive signal, the motor controller 30 turns off the switching element 21-3 by the control signal S5 and turns on the switching element 22-3 by the control signal S6.

Furthermore, forms in 5 waveform W1 depicts the U-phase current waveform, waveform W2 depicts the W-phase current waveform, and waveform W3 depicts the W-phase current waveform.

By executing the switching control described above, which is described in 4 , the motor controller 30 provides the motor 3 with a drive signal having a current waveform as shown in waveforms W1 through W3 in FIG 5 is shown to drive the motor 3.

Next, the current signal generation processing by the detection processor 13 of the current detection device 10 will be described with reference to FIG 6 described.
6 Fig. 14 is a diagram for explaining composite signal generation processing in the present embodiment.

In 6 a waveform W4 depicts the voltage waveform of the detection signal UH and a waveform W5 depicts the voltage waveform of the detection signal UL. Further, a waveform W6 depicts the voltage waveform of the U-phase current signal UC.

As in 6 As shown, the integrator circuit 40-1 of the detection processor 13 integrates the output of the Rogowski coil 11-1 and outputs a detection signal UH as shown in the waveform W4. Also, the integrating circuit 40-2 of the detection processor 13 integrates the output of the Rogowski coil 12-1 and outputs a detection signal UL as shown in the waveform W5.

Next, the adder 50-1 outputs a U-phase current signal UC as shown in waveform W6 as a composite signal obtained by adding the detection signal UH as shown in waveform W4 and the detection signal UL as shown in FIG represented by the waveform W5 is obtained. This U-phase current signal UC is a signal obtained by converting the output current (positive current) of the U-phase drive signal into a voltage.

It should be noted that the detection processor 13 also generates and outputs the V-phase current signal VC and the W-phase current signal WC in a manner similar to the U-phase current signal UC. That is, the detection processor 13 generates the U-phase current signal UC, the V-phase current signal VC, and the W-phase current signal WC using the following equations (1) to (3).

$$\text{u}-\text{phases}-\text{Current signal UC}=\text{Detection signal UH}+\text{Detection signal UL}$$

$$\text{V}-\text{phases}-\text{Current signal VC}=\text{detection signal VH}+\text{detection signal VL}$$

$$\text{W}-\text{phases}-\text{Power signal toilet}=\text{detection signal WH}+\text{detection signal WL}$$

The motor controller 30 acquires the U-phase current signal UC, the V-phase current signal VC and the W-phase current signal WC generated by the acquisition processor 13 via an AD converter (not shown) and uses the current signals to convert to detect the zero crossing point of the output current of each phase. The engine controller 30 performs the above-described in 4 shown shift control based on the detected zero-crossing points.

In addition, the detection processor 13 generates the U-phase negative current signal UMC, the V-phase negative current signal VMC, and the W-phase negative current signal WMC using the following equations (4) to (6).

$$\begin{array}{l}\begin{array}{l}\text{u}-\text{phases}-\text{Negative current signal UMC}=\text{V}-\text{phases}-\text{Current signal VC}+\text{W}-\text{phases}-\hfill \\ \text{Power signal toilet}\hfill \\ =\text{detection signal VH}+\text{detection signal VL}+\text{detection signal WH}\hfill \\ +\text{detection signal WL}\hfill \end{array}\\ \end{array}$$

$$\begin{array}{l}\text{V}-\text{phases}-\text{Negative current signal VMC}=\text{u}-\text{phases}-\text{Current signal UC}+\text{W}-\text{phases}-\\ \text{Power signal toilet}\\ =\text{Detection signal UH}+\text{Detection signal UL}+\text{detection signal WH}\\ \text{+ detection signal WL}\end{array}$$

$$\begin{array}{l}\text{W}-\text{phases}-\text{Negative current signal WMC}=\text{u}-\text{phases}-\text{Current signal UC}+\text{V}-\text{phases}-\\ \text{Current signal VC}\\ =\text{Detection signal UH}+\text{Detection signal UL}+\text{detection signal VH}\\ \text{+ detection signal VL}\end{array}$$

For example, when the U-phase negative current signal UMC is generated, the current value of the U-phase negative current signal UMC (current value Iu of the in 5 shown waveform W1) to an addition value of the current value Iv in 5 waveform W2 shown and the current value Iw of the in 5 shown waveform W3. Therefore, the detection processor 13 generates the U-phase negative current signal UMC using Equation (4) described above. That is, the adder 50-4 of the detection processor 13 adds the V-phase current signal VC and the W-phase current signal WC to generate the U-phase negative current signal UMC.

The motor controller 30 acquires the U-phase negative current signal UMC, the V-phase negative current signal VMC and the W-phase negative current signal WMC generated by the acquisition processor 13 via an AD converter (not shown) and uses the maximum value of a negative current signal each phase for anomaly detection (e.g. overcurrent detection) in a negative current period.

