JP2004325166A - Rotation angle detector - Google Patents

Abstract

A counter value of a counter in an R / D conversion IC is made to match a counter value of a counter in a motor control CPU without providing a serial I / F signal line.
Immediately after turning on a CPU power supply or immediately after returning from an instantaneous drop of the CPU power supply, a counter in the R / D conversion IC and a counter in the motor control CPU are reset. , And the counter value φ and the counter value の of the counters 20 and 30 match each other a predetermined time after the reset of the counter 20 is released.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation angle detection device that detects a rotation angle of a rotating machine such as an electric motor using a resolver.
[0002]
[Prior art]
[Patent Document] JP-A-11-337371.
[0003]
In the rotation angle detection device disclosed in the above-mentioned patent document, a serial I / F signal line is provided between an R / D conversion IC (resolver / digital converter) and a motor control CPU, and the counter value in the motor control CPU is set to this value. By setting the counter value in the R / D conversion IC obtained via the serial I / F signal line, the values of both counters are matched.
[0004]
[Problems to be solved by the invention]
In this conventional example, since a serial I / F signal line is provided, a dedicated circuit for the serial I / F signal is required in the R / D conversion IC, and the circuit scale is increased. A / F terminal and a circuit are required, and there is a problem that an increase in the rank of the motor control CPU hinders downsizing and cost reduction.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and is capable of rotating a counter value of an R / D conversion IC and a counter value of a motor control CPU without providing a serial I / F signal line. It is an object to provide an angle detection device.
[0006]
[Means for Solving the Problems]
In order to achieve this object, in the present invention, the power supply state of the rotation angle detecting means is detected, and it is detected that the power supply is turned on or that the voltage of the power supply has returned from a value lower than a predetermined value to a value higher than a predetermined value. In this case, the reset processing of the counters in the R / D conversion means and the rotation angle detection means is performed, and the reset release cancels the reset processing in the order of the counter in the rotation angle detection means and the counter in the R / D conversion means. Configuration.
[0007]
【The invention's effect】
According to the present invention, both the counter in the rotation angle detecting means and the counter in the R / D conversion means are reset after turning on the power of the rotation angle detecting means or returning from the sag, and the reset release is performed when the rotation angle is detected. With a simple configuration in which the reset processing is canceled in the order of the counter in the means and the counter in the R / D conversion means, the counter value in the rotation angle detection means can be matched with the counter value in the R / D conversion means.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, those having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.
[0009]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram showing a first embodiment of the present invention. The configuration of the first embodiment will be described with reference to FIG. An excitation signal f (t) is input to the primary winding of the resolver 1, and amplitude modulation is performed in accordance with the rotation angle θ of the motor in which the resolver 1 is attached to the secondary winding arranged with a phase difference of 90 °. The obtained signals are sin θ · f (t) and cos θ · f (t). The R / D conversion IC 2 (R / D conversion means) is provided with an UP / DOWN counter 20 (first counter) indicating the conversion result φ of the rotation angle θ indicated by the resolver 1. f (t) and two signals of cosθ · f (t) and two functions sinφ and cosφ obtained from the conversion result φ are generated by the sinφ / cosφ generating means 26, and the product-sum operation (multiplier 21, subtractor 22) Then, after obtaining sin (θ−φ) · f (t), the synchronous detection means 23 is used for the excitation signal f (t) to obtain the difference sin (θ) between the rotation angle θ and the counter value φ of the counter 20. −φ) is required. By increasing or decreasing the counter value φ, the feedback operation circuit is provided with a counter 20, a sinφ / cosφ generating means 26, a product-sum operation (multiplier 21, subtractor 22), a synchronous detection means 23, and a compensation so that the value becomes zero. The counter value φ matches the rotation angle θ. The counter value φ is output by the encoder I / F 27 (three-phase signal output means) at the timing when the A and B signals indicating the rotation direction and the rotation amount of the shaft and the rotation angle cross zero (the rising edge of the U-phase signal). The Z signal is output as three-phase U, V, and W signals obtained from the absolute angle. The power-on reset circuit 28 (third reset means) is a reset circuit provided to initialize itself when the power supply 4 for the R / D conversion IC (power supply for the R / D conversion means) is turned on.
