DE102009029527A1 - Switching arrangement for evaluation of phase signals of generator, has device for detecting amplitude of phase signals, where output of comparator is provided for evaluation of phase signals - Google Patents

Abstract

The switching arrangement has a device for detecting the amplitude of the phase signals. A comparator is provided for comparing the detected amplitude of the phase signals with a current value of the phase signal. An output of the comparator is provided for evaluation of the phase signals. An independent claim is also included for a method for evaluation of a phase signals of the generator.

Description

The invention relates to a circuit arrangement for evaluating at least one phase signal of a generator and to a method for evaluating at least one phase signal.

State of the art

Generators are usually used to generate electrical energy in motor vehicles. In particular, three-phase generators are used, the output voltage of which can be regulated to constant values by means of a voltage regulator by suitable influencing of the exciter current. The excitation current is provided via exciter diodes.

In the available generator regulators, the B + connection of the battery is connected directly to the controller. When the vehicle is at a standstill, the controller must therefore go into the standby state or standby with a reduced power consumption. The "wake-up" of the controller is usually initiated via a customer pin of the customer plug (L, LIN, PWM, BSS, etc.). When the customer plug falls off or the line is interrupted, an emergency start must be ensured by evaluating one or more phase signals from the generator.

Thus, for example, the evaluation of a phase for emergency start function / self-starting function via a dU / dt detection is known. When evaluating a phase for the emergency start / self-start, the phase voltage is converted via a differential element into a dynamic current, which is dependent on the slope of the phase voltage. This current is compared to a fixed current threshold. When this current threshold is exceeded, a switch-on signal is generated for the controller. With this switch-on signal, the emergency start of the generator controller takes place, this means that the generator controller is woken up from standby and switched on.

It should be noted that a full integration of this evaluation circuit in terms of their function by the economically feasible area of the capacitance and thus by both the maximum capacitance value and by effects on the chip, such as, leakage currents at high temperatures, limited. In addition to the useful signal further interference signals that may also lie in the useful range. A suitable bandpass filtering is necessary, but in this solution again associated with area overhead.

Furthermore, a controller is known in which takes place by subtraction an evaluation of two phase voltages.

From the publication DE 197 32 961 A1 is a controller with phase voltage evaluation for a three-phase generator known. The three-phase generator comprises phase windings and a field winding. There are provided means for detecting and evaluating at least one phase voltage and means for taking into account the detected phase voltage in the control of the exciter current flowing through the exciter winding. The phase voltage is evaluated by means of a window comparator with variable thresholds. Via a VCL signal, which switches in each case when a threshold adaptation takes place, a frequency-dependent signal can be generated, which can be evaluated as a measure of the generator speed.

Since in the newer generators partially rectifier diodes or high efficiency diodes with strong non-linear characteristic with respect to the reverse currents at high temperatures are installed, these diodes, the DC quiescent level at the phase terminals in the generator standstill in the range of 0 V up to B + voltage. These sometimes very high leakage currents reduce the phase amplitude at startup, which requires sensitive amplitude (AC) detection.

Disclosure of the invention

A circuit arrangement according to claim 1 and a method according to claim 7 are presented. Embodiments of the circuit arrangement and the method emerge from the dependent claims.

• – geringe Chipfläche
• – einfache Konstruktion (nur ein Anschluss am Regler für die Phasenauswertung)
• – Auswertung von sehr kleinen AC-Signalen (< 0,5 V)
• – großer DC-Bereich (0 V bis U_B+)
• – Temperaturbereich (–40°C bis 175°C)

The voltage regulator according to the invention for a generator, in particular an alternator, takes into account the above-mentioned new requirements for a circuit for an emergency start. The presented solution enables a fully integrated solution on-chip. For this are necessary:

• - small chip area
• - simple construction (only one connection at the controller for the phase evaluation)
• - Evaluation of very small AC signals (<0.5 V)
• - large DC range (0 V to U_B +)
• - Temperature range (-40 ° C to 175 ° C)

Since the evaluation is usually realized for only a single phase connection for reasons of design and cost reasons, the described circuit is suitable for detecting and evaluating only a single phase connection. The AC evaluation must be possible at very low AC amplitudes to less than 0.5 V _SS and simultaneously superimposed DC voltage level from 0 V to B +. The circuit described is suitable for all available generators for a safe AC Evaluation suitable and thus allows for these a safe emergency start.

