Pulse driver circuit

Abstract

The disclosed pulse driver circuit comprises a DC voltage generation circuit that generates a DC voltage according to a selected inductor current command or a double-terminated inductor voltage command, a smoothing inductor, a current pulse generation circuit that generates a current pulse from an inductor current smoothed by the smoothing inductor, an inductor current control circuit that issues an inductor current command based on an error in the inductor current relative to a target inductor current value, and a double-terminated inductor voltage control circuit that issues a double-terminated inductor voltage command based on an error in a voltage derived from a double-terminated inductor voltage detected by a double-terminated inductor voltage sensor relative to a target double-terminated inductor voltage of 0 V or a predetermined voltage close to 0 V, and a command selection circuit 10.which selects a choke current command or a two-terminated choke voltage command according to the on / off state of a current pulse.

Description

[0001] The present invention relates to a pulse driver circuit.

[0002] Laser processing machines are known that perform operations such as cutting and marking metal using a laser diode (LD). Such a laser processing machine requires a high drive current and a laser pulse with a short pulse width, depending on the processing conditions. A laser diode is a current-controlled element and therefore uses a constant-current power supply circuit capable of providing the constant current required for laser oscillation at the desired power. Such a constant-current power supply circuit utilizes a power supply system with high switching efficiency and therefore generally employs a smoothing choke.Although an attempt is made to output a current pulse with a short pulse width according to the processing conditions, the response rate of the output current is therefore slow, and a square wave is not achieved.

[0003] A laser processing machine used in this way is therefore equipped with a pulse driver circuit. In the pulse driver circuit, a switching element is connected in parallel to a laser diode. When the switching element is turned on and off, the current path of an output current from a constant current source is switched between a supply path to the laser diode and a feedback path to the constant current source, thus delivering a required square-wave current pulse with a high-speed current response to the laser diode (see, for example, WO 2016 / 167019 (in particular the Fig. 5 and the second embodiment)).

[0004] However, with the conventional pulse driver circuit, the problem is that increasing the pulse width of the current pulse increases the ripple of the current pulse and distorts the waveform.

[0005] The object of the present invention is to create a pulse driver circuit with improved characteristics.

[0006] This problem is solved by a pulse driver circuit according to claim 1.

[0007] To solve the above problem, a pulse driver circuit according to one aspect of the present disclosure has the following features: a DC voltage generation circuit that generates and outputs a DC voltage according to an inductor current command or a double-ended inductor voltage command selected by a command selection circuit; a smoothing inductor having one end connected to a high-potential output end of the DC voltage generation circuit and smoothing an inductor current output by the DC voltage generation circuit; an output end having a first output end and a second output end, the second output end being connected to another end of the smoothing inductor, the first output end being connected to a low-potential output end of the DC voltage generation circuit, and a load driven by a current pulse being connected between the second output end and the first output end;A current pulse generation circuit that receives a pulse signal, alternately receiving a current pulse-off period and a current pulse-on period from an external source, short-circuits between the second output end and the first output end during the current pulse-off period and opens between the second output end and the first output end during the current pulse-on period to generate the current pulse from the inductor current smoothed by the smoothing inductor, and outputs the current pulse to the load via the output end; an inductor current sensor that detects the inductor current; an inductor current control circuit that issues an inductor current command based on an error of the inductor current detected by the inductor current sensor with respect to an inductor current target value; a two-terminal inductor voltage sensor that detects a two-terminal inductor voltage of the smoothing inductor;a two-terminated inductor voltage control circuit that issues a two-terminated inductor voltage command based on an error in a voltage derived from the two-terminated inductor voltage, which is detected by the two-terminated inductor voltage sensor, with reference to a voltage of 0 V as the target value of the two-terminal inductor voltage or a predetermined voltage close to 0 V; and the command selection circuit that receives the pulse signal from outside, selects and issues the inductor current command during the current pulse-on period and selects and issues the two-terminated inductor voltage command during the current pulse-off period.

[0008] The present disclosure has the effect of providing a pulse driver circuit with which the ripple of the current pulse can be improved.