[0010]
The counter 30 (second counter) in the motor control CPU 3 (rotation angle detecting means) receives the A, B, and Z signals from the encoder I / F 27, and counts by measuring the number of edges of the A and B signals. By reading the rotation amount and resetting the counter 30 with the Z signal, the counter value φ and the counter value の of the counter 30 can be matched. However, since the Z signal is not output in the initial state immediately after the power is turned on, the counter value φ does not match the counter value ψ. The motor is controlled by the state of the counter 30. The rotation angle estimation means 32 roughly estimates the rotation angle from the U, V, and W signals. The reset sequence generation means 34 (first reset means, second reset means and reset release means) are provided with a reset 81 of the counter 20 and a counter 30 in response to an instruction from the power-on / sag detection means 33 (power state detection means). 83 and reset cancellations 82 and 84 of the counters 20 and 30. The power-on / sag detection means 33 turns on the power of the CPU power supply 5 (the power supply for the rotation angle detection means) and returns the voltage of the CPU power supply 5 from a value lower than a predetermined value in a state where the voltage has dropped due to a voltage sag or the like to a predetermined value or more. Detect that it has done. The comparative diagnosis means 31 (abnormality determination means) compares the output of the rotation angle estimation means 32 with the counter value ψ to determine whether or not the rotation angle detection device is abnormal.
[0011]
FIG. 2 is a time chart showing the operation of the first embodiment, and FIG. 3 is a flowchart showing the operation of the motor control CPU 3 of the first embodiment. The operation of the first embodiment will be described with reference to FIGS. First, the initialization following operation of the R / D conversion IC 2 will be described with reference to FIG. Since the R / D conversion IC 2 is initialized by the power-on reset circuit 28 in order to initialize the inside of the R / D conversion IC 2 when the power supply 4 for the R / D conversion IC is turned on, the counter value φ of the counter 20 is a resolver. Since it does not match the rotation angle θ (initial value: α), the counter value φ is increased or decreased after the power-on reset is released after the elapse of the power-on reset time b, and feedback is performed so as to match the resolver rotation angle θ (α). Operate. The counter value φ (α) matches the actual resolver rotation angle θ (α) after a predetermined period c has elapsed after the power-on reset is released by this feedback operation. The period from the release of the power-on reset until the resolver rotation angle θ (α) and the counter value φ (α) match is referred to as an initialization follow-up period c. In the initialization follow-up period c, the counter value φ monotonically increases or decreases from the reset state toward the resolver rotation angle θ. After the end of the initialization follow-up period c, even if the resolver rotation angle θ changes, the counter value φ changes by tracking the change, so that the resolver rotation angle θ and the counter value are always changed as long as the change amount does not exceed an allowable change amount. The difference between φ is almost zero, and can be regarded as coincident. When the conversion result of the R / D conversion IC 2 is used for motor control, it is general to use the counter value φ after the end of the initialization follow-up period c.
[0012]
Normally, the reset operation of the counter 20 is initialized by the power-on reset circuit 28. The total time t1 (for example, several tens ms) of the initialization (power-on reset time b) and the initialization follow-up period c is determined by the reset time t2 (for example, several tens ms) of the motor control CPU 3 and the motor control CPU 3 itself. In general, the counter value φ is equal to the resolver rotation angle at the time when the motor control CPU 3 starts the motor control, since it is generally sufficiently shorter than the total time of the initialization time t3 (for example, several hundred ms) by software. θ, the conversion value φ of the rotation angle required for motor control can be provided. However, with only the above operation, the counter value φ does not match the counter value 時 に at the start of motor control.