With the presented circuit arrangement and the method described, the DC evaluation range is significantly increased in the "emergency start" compared to known solutions. It is also possible to detect lower amplitudes that can be precisely set. A significant advantage is also the lower space requirement compared to known solutions, so that a full integration on-chip is economically feasible.

In one possible embodiment, the circuit arrangement comprises an input divider with low-pass filter and adjustable corner frequency for an analog pre-filtering, a circuit for detecting the amplitude of the phase signal by means of a "sample and hold" method and an adjustable offset comparator for comparing the stored phase voltage with the instantaneous value , This results in the recognition of the AC component. The offset of the comparator sets the sensitivity, i. H. the AC threshold, fixed. Furthermore, an oscillator for controlling the different states, an evaluation unit or logic with plausibility monitoring, an intelligent evaluation with simultaneous quiescent current reduction and a secure function by locking during operation (no self-holding in case of failure) can be used.

The described circuit arrangement can be realized within an evaluation in an active rectifier or in a starter-generator electronics and thus in any generator electronics installed in the generator or adapted as a pathway solution. In the evaluation of more than one phase connection, this control and filtering is applicable to each of the phase terminals. In addition, the circuit arrangement can also be used in 28 V systems in commercial vehicles.

In principle, use is possible with a generator with active rectifier and in starter-generator systems.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 shows an example of phase signals during an emergency start phase / self-starting phase

2 shows a circuit arrangement for phase evaluation according to the prior art.

3 shows a first embodiment of the presented circuit arrangement.

4 shows a second embodiment of the presented circuit arrangement.

5 shows waveforms in the circuit arrangement 3 ,

6 shows a generator-controller system.

Embodiments of the invention

The invention is schematically illustrated by means of embodiments in the drawings and will be described in detail below with reference to the drawings.

In 1 Examples of phase signals during an emergency start phase / self-starting phase are shown. In the illustration is on an abscissa 10 the time and at an ordinate 12 the tension applied. A dashed line 14 indicates the battery voltage U _{B +} . It is a first waveform 16 , a second waveform 18 and a third waveform 20 played. It can be seen that with the signals 16 . 18 and 20 a DC component of an AC component, the AC useful signal, superimposed. double arrow 22 indicates a measure of U _S (peak-to-peak value) for this AC component less than 0.5 V _SS .

2 shows a circuit arrangement for phase evaluation according to the prior art, the whole with the reference numeral 30 is designated. In this one at a terminal V 32 adjacent phase evaluated according to the dU / dt method. The illustration also shows a resistance 34 , a capacitor 36 , a power source 38 and a comparator 40 , at one of its terminals 42 a reference voltage is applied, which is connected to the other terminal 44 applied voltage is compared. At an exit 46 of the comparator 40 a so-called wake-up signal can be output.

In 3 is a first embodiment of the described circuit arrangement, in total with the reference numeral 60 is indicated, shown. The illustration shows a terminal V 62 at which the phase or phase voltage is present, a switch 64 for sampling and holding (sample / hold switch), a capacitor 66 for storing the phase voltage, a comparator 68 , an evaluation unit 70 to evaluate an output 72 of the comparator 68 , an offset encoder 74 for example, which gives an offset value of 0.5 V, a timing unit 76 to operate the switch 64 and for determining an evaluation window and an oscillator 78 , The comparator 68 is thus formed with adjustable offset. An exit 82 the evaluation unit 70 represents the wakeup signal to turn on the regulator.

With the oscillator 78 becomes an alternating signal 80 generated, with which the time control unit 76 is driven, in turn, according to the signal 80 the switch 64 operated alternately, so that in certain periods of time at the terminal 62 applied phase voltage is passed through and the capacitor 66 charging (sample phase). In the second phase is the switch 64 open. This turns the voltage on the capacitor 66 stored or held (hold phase). This process is repeated periodically. The charged size at the capacitor 66 is during the hold phase using the comparator 68 is compared with the instantaneous value of the phase signal to which an offset of, for example, 0.5 V is applied. In the switching point of the comparator 68 corresponds to the fixed offset, which simultaneously represents the AC threshold, the AC component of the phase voltage. With the time control unit 76 is at fixed times the output signal 72 of the comparator 68 with the help of the evaluation unit 70 evaluated. If the specified switch-on conditions are fulfilled, a wake-up signal is output 82 is output and the controller is switched on.