[0009] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a block diagram illustrating an example of a pulse driver circuit design according to an embodiment of the present disclosure; Fig. 2 a circuit diagram that shows an example of a specific circuit configuration of the DC-DC converter circuit Fig. 1 represents; Fig. 3 a circuit diagram that shows an example of a specific circuit configuration of a main part of the pulse driver circuit Fig. 1 represents; Fig. 4 a circuit diagram that shows an example of a specific circuit configuration of a control system of the pulse driver circuit from Fig. 1 represents; Fig. 5 waveform diagrams of results from an operational simulation of a pulse driver circuit that only performs feedback control of an inductor current on a DC-DC converter circuit in the case of a current pulse having a frequency of 1 kHz; Fig.6 waveform diagrams of results from an operational simulation of a pulse driver circuit that only performs feedback control of an inductor current on a DC-DC converter circuit in the case of a current pulse having a frequency of 10 kHz; Fig. 7 Waveform diagrams of the results of an operating simulation of a pulse driver circuit that only performs feedback control of an inductor current on a DC-DC converter circuit in the case of a current pulse having a frequency of 50 kHz; Fig. 8 Waveform diagrams of the results of an operational simulation of a pulse driver circuit that performs feedback control of a two-terminal inductor voltage during a current pulse off period and feedback control of an inductor current during a current pulse on period on a DC-DC converter circuit in the case of a current pulse having a frequency of 1 kHz; and Fig.9 Waveform diagrams of results of an operating simulation of a pulse driver circuit that performs feedback control of a two-ended inductor voltage during a current pulse off period and feedback control of an inductor current during a current pulse on period on a DC voltage converter circuit in the case of a current pulse having a frequency of 10 kHz.

[0010] A pulse driver circuit according to one aspect of the present disclosure has the following features: a DC voltage generation circuit that generates and outputs a DC voltage according to an inductor current command or a double-ended inductor voltage command selected by a command selection circuit; a smoothing inductor having one end connected to a high-potential output end of the DC voltage generation circuit and smoothing an inductor current output by the DC voltage generation circuit; an output end having a first output end and a second output end, the second output end being connected to another end of the smoothing inductor.the first output end is connected to a low-potential output end of the DC voltage generation circuit, and a load driven by a current pulse is connected between the second output end and the first output end; a current pulse generation circuit that receives a pulse signal, alternately receiving a current pulse-off period and a current pulse-on period from an external source, short-circuits between the second output end and the first output end during the current pulse-off period and opens between the second output end and the first output end during the current pulse-on period to generate the current pulse from the inductor current, which is smoothed by the smoothing inductor, and outputs the current pulse to the load via the output end; an inductor current sensor that detects the inductor current; an inductor current control circuit,which issues a choke current command based on an error in the choke current detected by the choke current sensor with respect to a choke current target value; a two-terminal choke voltage sensor that detects a two-terminal choke voltage of the smoothing choke; a two-terminal choke voltage control circuit that issues a two-terminal choke voltage command based on an error in a voltage derived from the two-terminal choke voltage detected by the two-terminal choke voltage sensor with respect to a voltage of 0 V as the target value of the two-terminal choke voltage or a predetermined voltage close to 0 V; and the command selection circuit that receives the pulse signal from outside,During the current pulse-on period, the inductor current command is selected and output, and during the current pulse-off period, the two-terminal inductor voltage command is selected and output. The technical meaning of the expression "a voltage of 0 V or a predetermined voltage close to 0 V" is described here. An ideal target value of the two-terminal inductor voltage in the feedback control of the two-terminal inductor voltage is 0 V if the resistance component of the smoothing inductor is 0 Ω (for example, if the smoothing inductor is in a superconducting state). If the resistance component of the smoothing inductor is not 0 Ω, the ideal target value is a voltage...which corresponds to a voltage drop due to the resistance component of the smoothing choke (hereinafter referred to as the resistance drop voltage). In reality, however, the target value of the two-terminal choke voltage cannot be set to the ideal voltage value, since the resistance drop voltage depends on the magnitude of the choke current, and the target value of the two-terminal choke voltage is set to a suboptimal voltage value. The target value of the two-terminal choke voltage is therefore set to 0 V or a suboptimal voltage value, taking into account the resistance component of the smoothing choke and the range of variation of the choke current. This voltage value of 0 V or a suboptimal voltage value is "a voltage of 0 V or a predetermined voltage close to 0 V". Since the target value of the two-terminal choke voltage deviates from the ideal voltage value,During a rapid decrease in the load on the constant current source (DC voltage generation circuit + smoothing inductor), the feedback control is less effective at matching the energy output from the DC voltage generation circuit to the energy consumed by the load (here, the internal resistance of the constant current source). A voltage of 0 V or a predetermined voltage close to 0 V is determined by design, experimentation, simulation, or similar methods.