In addition, the detection processor 13 generates the input current signal BTC using the following equation (7). That is, the adder 51 of the detection processor 13 produces a total value obtained by adding the detection signal UH, the detection signal VH and the detection signal WH as the input current signal BTC.

$$\begin{array}{l}\text{Input current signal BTC}=\text{Detection signal UH}+\text{detection signal VH}\\ +\text{detection signal WH}\end{array}$$

The motor controller 30 acquires the input current signal BTC generated by the detection processor 13 via an AD converter (not shown) and uses the maximum value of the input current signal BTC to detect anomalies (e.g. overcurrent detection).

Next, a method of current detection by the current detection device 10 according to the present embodiment will be explained with reference to FIG 7 until 9 described.

7 14 is a flowchart showing an example of the output current detection processing by the current detection device 10 according to the present embodiment.

As in 7 1, when detecting an output current (positive current) of each phase of the inverter 20, the current detector 10 first integrates the output of the upper Rogowski coil 11 to generate a first detection signal (step S101). For example, in the detection processor 13 of the current detection device 10, the integrating circuit 40-1 integrates the output of the Rogowski coil 11-1 to generate a detection signal UH, and the integrating circuit 40-3 integrates the output of the Rogowski coil 11-2 to generate to generate detection signal VH. Also, the integrating circuit 40-5 integrates the output of the Rogowski coil 11-3 to generate a detection signal WH.

Next, the current detection device 10 integrates the output of the lower Rogowski coil 12 to generate a second detection signal (step S102). For example, in the detection processor 13, the integrator 40-2 integrates the output of the Rogowski coil 12-1 to generate a detection signal UL, and the integrator 40-4 integrates the output of the Rogowski coil 12-2 to generate a detection signal VL generate. Also, the integrating circuit 40-6 integrates the output of the Rogowski coil 12-3 to generate a detection signal WL.

It should be noted that the detection processor 13 could execute the processing of step S101 and the processing of step S102 in reverse order, or execute the processing in parallel, for example, by using the processing shown in FIG 2 structure shown is used.

Next, the current detection device 10 adds the first detection signal and the second detection signal to generate a composite signal (step S103). For example, in the detection processor 13, the adder 50-1 adds the detection signal UH and the detection signal UL to generate a U-phase current signal UC as a composite signal. Also, the adder 50-2 adds the detection signal VH and the detection signal VL to generate a V-phase current signal VC as a composite signal. Further, the adder 50-3 adds the detection signal WH and the detection signal WL to generate a W-phase current signal WC as a composite signal.

Next, the current detection device 10 detects the output current based on the composite signal (step S104). For example, the detection processor 13 outputs the U-phase current signal UC, the V-phase current signal VC, and the W-phase current signal WC to the motor controller 30 as current signals representing the output currents of the respective phases. After the processing of step S104, the current detection device 10 ends the output current detection processing.

It should be noted that the current detection device 10 repeatedly executes the processing from step S101 to step S103. In addition, although the detection processor 13 detects the output currents of three phases in parallel in the above description, the output currents of the respective phases could be detected independently. For example, the detection processor 13 could detect the output current through the above processing only in a period in which each phase has a positive current.

Next, the input current detection processing by the current detection device 10 according to the present embodiment will be explained with reference to FIG 8th described.

8th 12 is a flowchart showing an example of the input current detection processing by the current detection device 10 according to the present embodiment.

As in 8th 1, when performing the input current detection processing, the current detection device 10 first integrates the output of the upper Rogowski coil 11 of each phase to generate a first detection signal of each phase (step S201). For example, in the detection processor 13 of the current detection device 10, the integrating circuit 40-1 integrates the output of the Rogowski coil 11-1 to generate a detection signal UH, and the integrating circuit 40-3 integrates the output of the Rogowski coil 11-2 to generate to generate detection signal VH. Also, the integrating circuit 40-5 integrates the output of the Rogowski coil 11-3 to generate a detection signal WH.

Next, the current detection device 10 adds the first detection signals of the respective phases to generate an input current signal (step S202). For example, in the detection processor 13, the adder 51 adds the detection signal UH, the detection signal VH and the detection signal WH to generate an input current signal BTC.

Next, the current detection device 10 detects the input current based on the input current signal (step S203). For example, the detection processor 13 outputs the input current signal BTC to the motor controller 30 as a current signal representative of the input current.

It should be noted that the current detection device 10 repeatedly executes the processing from step S201 to step S203.

Next, the negative current detection processing by the current detection device 10 according to the present embodiment will be explained with reference to FIG 9 described.

9 14 is a flowchart showing an example of the negative current detection processing by the current detection device according to the present embodiment.