[0013]
Next, the operation of the motor control CPU 3 and the operations of the counters 20 and 30 will be described with reference to the flowchart of FIG. 3 and FIG. First, after turning on the power supply 4 for the R / D conversion IC and the CPU power supply 5 (or the voltage of the CPU power supply 5 has returned from a value lower than a predetermined value to a value equal to or higher than a predetermined value), resetting and initialization of the motor control CPU 3 are started (S100). . Completion of reset of motor control CPU 3 (after time t2) (S101), completion of initialization of motor control CPU 3 including software (after time t3) (S102), time allowance a1 in consideration of software initialization variation and the like. After taking the value, the counter 20 is reset (S103), and then the counter 30 is reset (S104). By this operation, the values of the counter 20 and the counter 30 become zero and coincide with each other. Subsequently, the reset of the counter 30 is released (S105), and the measurement by the A and B signals of the counter 30 is permitted. Thereafter, the reset of the counter 20 is released (S106). When the reset of the counter 20 is released, the counter 20 performs the initialization following operation, and the A and B signals are output according to the increase / decrease of the counter value φ of the counter 20, and the counter 30 operates during the initialization following operation of the counter 20. By measuring the generated A and B signals, all three values of the resolver rotation angle θ, the counter value φ, and the counter value ψ coincide with each other when the initialization of the counter 20 is completed. Since the initialization follow-up period c also changes depending on the initial value α of the resolver rotation angle θ, the time for determining that the counter value 一致 coincides with the counter value φ is determined by the reset release 82 of the counter 20 from the R / D conversion IC 2 After the elapse of a predetermined waiting time τ including a sufficient margin time a2 with respect to the maximum value c _max of the initialization follow-up period c of the counter 20 determined by the feedback gain of the feedback operation circuit.
[0014]
After the predetermined waiting time τ, according to the present invention, the counter value 得 obtained by counting the output A and B signals and the U and V output from the encoder IF 27 according to the increase and decrease of the counter value φ. , W signal, the difference Δψ from the angle ψ ′ exceeds a predetermined value, the diagnosis that the rotation angle detecting device determines that the rotation angle is abnormal is also performed. As shown in FIG. 4, the rotation angle can be estimated with a resolution of 60 ° by a combination of the U, V, and W signals. For example, when a combination of U / V / W = high level / low level / high level is detected, if the median value of the angle range to be taken by this combination is assumed to be the estimated rotation angle ψ ′, 求 め ′ = 30 ° is obtained. (S108). At this time, the counter value を 取 る should be in the range of 0 to 60 °, and the difference Δψ (= ψ−ψ ′) between the estimated rotation angle ψ ′ and the counter value ゜ becomes −30 ° to 30 °. The threshold value ψ _TH is calculated in consideration of some margin such as a resolution error, and if the threshold value exceeds the range of | Δψ | <ψ _TH (S109), the encoder I / F27 or A, B, Z, U, V, An abnormality due to a failure of any one of the W signal lines or the input / output port of the counter 30, the R / D conversion IC 2, or the motor control CPU 3, that is, an abnormality of the rotation angle detecting device can be determined. If there is no abnormality, the motor shifts to the normal control state, the motor is controlled based on the counter value の of the counter 30, rotates, and the resolver rotation angle θ changes from the initial value α.
[0015]
According to the first embodiment, the counter 20 and the counter 30 are reset immediately after the CPU power supply 5 is turned on or immediately after the CPU power supply 5 recovers from an instantaneous drop, and the reset is released in the order of the counter 30 and the counter 20. With a simple circuit configuration, the counter values φ and の of the counter 20 and the counter 30 can be matched without using a dedicated serial interface circuit. Further, after the counter value φ and the counter value 一致 coincide with each other, the encoder I / F 27 or A, B, and Z are compared by comparing the resolver rotation angle range that can be estimated from the state of the U, V, and W phase outputs with the counter value ψ. , U, V, or W signal line, or the failure of the counter 30, the R / D conversion IC 2, or the input / output port of the motor control CPU 3, etc., can be determined, and the reliability of the counter value ψ can be improved. It has become.