[0011] In the above setup, feedback control of the inductor current is performed on the DC voltage generation circuit during the current pulse on period. During the current pulse off period, feedback control of the inductor voltage at both ends is performed.

[0012] Initially, during the transition from the current pulse on period to the current pulse off period in the feedback control, when the current pulse is switched off, the load voltage of the constant current source assumes a value of 0 V. This is because the current pulse generation circuit short-circuits between the second and first outputs, and the first output is connected to the low-potential output of the DC-DC converter circuit. Consequently, the voltage output from the DC-DC converter is applied to the smoothing inductor at the output on the DC-DC converter side, and the potential on the load side assumes a value of 0 V.In the feedback control of the inductor voltage, the target value is 0 V or a predetermined voltage close to 0 V. Therefore, in the DC voltage generation circuit, the feedback control reduces the output voltage to 0 V or a predetermined voltage close to 0 V, so that the inductor voltage reaches a value of 0 V or a predetermined voltage close to 0 V. During this process, the DC voltage generation circuit is controlled in such a way that the existing inductor current is essentially maintained. This is because a change in the inductor current would cause the induced voltage to create a potential difference at both ends of the smoothing inductor.Thus, in the DC voltage generation circuit, the output voltage is feedback-controlled to a voltage of essentially 0 V, a voltage required to keep the inductor current essentially at its current value (the target inductor current value in feedback control). As a result, the energy output from the DC voltage generation circuit quickly matches the energy consumed by the load (here, by the internal resistance of the constant current source).

[0013] In the event of a transition from the current pulse off period to the current pulse on period during feedback control, when the current pulse is switched on to adjust the load voltage to a predetermined voltage (for example, 120 V), the inductor current output by the DC voltage generation circuit increases rapidly. If feedback control of the inductor current at the DC voltage generation circuit is performed during the current pulse off period, the inductor current output by the DC voltage generation circuit will be higher than the target inductor current value at the end of the current pulse off period.At the time of a transition to the current pulse-on period, the DC voltage generation circuit is feedback-controlled to reduce the inductor current until the inductor current output by the DC voltage generation circuit becomes lower than the inductor current target value, and therefore it is not possible to feedback-control the DC voltage generation circuit in such a way that the inductor current immediately assumes the inductor current target value.In contrast, the above configuration uses feedback control of the inductor voltage at both ends of the DC voltage generation circuit during the current pulse off period. This control essentially steers the inductor current to the target value, so that the inductor current detected by the inductor current sensor decreases significantly from the target value at the moment of transition to the current pulse on period. Consequently, the DC voltage generation circuit is directly controlled by feedback, ensuring the inductor current reaches the target value. As a result, the energy output from the DC voltage generation circuit quickly adjusts to the energy consumed by the load.As described above, the energy output from the DC voltage generation circuit rapidly adjusts to the energy consumed by the load (the internal resistance of the constant current source or the load driven by the current pulse) during the current pulse off and on periods. Consequently, the effect of the smoothing choke is suppressed to fundamentally improve the current pulse ripple.

[0014] The voltage of 0 V, or a predetermined voltage close to 0 V, can be a voltage in the range of 5% of the set output voltage of the DC voltage generation circuit. The absolute value of the terminal inductor voltage can be equal to or higher than the set output voltage of the DC voltage generation circuit at the moment when the load of the constant current source rapidly decreases. Therefore, a voltage close to 0 V, representing 5% of the set output voltage of the DC voltage generation circuit, can be considered the target value of the terminal inductor voltage in feedback control.

[0015] According to this training, the feedback control of the inductor voltage at both ends can, at the time of a rapid decrease in the load of the constant current source, appropriately adjust the energy output from the DC voltage generation circuit to the energy consumed by the load (here by the internal resistance of the constant current source).

[0016] The DC voltage generation circuit can be a DC voltage converter circuit that generates and outputs a square wave DC voltage, the square wave DC voltage being controlled by pulse width modulation (PWM) control, from a DC voltage input from a DC power supply using one or more switching elements that are switched on and off according to one or more PWM signals; the smoothing choke can be a choke with one end connected to a high-potential output end of the DC voltage converter circuit and configured to smooth the choke current output by the DC voltage converter circuit; the first output end of the output can be connected to a low-potential output end of the DC voltage converter circuit; the current pulse generation circuit can receive the pulse signal from a control device.The inductor current control circuit can receive the inductor current target value from the control device, and the command selection circuit can receive the pulse signal from the control device, and the pulse driver circuit can include a PWM signal generation circuit that generates one or more PWM signals according to the one or more switching elements according to the inductor current command or the double-ended inductor voltage command from the command selection circuit and outputs one or more PWM signals to the one or more switching elements.