As in 9 1, when performing the negative current detection processing, the current detection device 10 first generates composite signals of the respective phases (step S301). The current detection device 10 generates composite signals of the respective phases by the above-described in 7 illustrated processing from step S101 to step S103.

Next, the current detection device 10 adds composite signals of phases except for a phase in a period of a negative current to generate a negative current signal (step S302). The detection processor 13 of the current detection device 10 generates negative current signals of the respective phases using equations (4) to (6) described above. For example, in the detection processor 13, the adder 50-4 adds the V-phase current signal VC and the W-phase current signal WC to generate a U-phase negative current signal UMC. Also, the adder 50-5 adds the U-phase current signal UC and the W-phase current signal WC to generate a V-phase negative current signal VMC. Further, the adder 50-6 adds the U-phase current signal UC and the V-phase current signal VC to generate a W-phase negative current signal WMC.

Next, the current detection device 10 detects the negative current of an AC signal based on the negative current signal (step S303). For example, the detection processor 13 outputs the U-phase negative current signal UMC, the V-phase negative current signal VMC, and the W-phase negative current signal WMC to the motor controller 30 as current signals representing the negative current signals of the respective phases. After the processing of step S303, the current detection device 10 ends the negative current detection processing.

It should be noted that the current detection device 10 repeatedly executes the processing from step S301 to step S303. In addition, although the detection processor 13 detects the negative currents of three phases in parallel in the above description, the output currents of the respective phases could be detected independently. For example, the detection processor 13 could detect the negative current through the above processing only in a period in which each phase has a negative current.

As described above, the current detection device 10 according to the present embodiment is a current detection device that has the switching element 21 (first switching element) and the switching element 22 (second switching element) connected in series and detects a current flowing through the inverter 20 configured therefor is to generate an AC signal (drive signal), wherein the current detection device includes the Rogowski coil 11 (first Rogowski coil), the Rogowski coil 12 (second Rogowski coil), and the detection processor 13 . The Rogowski coil 11 detects a current flowing through the switching element 21 . The Rogowski coil 12 detects a current flowing through the switching element 22 . The detection processor 13 generates a composite signal obtained by adding the first detection signal obtained by integrating the output of the Rogowski coil 11 and the second detection signal obtained by integrating the output of the Rogowski coil 12, and detects an output current of an AC signal (drive signal) based on the composite signal.

Therefore, the current detection device 10 according to the present embodiment can generate a composite signal close to the actual waveform of the output current of an AC signal (drive signal), and thus it is possible to reduce the detection error of the current value due to insufficient resolution of the sampling period. Consequently, the current detection device according to the present embodiment can realize precise current detection with a low-cost structure with a low resolution of the sampling period.

Moreover, in the present embodiment, the inverter 20 includes a plurality of sets of the switching element 21 and the switching element 22, and generates AC signals (U-phase signal, V-phase signal, W-phase signal) having phases different from each other, each of which Plural sets of the switching element 21 and the switching element 22 correspond. The current detection device 10 includes the Rogowski coil 11 and the Rogowski coil 12, each of the plurality of sets of switching elements 21 and the switching element 22 correspond. The detection processor 13 generates composite signals (U-phase current signal UC, V-phase current signal VC, W-phase current signal WC) corresponding to the plurality of sets of the switching element 21 and the switching element 22, respectively, and detects the output current for each of the AC signals with different phases based on the composite signals.

Therefore, the current detection device 10 according to the present embodiment can accurately detect the output current for each of the AC signals (drive signals) of a plurality of phases (three phases: U-phase, V-phase and W-phase) with a low-cost structure with a low resolution of the sampling period.

Furthermore, in the present embodiment, the detection processor 13 detects a total value obtained by summing the first detection signals corresponding respectively to the plural sets of the switching element 21 and the switching element 22 as the input current of the inverter 20 .

Therefore, the current detection device 10 according to the present embodiment can also accurately detect the input current of the inverter 20 with an inexpensive structure. In addition, the motor control device 1 according to the present embodiment can detect an abnormality due to overcurrent with high accuracy by using the input current of the inverter 20 detected by the current detection device 10 .

Further, in the present embodiment, the detection processor 13 detects a negative current of an AC signal (drive signal) of a phase that is in a period of negative current among the plurality of AC signals (drive signals) having different phases based on output currents of phases other than the one phase among the majority of AC signals. For example, the detection processor 13 detects the maximum value of the addition value obtained by adding the output currents of the other phases as the maximum value of the negative current of an AC signal (drive signal).

Therefore, the current detection device 10 according to the present embodiment can detect the current of an AC signal (drive signal) in a period of a negative current with an inexpensive structure. In addition, the motor control device 1 according to the present embodiment can detect an abnormality due to overcurrent in a period of negative current with high accuracy by using the negative current of an AC signal (drive signal) detected by the current detector 10 .