[0016]
Next, the second embodiment will be described with reference to FIGS. FIG. 5 is a circuit diagram showing the second embodiment. The configuration of the second embodiment will be described with reference to FIG. The description of the same configuration as in FIG. 1 is omitted. The power supply control circuit 35 (power supply control means, second reset means, and reset release means) turns on / off the power on / off circuit 6 for the R / D conversion IC 6 according to an instruction from the power on / sag detection means 33. / OFF 86 control and reset 83 and reset release 84 of the counter 30 are performed. The power supply on / off circuit 6 for the R / D conversion IC is controlled by the power supply control circuit 35 to turn on / off the power supply 4 for the R / D conversion IC (power supply for the R / D conversion means).
[0017]
FIG. 6 is a time chart showing the operation of the second embodiment, and FIG. 7 is a flowchart showing the operation of the motor control CPU 3 of the second embodiment. The operation of the second embodiment will be described with reference to FIGS. First, after the power supply 4 for the R / D conversion IC and the CPU power supply 5 are turned on (or the voltage of the CPU power supply 5 returns from a value lower than a predetermined value to a predetermined value or more), resetting and initialization of the motor control CPU 3 are started. Until the initialization of the CPU 3 is completed (S100 to S102), it is the same as the flowchart of FIG. After the initialization of the motor control CPU 3 including the software is completed (after the time t3) (S102), and after taking a time margin a1 in consideration of the initialization variation of the software (the stable state in which the motor control CPU 3 is set up). After resetting the counter 30 (S104), and then turning off the power supply 4 for the R / D conversion IC (S203), the reset of the counter 30 is released (S105), and outputs A and B from the R / D conversion IC 2 etc. Then, the power supply 4 for the R / D conversion IC is turned on (S206). When the power supply 4 for the R / D conversion IC is turned on, the counter 20 is reset by a power-on reset circuit 28 in the R / D conversion IC 2. After the power-on reset time b, the counter 20 performs the initialization following operation, and the A and B signals are output according to the increase or decrease of the counter value φ of the counter 20, and the counter 30 generates during the initialization following operation of the counter 20. By measuring the signals A and B, all three values of the resolver rotation angle θ, the counter value φ, and the counter value ψ coincide with each other when the initialization of the counter 20 is completed. Since the initialization follow-up period c also changes depending on the initial value α of the resolver rotation angle θ, the time when it is determined that the counter value 一致 coincides with the counter value φ is from the time when the power supply 4 for the R / D conversion IC is turned on to the power supply. A predetermined waiting time τ1 including a sufficient margin time a2 with respect to the ON reset time b and the maximum value c _max of the initialization follow-up period c of the counter 20 determined by the feedback gain of the feedback operation circuit of the R / D conversion IC2. After the passage of. The operation after determining whether or not the predetermined time period τ1 has elapsed in S207 is the same as that in the first embodiment described above.
[0018]
According to the second embodiment, the operation of turning off / on the R / D conversion IC power supply 4 immediately after turning on the CPU power supply 5 or immediately after the CPU power supply 5 recovers from an instantaneous drop, resetting and resetting the counter 30 With a simple configuration called reset release, the counter value φ and 一致 can be matched immediately after the CPU power supply 5 is turned on or immediately after the CPU power supply 5 recovers from a momentary drop. Further, after the counter value φ and the counter value 一致 coincide with each other, the encoder I / F 27 or A, B, and Z are compared by comparing the resolver rotation angle range that can be estimated from the state of the U, V, and W phase outputs with the counter value ψ. , U, V, or W signal line, or the failure of the counter 30, the R / D conversion IC 2, or the input / output port of the motor control CPU 3, etc., can be determined, and the reliability of the counter value ψ can be improved. It has become.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram showing a first embodiment.
FIG. 2 is a time chart showing the operation of the first embodiment.
FIG. 3 is a flowchart illustrating an operation of a motor control CPU 3 according to the first embodiment.
FIG. 4 is a time chart showing operations of U, V, and W phase outputs.
FIG. 5 is a circuit configuration diagram showing a second embodiment.