[0017] According to this design, the DC-DC converter circuit generates a square-wave DC voltage controlled by PWM using one or more switching elements that are switched on and off according to one or more PWM signals generated by the inductor current command or the two-terminal inductor voltage command. The DC voltage can therefore be efficiently generated according to the inductor current command or the two-terminal inductor voltage command.

[0018] The pulse driver circuit can further include a two-terminal voltage averaging circuit that generates and outputs a voltage derived from a two-terminal voltage of the smoothing inductor, detected by the two-terminal inductor voltage sensor. This voltage is obtained by averaging the two-terminal voltages of the smoothing inductor. The two-terminal inductor voltage control circuit can be a circuit that issues the two-terminal inductor voltage command based on an error in the voltage output from the two-terminal voltage averaging circuit relative to the target value of the two-terminal voltage. According to this configuration, a correct two-terminal inductor voltage command can be issued.

[0019] In the following, certain embodiments of the present disclosure are described with reference to the drawings. In the following description, identical or corresponding elements in all drawings are designated by the same reference numerals, and redundant descriptions of the elements are omitted. The drawings described below serve to describe the present disclosure, and therefore an element not related to the present disclosure may be omitted in the drawings, a dimension may be incorrectly exaggerated, or the like, simplifications may be made, or the forms of corresponding elements may differ from one another in several drawings. In the specification and the claims, the state in which an electrical circuit is electrically connected may be described in a simplified way by stating that the electrical circuit is "connected".The present disclosure is not limited to the following embodiments.

[0020] As an exemplary embodiment of the present disclosure, an embodiment is presented in which the DC voltage generation circuit comprises a DC voltage converter circuit. In the present embodiment, a pulse driver circuit receives a pulse signal and a target inductor current value from a control device outside the pulse driver circuit.

[0021] Fig. Figure 1 is a block diagram illustrating an example of a pulse driver circuit according to an embodiment of the present disclosure. With reference to Fig.1 comprises a pulse driver circuit 100 as its main component, a DC-DC converter circuit 1 as an example of a DC-DC generation circuit, a smoothing inductor 2, an output end 3, and a current pulse generation circuit 4. The pulse driver circuit 100 further comprises, as a control system, an inductor current sensor 5, an inductor current control circuit 6, a two-terminal inductor voltage sensor 7, a two-terminal voltage averaging circuit 8, a two-terminal inductor voltage control circuit 9, a command selection circuit 10, and a PWM signal generation circuit 11.

[0022] These elements are described in detail below. DC / DC converter circuit 1

[0023] The DC-DC converter circuit 1 has a pair of input ends 1c and 1d that receive a DC voltage from a DC power supply 31. The DC-DC converter circuit 1 generates a square-wave DC voltage from the DC voltage, controlled by PWM, using one or more switching elements that are switched on and off according to one or more PWM signals Spwm, and outputs the square-wave DC voltage from a pair of a low-potential output end 1a and a high-potential output end 1b. The DC-DC converter circuit 1 only needs to be capable of generating a square-wave DC voltage controlled by PWM. Examples of the DC-DC converter circuit 1 include a combination of a full-bridge or half-bridge inverter and a rectifier circuit, and a voltage-reducing chopper.There is no particular restriction on the DC power supply 31, as long as it can output a DC voltage.