Further, in the present embodiment, the detection processor 13 includes a first integrating circuit having a reset function (e.g., integrating circuit 40-1, integrating circuit 40-3, and integrating circuit 40-5) that integrates the output of the Rogowski coil 11, and a second integrating circuit with a reset function (e.g., integrator 40-2, integrator 40-4, and integrator 40-6) that integrates the output of Rogowski coil 12.

Therefore, the current detection device 10 according to the present embodiment can reset the integrating circuit 40 after each detection, and thus the output of the Rogowski coil 11 (12) can be integrated accurately. In addition, since the current detection device 10 according to the present embodiment includes the plurality of integrating circuits 40, the processing can be performed in parallel and the output current can be detected in real time.

Further, the motor control device 1 according to the present embodiment includes the current detection device 10, the inverter 20, and the motor controller 30 described above. The inverter 20 supplies the motor 3 with an AC signal as a drive signal. The motor controller 30 controls switching of the switching element 21 and the switching element 22 based on the output current detected by the current detection device 10 .

Therefore, the motor control device 1 according to the present embodiment offers an effect similar to that of the current detection device 10 described above, and can reduce the detection error of the current value due to insufficient resolution of the sampling period.

Further, the current detection method according to the present embodiment is a current detection method for detecting a current flowing through the inverter 20 using the switching element 21 and the switching element 22 are connected in series and generates an AC signal, wherein the current detection method comprises a first generation step, a second generation step and a detection processing step. In the first generation step, the detection processor 13 integrates the output of the Rogowski coil 11, which detects a current flowing through the switching element 21, to generate a first detection signal. In the first generation step, the detection processor 13 integrates the output of the Rogowski coil 12, which detects a current flowing through the switching element 22, to generate a second detection signal. In the detection processing step, the detection processor 13 generates a composite signal obtained by adding the first detection signal generated in the first generation step and the second detection signal generated in the second generation step, and detects an output current of an AC signal based on the composite signal.

Therefore, the current detection method according to the present embodiment offers an effect similar to that of the current detection device 10 and the motor control device 1 described above, and can reduce the detection error of the current value due to insufficient resolution of the sampling period.

[Second embodiment]

In the motor control device 1 of the first embodiment described above, at the rising edge of the detection signal obtained by integrating the output of a Rogowski coil (11, 12), due to the influence of the parasitic capacitance of a snubber circuit (not shown) and a switching element ( 21, 22) in the inverter 20 or the influence of the switching noise of the switching element (21, 22), ringing may occur.

10 Fig. 12 is a diagram showing an example of ringing of a detection signal.

In 10 A waveform W7 shows the voltage waveform of a detection signal UL of the Rogowski coil 12-1. In the motor control device 1 of the first embodiment, ringing may occur at the rising edge as in a period TR1 indicated in the waveform W7.

Therefore, in the first embodiment described above, in a case where the duty ratio for bringing a switching element (21, 22) into the conductive state is small, for example, the detection timing of the detection signal overlaps with the ringing occurrence period (e.g. period TR1 ), and therefore it is difficult to achieve precise current detection.

Therefore, in the present embodiment, a variant that reduces the influence of such ringing and realizes precise current detection is described.

11 12 is a block diagram showing an example of a motor control device 1a according to the second embodiment.

As in 11 As shown, the motor control device 1a includes a DC power supply 2, a smoothing capacitor 4, a current detector 10a, an inverter 20, and a motor controller 30a.

It should be noted that in 11 the same structure as in 1 is denoted by the same reference numeral and the description thereof is omitted.

The current detection device 10a detects a current flowing through the inverter 20, and includes Rogowski coils 11-1 to 11-3, Rogowski coils 12-1 to 12-3, and a detection processor 13a.

In the present embodiment, the structure of the detection processor 13a and the motor controller 30a is unique, and the structure will be described below.

The basic operation of the detection processor 13a is similar to that of the detection processor 13 of the first embodiment, except that detection processing for reducing the ringing described above is performed. The detection processor 13a detects an output current of an AC signal based on a detection signal having the larger one Duty ratio for bringing the switching element (21, 22) into the conductive state between the first detection signal obtained by integrating the output of the Rogowski coil 11 and the second detection signal obtained by integrating the output of the Rogowski coil 12 .

The detection processor 13a generates a composite signal obtained by adding the first detection signal and the second detection signal, and detects an output current of an AC signal in a period of a detection signal having a larger duty ratio between the first detection signal and the second detection signal with respect to the composite signal .

The acquisition processor 13a comprises a pre-acquisition processor 131 and a detector 132.