In 4 is another embodiment of the proposed circuit arrangement, in total with the reference numeral 100 designated, shown. The illustration shows a terminal V 102 , a switch 104 , a capacitor 106 , a first comparator 108 and a second comparator 109 , an evaluation unit 110 , a first offset encoder 114 (eg, 0.25V) and a second offset encoder 115 (e.g., -0.25V), a timing controller 116 and an oscillator 118 , The comparators 108 and 109 are therefore designed with adjustable offset. An exit 120 represents the wakeup signal.

At the in 4 illustrated circuit arrangement 100 is advantageous that the switching can also be done by means of an evaluation of the phase voltage direction. Switching on only when the upper threshold is exceeded and then below the lower threshold requires an alternating signal at the phase connection or pin. Voltage changes on the phase, which are caused for example by leakage currents in the rectifier diodes, can be filtered out and a switch-on in this case can be suppressed.

5 shows waveforms in the embodiment according to 3 , In this case, in the illustration, a drive signal 200 according to the alternating signal 80 of the oscillator 78 for controlling the time control unit 76 to operate the switch 64 shown. With the switch closed 64 (periods 202 ), a sample is sampled. When the switch is open 64 (periods 204 ) is a hold. Below is a signal 210 represented by the time control unit 76 to the evaluation unit 70 is given. To recognize are periods 212 (Evaluation window) in which an evaluation is active. In these periods 212 if the evaluation is active, this depends on the time periods 204 in which the switch 64 is open.

Furthermore, the presentation shows the course 220 the phase voltage at the terminal 62 (Detail shows rising edge of the AC signal). This course is again shown dashed in comparison to another waveform 230 that has the voltage on the capacitor 66 reproduces. The comparison between the course 220 the phase voltage and the waveform 230 on the capacitor 66 is with the comparator 68 carried out. If a certain offset voltage, in this case 0.5 V exceeded, what with arrows 240 is displayed, a so-called wake-up signal 250 ( 3 , Signal 82 ) from the evaluation unit 70 be issued.

6 shows a generator-controller system 300 with a regulator unit 302 and a generator unit 306 , a control unit 308 and a wiring system 310 , A generator 304 is via a rectifier circuit 312 at a B + connection 314 and a B port 316 with the electrical system 310 connected.

The signal lines 318 and 320 lead to the control unit 308 and may be for diagnosis and / or control of the regulator unit 302 be used. Furthermore, a phase connection 322 at the rectifier 312 tapped and the controller unit 302 fed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19732961 A1 [0007]

Claims (10)

Circuit arrangement for evaluating at least one phase signal of a generator ( 304 ), means for detecting the amplitude of the phase signal and a first comparator ( 68 . 108 ) for comparing the detected amplitude of the phase signal with an instantaneous value of the phase signal, wherein an output ( 72 . 122 ) of the first comparator ( 68 . 108 ) is provided for evaluating the phase signal. Circuit arrangement according to Claim 1, in which the means for detecting the amplitude of the phase signal comprise a switch ( 64 . 104 ) and a capacitor ( 66 . 106 ) and designed to carry out a "sample and hold" method. Circuit arrangement according to Claim 2, in which an oscillator ( 78 . 118 ) is provided for controlling the switch. Circuit arrangement according to one of Claims 1 to 3, in which a second comparator ( 109 ) whose output ( 123 ) is also provided for evaluation of the phase signal. Circuit arrangement according to one of Claims 1 to 4, in which the first comparator ( 68 . 108 ) or the first and the second comparator ( 68 . 108 . 109 ) as a comparator ( 68 . 108 . 109 ) is formed with adjustable offset or are. Circuit arrangement according to one of claims 1 to 3, wherein additionally an input divider is provided with low-pass filter. Method for evaluating at least one phase signal of a generator ( 304 ), in which a means for detecting the amplitude of the phase signal detects an amplitude of the phase signal, with a first comparator ( 68 . 108 ) compared the detected amplitude of the phase signal with an instantaneous value and an output ( 72 . 122 ) of the comparator is used to evaluate the phase signal. Method according to Claim 7, in which the amplitude of the phase signal is connected to a switch ( 64 . 104 ) and a capacitor ( 66 . 106 ) is performed with a "sample and hold" method. Method according to Claim 8, in which the switch ( 64 . 104 ) with an oscillator ( 78 . 118 ) is driven. Method according to one of Claims 7 to 9, in which a second comparator ( 109 ) is used.

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