FIG. 6 is a time chart showing the operation of the second embodiment.
FIG. 7 is a flowchart illustrating an operation of a motor control CPU 3 according to the second embodiment.
[Explanation of symbols]
1. Resolver 2. R / D conversion IC
3: CPU for motor control
4 R / D conversion IC power supply 5 CPU power supply 20 UP / DOWN counter 27 Encoder signal I / F
28 power-on reset circuit 30 counter 31 comparative diagnostic means 32 rotation angle estimating means 33 power-on / voltage drop detecting means 34 reset sequence generating means 35 power control circuit

Claims (4)

A resolver that outputs a signal according to the rotation angle of the rotating machine,
R / D conversion means comprising a first counter for increasing or decreasing the count value so as to match the rotation angle, and outputting a signal corresponding to the increase or decrease of the first counter;
A rotation angle detection unit that includes a second counter that increases and decreases a count value based on a signal output from the R / D conversion unit, and that detects the rotation angle based on the count value of the second counter;
In a rotation angle detection device for a rotating machine having
Power supply state detection means for detecting that at least the power of the rotation angle detection means has been turned on, or that the voltage of the power supply has returned to a predetermined value or more from less than a predetermined value,
First reset means for resetting the first counter;
A second reset operation for resetting the second counter;
Reset canceling means for canceling reset processing of the first counter and the second counter, wherein the first reset means and the second reset means are turned on by the power state detecting means. Performed, or when it is detected that the voltage of the power supply has returned from the value less than the predetermined value to the value equal to or more than the predetermined value, performs reset processing of the first and second counters, and the reset canceling means includes: A rotation angle detection device, wherein reset processing is canceled in the order of the second counter and the first counter. The R / D conversion means includes three-phase signal output means for outputting U, V, and W phase signals based on the count value of the first counter, and the rotation angle detection means includes the U, V, and W phase signals. Rotation angle estimating means for estimating the rotation angle of the rotating machine at a resolution of 60 degrees based on the rotation angle, a detection angle of the rotation angle detection means a predetermined time after reset processing of the first counter is canceled, and 2. The rotation according to claim 1, further comprising an abnormality determination unit that compares the rotation angle estimated by the estimation unit and determines that the rotation angle detection device is abnormal when there is a difference equal to or more than a predetermined value. Angle detector. A resolver that outputs a signal according to the rotation angle of the rotating machine,
R / D conversion means comprising a first counter for increasing or decreasing the count value so as to match the rotation angle, and outputting a signal corresponding to the increase or decrease of the first counter;
A second counter for increasing or decreasing a count value based on a signal output from the R / D conversion means, and a rotation angle detection means for detecting the rotation angle based on the count value of the second counter. In the rotation angle detection device of the rotating machine provided with,
Power control means capable of turning on the power of the R / D conversion means;
Third reset means for resetting the first counter when the power of the R / D conversion means is turned on;
Power supply state detection means for detecting that at least the power of the rotation angle detection means has been turned on, or that the voltage of the power supply of the rotation angle detection means has returned from less than a predetermined value to a predetermined value or more,
When the power of the rotation angle detection unit is turned on or the voltage of the power supply of the rotation angle detection unit is returned from a value less than a predetermined value to a value equal to or more than a predetermined value by the power state detection unit, And a second reset unit for resetting the second counter. The power supply control unit is configured to reset the power of the R / D conversion unit after the second reset unit resets the second counter. And resetting the first counter by the third reset means. The R / D conversion means includes three-phase signal output means for outputting U, V, and W phase signals based on the count value of the first counter, and the rotation angle detection means includes the U, V, and W phase signals. A rotation angle estimating means for determining a rotation angle of the rotating machine at a resolution of 60 degrees based on the rotation angle of the rotating machine; It is characterized by comprising abnormality determination means for comparing the detected angle with the rotation angle estimated by the rotation angle estimation means, and determining that the rotation angle detection device is abnormal when there is a difference equal to or more than a predetermined value. The rotation angle detection device according to claim 3.

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