The pre-detection processor 131 generates a first detection signal from the outputs of the Rogowski coils 11 (11-1, 11-2 and 11-3), generates a second detection signal from the outputs of the Rogowski coils 12 (12-1, 12-2 and 12-3) and generates a composite signal obtained by adding the first detection signal and the second detection signal. The pre-acquisition processor 131 is, for example, the same circuit as the acquisition processor 13 of the first embodiment shown in FIG 2 is shown.

The detector 132 is part of the motor controller 30a, includes, for example, an AD converter (not shown), and detects a current value via the AD converter. Here, the signal obtained by converting the current waveform into the voltage includes a U-phase current signal UC, a V-phase current signal VC, a W-phase current signal WC, an input current signal BTC, a U-phase negative current signal UMC, a V --phase negative current signal VMC, a W-phase negative current signal WMC, and the like.

For example, when the current values of the U-phase current signal UC, the V-phase current signal VC, and the W-phase current signal WC are detected (detected), the detector 132 detects, as the current value, the voltage in a period of the detection signal with the larger one Duty ratio for bringing the switching element (21, 22) into the conductive state between the voltage in a period of the first detection signal before generation of the composite signal and the voltage in a period of the second detection signal. That is, the detector 132 detects the voltage in a period of the first detection signal before generating the composite signal and the voltage in a period of the second detection signal via the AD converter, compares the duty ratio in a period of the first detection signal with the duty ratio in one period of the second detection signal and adopts the larger voltage value as the current value.

It should be noted that, in order to reduce the influence of ringing, the detector 132, when detecting the voltage in a period of the first detection signal and the voltage in a period of the second detection signal, detects a voltage value in the middle part of a period of the conductive state of each Switching element (21, 22) detected.

The motor controller 30a is, for example, a processor including a CPU or the like, and integrally controls the motor control device 1a. The motor controller 30a controls the switching of the switching element 21 and the switching element 22 based on the output current of the drive signal (AC signal) detected by the current detection device 10a. The motor controller 30a performs control similar to that of the motor controller 30 of the first embodiment.

In addition, the motor controller 30a includes a detector 132 which is part of the detection processor 13a described above.

Next, operations of the current detection device 10a and the motor control device 1a according to the present embodiment will be described with reference to the drawings.

The basic operation of the current detection device 10a and the motor control device 1a according to the present embodiment is similar to that of the above-described first embodiment shown in FIG 7 until 9 is shown. It should be noted that in the present embodiment, since the processing of the in 7 illustrated step S104 is unique, the details of this processing with reference to FIG 12 to be discribed.

12 12 is a flowchart showing an example of the output current detection processing by the current detection device 10a according to the present embodiment. The processing shown in this figure corresponds to that in 7 illustrated processing of step S104.

As in 12 1, the detection processor 13a of the current detection device 10a first detects a detection signal of the Rogowski coil 11 (high side) (step S401). That is, the detector 132 of the detection processor 13a detects the voltage value of the middle part of one period of the first detection signal of the composite signal via an AD converter (not shown).

Then, the detection processor 13a first detects a detection signal of the Rogowski coil 12 (low side) (step S401). That is, the detector 132 detects the voltage value of the central part of one period of the second detection signal of the composite signal via an AD converter (not shown).

Next, the detector 132 determines whether the duty ratio (duty ratio) on the low side is larger than the duty ratio (duty ratio) on the high side (step S403). When the duty ratio (width of conduction period of switching element 22) on the low side is greater than the duty ratio (width of conduction period of switching element 21) on the high side (step S403: YES), the detector 132 advances the processing to step S404. Otherwise, when the duty ratio (width of conduction period of switching element 22) on the low side is equal to or smaller than the duty ratio (width of conduction period of switching element 21) on the high side (step S403: NO), the detector 132 advances the processing to step S405 before.

In step S404, the detector 132 selects the detection signal of the Rogowski coil 12 (low side) as the detection value of the output current. The detector 132 takes the voltage value of the middle part of one period of the second detection signal of the composite signal as a detection value of the output current. After the processing of step S404, the current detection device 10a ends the detection processing.

Further, in step S405, the detector 132 selects the detection signal of the Rogowski coil 11 (high side) as the detection value of the output current. The detector 132 takes the voltage value of the middle part of one period of the first detection signal of the composite signal as a detection value of the output current. After the processing of step S405, the current detection device 10a ends the detection processing.

It should be noted that the current detection device 10a is the one described above in 12 performs the processing shown for the U-phase current signal UC, the V-phase current signal VC and the W-phase current signal WC as current signals representing output currents of the respective phases.

