Dither current power supply control method and dither current power supply control apparatus

Patent metadata

Field	Value
Publication number	US-10079087-B2
Application number	US-201615041205-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Sep 2, 2015
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

In the dither current power supply control method, in order to prevent occurrence of a difference between the target average current and the detected average current, which is caused when a medium current (I 0 ) between a dither large current (I 2 ) and a dither small current (I 1 ) and a waveform average (Ia) of the dither current are different from each other depending on a response time difference (a−b) between a rise time (b) and a fall time (a) of the dither current, negative feedback control is carried out by using a command medium current corresponding to the target average current corrected by a correction parameter based on experimentally measured data, thereby suppressing occurrence of a transient fluctuation error by the negative feedback control, so that a highly precise and stable load current is acquired.

First claim

What is claimed is:

1. A dither current power supply control method, which comprises calculation control step for generating, for an inductive electric load for driving an actuator having a sliding resistance, a command signal for an instruction current corresponding to a target average current Iaa so that the target average current Iaa and a detected average current Idd match each other, to thereby carry out negative feedback control on an energization current,
the target average current Iaa being added with a predetermined dither amplitude current ΔI determined by the sliding resistance,
the dither current power supply control method comprising:
setting the dither amplitude current ΔI as a deviation value ΔI=I 2 −I 1 between a saturation estimated value I 2 of a dither large current in a dither current large period B within a dither amplitude cycle Td and a saturation estimated value I 1 of a dither small current in a dither current small period A (A=Td−B) within the dither amplitude cycle Td so that (Expression 1) is established when a dither medium current is expressed by I 0 =(I 2 +I 1 )/2,
I 2= I 0+Δ I/ 2, I 1= I 0−Δ I/ 2  (Expression 1);

calculating a waveform average current Ia by (Expression 2),
Ia=[I 2×( B−b )+ I 1×( A−a )+ I 0×( b+a )]/ Td=I 0+0.5×Δ I [( B−b )−( A−a )]/ Td   (Expression 2),

where b represents a rise time during which the energization current increases from the dither small current I 1 to the dither large current I 2 , and a represents a fall time during which the energization current decreases from the dither large current I 2 to the dither small current I 1 ,
the waveform average current Ia being a value acquired by dividing a time integral of the energization current during the dither amplitude cycle Td by the dither amplitude cycle Td,
the dither medium current I 0 being calculated so that the waveform average current Ia matches the target average current Iaa,
the dither medium current I 0 serving as the instruction current for acquiring the target average current Iaa;
energizing and driving, on an experimental stage, the inductive electric load, which is a sample, with the dither large current I 2 and the dither small current I 1 in the dither amplitude cycle Td, and acquiring, through a measurement or a simulation on a computer, experimentally measured data of a response time difference (a−b) between the rise time b and the fall time a corresponding to the dither medium current I 0 on a plurality of stages acquired in the energizing and driving;
storing, on a manufacturing/assembly stage, an approximation equation or a data table of “dither medium current I 0 to average response time difference ((a−b))” calculated based on an average of the experimentally measured data acquired with a plurality of samples as a correction parameter in a program memory configured to cooperate with a microprocessor serving as calculation control means for performing the calculation control step; and
reading and setting, as a first step of an actual operation stage, the given target average current Iaa and the dither amplitude current ΔI; calculating, as a second step, the instruction current that establishes such a relationship that the waveform average current Ia represented as Expression (2) matches the given target average current Iaa and a dither duty Γ=B/Td, which is a ratio of the dither current large period B to the dither amplitude cycle Td, and setting the instruction current as the dither medium current I 0 ; and carrying out, as a third step, negative feedback by the calculation control means so as to establish such a relationship that the detected average current Idd of the energization current and the target average current Iaa, namely, the waveform average current Ia, match each other.

2. The dither current power supply control method according to claim 1 ,
wherein the acquiring the experimentally measured data comprises, while adjusting the dither duty Γ=B/Td for the predetermined dither medium current I 0 with the dither amplitude cycle Td=A+B being set constant, measuring the dither current large period B or the dither current small period A at a time point when the detected average current Idd and the dither medium current I 0 match each other, the state in which the dither medium current I 0 and the detected average current Idd, namely, the waveform average current Ia, match each other meaning a state in which a difference value (B−b) between the dither current large period B and the rise time b in (Expression 2) and a difference value (A−a) between the dither current small period A and the fall time a are equal to each other, and the dither medium current I 0 and the waveform average current Ia match each other, and (Expression 3a) and (Expression 3b) are established,
A =[( Td +( a−b )]/2  (Expression 3a)

B =[( Td −( a−b )]/2  (Expression 3b), and

wherein the correction parameter comprises the approximation equation or the data table of “dither medium current I 0 to average response time difference ((a−b))” acquired by carrying out, in an environment at a reference voltage and a reference temperature, experimental measurement on a plurality of samples of the inductive electric load based on the predetermined dither amplitude cycle Td, the dither amplitude current ΔI determined in correspondence to the target average current Iaa, and the dither medium current I 0 on the plurality of stages, calculating the response time difference (a−b) by (Expression 4) based on a dither current large period BOO and a dither current small period A 00 actually measured in correspondence to the experimental measurement, and setting an average of the plurality of samples as the average response time difference ((a−b)) for the dither medium current I 0 ,
( a−b )= Td− 2× B 00(=2× A 00− Td )→average(( a−b ))  (Expression 4).

3. The dither current power supply control method according to claim 2 ,
wherein, on the actual operation stage, one of a first correction method and a second correction method is applied,
wherein the first correction method comprises setting B=A in (Expression 2) so that the dither current large period B and the dither current small period A match each other, to thereby fix the dither duty Γ=B/Td to 50%, and a relationship between the waveform average current Ia serving as the target average current Iaa and the dither medium current I 0 serving as the instruction current in the first correction method is calculated by (Expression 2a),
Iaa=Ia=I 0+0.5×Δ I ×(( a−b ))  (Expression 2a),

wherein the second correction method comprises setting B−b=A−a in (Expression 2) so that the waveform average current Ia serving as the target average current Iaa and the dither medium current I 0 serving as the instruction current match each other, and, in correspondence to the dither medium current I 0 , the dither current large period B or the dither current small period A is calculated by (Expression 5b) or (Expression 5a), and
A =[( Td +(( a−b ))]/2  (Expression 5a)

B =[( Td −(( a−b ))]/2  (Expression 5b), and

wherein, as the average response time difference ((a−b)), an average response time difference corresponding to a medium value between a minimum value and a maximum value of a practical range of the target average current Iaa or corresponding to a specific representative target average current frequently used is applied, or an average response time difference calculated by interpolation by using a plurality of average response time differences relating to the target average current Iaa on the plurality of stages is applied.

4. The dither current power supply control method according to claim 2 ,
wherein, on the actual operation stage, both a first correction method and a third correction method are applied,
wherein the first corr

Assignees

• Mitsubishi Electric Corp

Inventors

• Matsumoto Shuichi
• Nakanishi Masato
• Iguchi Shingo
• Arita Hiroyuki
• Ogata Tomoaki

Classifications

• H01F7/064 Primary

  Circuit arrangements for actuating electromagnets (circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325) · CPC title

• F02D41/1408

  Dithering techniques · CPC title

• H01F7/1844 Primary

  Monitoring or fail-safe circuits (for relays H01H47/002) · CPC title

• H01F2007/1866

  with regulation loop · CPC title

• H02M7/21 Primary

  using devices of a triode or transistor type requiring continuous application of a control signal · CPC title