As described above, the current detection device 10a according to the present embodiment is a current detection device that has the switching element 21 (first switching element) and the switching element 22 (second switching element) connected in series and detects a current flowing through the inverter 20 configured therefor is to generate an AC signal, the current detection device comprising the Rogowski coil 11 (first Rogowski coil), the Rogowski coil 12 (second Rogowski coil), and the detection processor 13a. The Rogowski coil 11 detects a current flowing through the switching element 21 . The Rogowski coil 12 detects a current flowing through the switching element 22 . The detection processor 13a detects an output current of an AC signal based on a detection signal having the larger duty ratio for bringing the switching element (21, 22) into the conductive state between the first detection signal obtained by integrating the output of the Rogowski coil 11 and the second detection signal obtained by integrating the output of the Rogowski coil 12.

Consequently, the current detection device 10a according to the present embodiment detects the output current by using the detection signal with a larger duty ratio (detection signal with a larger width) between the first detection signal and the second detection signal, and thus it is possible to detect the output current while avoiding the period of occurrence of to detect ringing. Therefore, the current detection device 10a according to the present embodiment can reduce the influence of ringing to realize precise current detection.

Further, in the present embodiment, the detection processor 13a generates a composite signal obtained by adding the first detection signal and the second detection signal, and detects an output current of an AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal in reference to the composite signal.

Therefore, the current detection device 10a according to the present embodiment can generate a composite signal close to the actual waveform of the output current of an AC signal (drive signal), and thus it is possible to reduce the detection error of the current value due to insufficient resolution of the sampling period. Consequently, the current detection device 10a according to the present embodiment can realize precise current detection with a low-cost structure with a low resolution of the sampling period as in the first embodiment.

Further, the motor control device 1a according to the present embodiment includes the current detection device 10a, the inverter 20, and the motor controller 30a described above. The inverter 20 supplies an AC signal to the motor 3 as a driving signal. The motor controller 30a controls switching of the switching element 21 and the switching element 22 based on the output current detected by the current detection device 10a.

Therefore, the motor control device 1a according to the present embodiment offers an effect similar to that of the current detection device 10a described above, and can reduce the influence of ringing to realize precise current detection.

Further, the current detection method according to the present embodiment is a current detection method for detecting a current flowing through the inverter 20 having the switching element 21 and the switching element 22 connected in series and generating an AC signal, the current detection method comprising a first generation step, a second generation step and includes a detection processing step. In the first generation step, the detection processor 13a integrates the output of the Rogowski coil 11 that detects a current flowing through the switching element 21 to generate a first detection signal. In the first generation step, the detection processor 13a integrates the output of the Rogowski coil 12, which detects a current flowing through the switching element 22, to generate a second detection signal. In the detection processing step, the detection processor 13a detects an output current of an AC signal based on a detection signal having a larger duty ratio for bringing the switching element into the conductive state between the first detection signal generated in the first generation step and the second detection signal generated in the second generation step.

Therefore, the current detection method according to the present embodiment offers an effect similar to that of the current detection device 10a and the motor control device 1a described above, and can reduce the influence of ringing to realize precise current detection.

[Third embodiment]

Next, a current detection device 10b and a motor control device 1b according to the third embodiment will be described with reference to the drawings.

In the present embodiment, a variant of the current detection device 10a and the motor control device 1a according to the second embodiment described above will be described. The present embodiment is a variant of a case where the first detection signal and the second detection signal are used without generating a composite signal.

13 12 is a block diagram showing an example of the motor control device 1b and the current detection device 10b according to the third embodiment.

As in 13 1, the motor control device 1b includes the current detection device 10b. Furthermore, the current detection device 10b includes a detection processor 13b. It should be noted that although in 13 not shown, the motor control device 1b includes a motor controller 30a, a DC power supply 2, a smoothing capacitor 4, and an inverter 20 comprises similar to those of the second embodiment described above, and that the motor controller 30a comprises a detector 132a.

The detection processor 13b detects an output current of an AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal. The detection processor 13b includes a pre-detection processor 131a and the detector 132a.

The pre-detection processor 131a comprises an integrating circuit 40-1 to an integrating circuit 40-6, and generates first detection signals (detection signal UH, detection signal VH and detection signal WH) from the outputs of the Rogowski coils 11 (11-1, 11-2, 11-3 ). Also, the pre-detection processor 131a generates second detection signals (detection signal UL, detection signal VL, and detection signal WL) from the outputs of the Rogowski coils 12 (12-1, 12-2, 12-3).

The detector 132a performs processing similar to that of the detector 132 by detecting detection signals (detection signal UH, detection signal VH, detection signal WH, detection signal UL, detection signal VL and detection signal WL) instead of the composite signals (U-phase current signal UC, V-phase -current signal VC, W-phase current signal WC) of the second embodiment is used. The detector 132a detects an output current of an AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal.

That is, the detector 132a detects the voltage of the first detection signal and the voltage of the second detection signal through the AD converter, compares the duty ratio of the first detection signal with the duty ratio of the second detection signal, and adopts the greater voltage value as the current value.

It should be noted that the operation of the current detection device 10b according to the present embodiment follows the processing of the second embodiment shown in FIG 12 is similar except that instead of the composite signals (U-phase current signal UC, V-phase current signal VC, W-phase current signal WC) the first detection signals (detection signal UH, detection signal VH and detection signal WH) and the second detection signals (detection signal UL, detection signal VL, and detection signal WL) are used directly, and therefore the description thereof is omitted here.

As described above, in the current detection device 10b and the motor control device 1b according to the present embodiment, the detection processor 13b detects an output current of an AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal.

Therefore, the current detection device 10b and the motor control device 1b according to the present embodiment offer an effect similar to that of the second embodiment and can reduce the influence of ringing to realize precise current detection.

It should be noted that the present invention is not limited to the above embodiments and can be modified without departing from the gist of the present invention.

For example, although in the above embodiments, an example has been described in which the current detection device 10 (10a, 10b) is included in the motor control device 1 (1a, 1b) and used for current detection for controlling driving of the motor 3, the present invention is not limited thereto. For example, the current detection device 10 (10a, 10b) could be used for current detection of an inverter used for a power supply device or the like other than the motor control device 1 (1a, 1b).

Moreover, although in the first embodiment an example was described in which the detection processor 13 outputs a signal obtained by converting a current waveform into a voltage and the motor controller 30 detects a current value via an AD converter (not shown), the present invention is not limited thereto. Here, the signal obtained by converting the current waveform into the voltage includes a U-phase current signal UC, a V-phase current signal VC, a W-phase current signal WC, an input current signal BTC, a U-phase negative current signal UMC, a V -phase- negative current signal VMC, a W-phase negative current signal WMC, and the like. For example, the acquisition processor 13 could include an AD converter. That is, the acquisition processor 13 could have some of the functions of the motor controller 30. Furthermore, the motor controller 30 could have some or all of the functions of the detection processor 13 .

Further, although an example in which the detection processor 13a (13b) includes the detector 132 (132a) included in the motor controller 30a has been described in the second and third embodiments, the present invention is not limited thereto. For example, the detector 132 (132a) could be external to the motor controller 30a. That is, the acquisition processor 13a (13b) could have some of the functions of the motor controller 30a. Furthermore, the motor controller 30a could have some or all of the functions of the acquisition processor 13a (13b).

Further, although in the above embodiments, an example was described in which the current detecting device 10 (10a, 10b) detects a current corresponding to AC signals of three phases, the present invention is not limited thereto, and the present invention could be applied to applications with less as three phases or with four or more phases.

Further, although in the above embodiments an example was described in which the detection processor 13 (13a, 13b) is implemented by hardware processing with a circuit such as the integrating circuit 40 and the adder (50, 51), the present invention is not thereon limited, and some or all of the functions of the acquisition processor 13 (13a, 13b) could be implemented by software processing.

It should be noted that each structure included in the motor control device 1 (1a, 1b) described above has a computer system. In addition, a program for implementing the function of each structure included in the engine control device 1 described above could be recorded on a computer-readable recording medium, and the program recorded on this recording medium could be read and executed by a computer system for processing in each of the engine control device described above 1 (1a, 1b) contained structure to perform. Here, “a program recorded on a recording medium is read and executed by a computer system” implies that a program is installed in a computer system. Here, the "computer system" includes an operating system or hardware such as a peripheral device.

Additionally, the “computer system” could include a plurality of computing devices connected through a network that includes a communication line such as the Internet, a WAN, a LAN, or a leased line. Further, the “computer-readable recording medium” refers to a portable medium such as a floppy disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built into a computer system. As described above, the recording medium storing the program could be a non-volatile recording medium such as a CD-ROM.

Furthermore, the recording medium also includes an internally or externally provided recording medium that can be accessed by a distribution server for distribution of the program. Note that another structure in which the program is divided into a plurality of parts, downloaded at different timings, and then combined by each structure included in the engine control device 1 (1a, 1b), or another distribution server could be used , which distributes each of the split programs. In addition, the "computer-readable recording medium" includes a medium that stores a program for a specified period of time, such as B. a volatile memory (RAM) within a computer system that serves as a server or client when the program is transmitted over a network. Also, the program could be used to perform some of the functions described above. Furthermore, the program could be a program that can implement the functions described above in combination with a program already recorded in a computer system, i.e. a so-called difference file (difference program).

Furthermore, some or all of the functions described above could be implemented as an integrated circuit, e.g. B. with large scale integration (LSI), be implemented. The functions described above could be performed individually by processors, or some or all of the functions could be integrated into a processor. In addition, the method of circuit integration is not limited to an LSI, but could be realized by a dedicated circuit or a general-purpose processor will. Furthermore, in a case where an integrated circuit technology replacing the LSI appears with the advance of semiconductor technology, an integrated circuit corresponding to the technology could be used.

Reference List

1, 1a, 1b

engine control device

2

DC power supply

3

engine

4

smoothing capacitor

10, 10a, 10b

current sensing device

11, 11-1, 11-2, 11-3, 12, 12-1, 12-2, 12-3

Rogowski coil

13, 13a, 13b

acquisition processor

20

inverter

21, 21-1, 21-2, 21-3, 22, 22-1, 22-2, 22-3

switching element

30, 30a

engine controller

40, 40-1, 40-2, 40-3, 40-4, 40-5, 40-6

integrating circuit

41

Resistance

42

operational amplifier

43

capacitor

44

reset switch

50, 50-1, 50-2, 50-3, 50-4, 50-5, 50-6, 51

adder

131, 131a

pre-acquisition processor

132, 132a

detector

Claims (11)

A current sensing device having a first switching element and a second switching element connected in series and sensing a current flowing through an inverter configured to generate an AC signal, the current sensing device comprising: a first Rogowski coil that detects a current flowing through the first switching element; a second Rogowski coil that detects a current flowing through the second switching element; and a detection processor that generates a composite signal obtained by adding a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal obtained by integrating an output of the second Rogowski coil, and detects an output current of an AC signal based on the composite signal. current detection device claim 1 , wherein the inverter includes a plurality of sets of the first switching element and the second switching element and generates AC signals having phases different from each other, which respectively correspond to the plurality of sets of the first switching element and the second switching element, the current detection device includes the first Rogowski coil and the second Rogowski coil each corresponding to the plurality of sets, and the detection processor generates the composite signal corresponding to each of the plurality of sets and detects an output current for each of the AC signals having different phases based on the composite signal. current detection device claim 2 , wherein the detection processor detects a total value obtained by summing the first detection signals each corresponding to the plurality of sets as an input current of the inverter. current detection device claim 2 or 3 wherein the detection processor detects a negative current of an AC signal of a phase that is in a period of a negative current among the plurality of AC signals having different phases based on an output current of a phase other than the one phase among the plurality of AC signals. A current sensing device having a first switching element and a second switching element connected in series and sensing a current flowing through an inverter configured to generate an AC signal, the current sensing device comprising: a first Rogowski coil that detects a current flowing through the first switching element; a second Rogowski coil that detects a current flowing through the second switching element; and a detection processor that converts an output current of an AC signal based on a detection signal having a larger duty ratio for bringing a switching element into a conductive state between a first detection signal obtained by integrating an output of the first Rogowski coil and a second detection signal that obtained by integrating an output of the second Rogowski coil. current detection device claim 5 , wherein the detection processor generates a composite signal obtained by adding the first detection signal and the second detection signal, and an output current of the AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal with respect to the composite signal detected. current detection device claim 5 , wherein the detection processor detects an output current of the AC signal in a period of a detection signal with a larger duty ratio between the first detection signal and the second detection signal. Current detection device according to one of Claims 1 until 7 wherein the acquisition processor comprises: a first integrator circuit having a reset function and integrating an output of the first Rogowski coil; and a second integrating circuit having a reset function that integrates an output of the second Rogowski coil. A motor control device comprising: the current detection device according to any one of Claims 1 until 8th ; the inverter that supplies the AC signal to a motor as a drive signal; and a motor controller that controls switching of the first switching element and the second switching element based on the output current detected by the current detection device. A current sensing method for sensing a current flowing through an inverter having a first switching element and a second switching element connected in series and generating an AC signal, the current sensing method comprising: a first generation step of generating a first detection signal by a detection processor by integrating an output of a first Rogowski coil that detects a current flowing through the first switching element; a first generation step of generating a second detection signal by the detection processor by integrating an output of a second Rogowski coil that detects a current flowing through the second switching element; and and a detection processing step of generating, by the detection processor, a composite signal obtained by adding the first detection signal generated in the first generation step and the second detection signal generated in the second generation step, and detecting an output current of an AC signal based on the composite signal. A current detection method for detecting a current flowing through an inverter having a first switching element and a second switching element connected in series and generating an AC signal, the current detection method comprising: a first generating step for generating a first detection signal by a detection processor by integrating an output of a first Rogowski coil that detects a current flowing through the first switching element; a first generation step of generating a second detection signal by the detection processor by integrating an output of a second Rogowski coil that detects a current flowing through the second switching element; and a detection processing step of detecting an output current of an AC signal by the detection processor based on a detection signal having a larger duty ratio for bringing a switching element into a conductive state between the first detection signal generated in the first generating step and the second detection signal generated in the second generating step.

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