[0024] Fig. Figure 2 is a circuit diagram that shows an example of a specific circuit configuration of the DC-DC converter circuit 1. Fig. 1 represents. With reference to Fig. The DC-DC converter circuit 1 comprises a full-bridge inverter 41, a transformer 42, and a pair of rectifier elements 43, forming a two-phase half-wave rectifier circuit. This configuration is known and will therefore only be briefly described. The inverter 41 has a pair of input terminals 1c and 1d, which receive a DC voltage from the DC power supply 31. Fig.1. Four switching elements Q1 to Q4 receive four PWM signals Spwm. According to the PWM signals Spwm, a set of switching elements Q1 and Q2 and a set of switching elements Q3 and Q4 are alternately switched on to generate a square-wave AC voltage with a pulse width corresponding to the PWM signals Spwm, and the AC voltage is fed into a primary winding of the transformer 42. A secondary winding of the transformer 42 is provided with an intermediate tap, the intermediate tap is connected to the low-potential output end 1a of the DC-DC converter circuit 1, both ends of the secondary winding are connected to the anodes of diode D1 and diode D2 respectively, which form the pair of rectifier elements 43, and the cathodes of the pair consisting of diode D1 and diode D2 are connected to the high-potential output end 1b of the DC-DC converter circuit 1.The square-wave AC voltage input into the primary winding of transformer 42 is thus transformed according to the turns ratio and output as a two-phase square-wave AC voltage between the respective end of the secondary winding and the intermediate tap. The two-phase square-wave AC voltage is rectified by each of the diodes D1 and D2 in the pair, and rectified square-wave full-wave DC voltages with a pulse width corresponding to the PWM signals Spwm are output from the low-potential output 1a and the high-potential output 1b of the DC-DC converter circuit 1.

[0025] Fig. 3 is a circuit diagram that shows an example of a specific circuit configuration of the main part of the pulse driver circuit. Fig. 1 represents. With reference to Fig.Figure 3 shows the DC-DC converter circuit 1 comprising a switching element Q5 and a freewheeling diode D3 as a further example of the specific circuit configuration. The switching element Q5 has a high-potential main terminal (here, a collector of an insulated-gate bipolar transistor (IGBT)) connected to a high-potential output of a constant voltage source 51, and a low-potential main terminal (here, an emitter of the IGBT) connected to the smoothing inductor 2. The switching element Q5 has a control terminal (here, a gate of the IGBT) that receives a PWM signal Spwm. The freewheeling diode D3 has a cathode connected to the low-potential main terminal of the switching element Q5 and an anode connected to a low-potential output of the constant voltage source 51.The anode of the freewheeling diode D3 therefore corresponds to the low-potential output end 1a of the DC-DC converter circuit 1, and the cathode of the freewheeling diode D3 corresponds to the high-potential output end 1b of the DC-DC converter circuit 1.

[0026] The constant voltage source 51 is connected to the DC power supply 31. Fig. 1 similar and only needs to be capable of outputting a DC voltage.

[0027] The switching element Q5, for example, contains a transistor such as a field-effect transistor (FET), a bipolar transistor, or an IGBT. In this case, the switching element Q5 contains an IGBT.

[0028] Switching element Q5, freewheeling diode D3, and smoothing inductor 2 form a voltage-reducing chopper. Switching element Q5 is switched on and off according to the PWM signal Spwm input to the control terminal. Thus, switching element Q5 generates a square-wave DC voltage with a pulse width corresponding to the PWM signal Spwm from the DC voltage input from constant voltage source 51 and outputs this square-wave DC voltage to smoothing inductor 2. Smoothing inductor 2 generates a voltage corresponding to the on / off state of switching element Q5. During the on-period of switching element Q5, constant voltage source 51 supplies a current to the load side. During the off-period of switching element Q5, smoothing inductor 2 supplies a current to the load side, causing the current to flow through freewheeling diode D3. Smoothing choke 2

[0029] With reference to Fig.1 The smoothing choke 2 has one end that is connected to the high-potential output end 1b of the DC-DC converter circuit 1, and the other end is connected to a second output end 3b. With reference to Fig. In an example of a specific circuit configuration of the main part of the pulse driver circuit 100, the smoothing choke 2 has one end connected to the low-potential main terminal of the switching element Q5, and the other end is connected to the second output end 3b.

[0030] As part of the constant current source, the smoothing choke 2 serves to smooth a fluctuation caused by the PWM signal Spwm of the choke current output by the DC-DC converter circuit 1 (hereinafter sometimes simply referred to as the "choke current"), and to smooth a fluctuation caused by the current pulse generation of the choke current.

[0031] The smoothing choke 2 has a high inductance value; however, a smoothing choke 2 with a higher inductance value is larger, and therefore the size of the inductance value of the smoothing choke 2 is limited by the installation space available for the smoothing choke 2 in the device to which the pulse driver circuit 100 is attached. Therefore, a suitable value is selected for the inductance value of the smoothing choke 2, taking into account the installation space available for the smoothing choke 2 in the device to which the pulse driver circuit 100 is attached. In this case, the carrier frequency of the PWM signal Spwm is much higher than the pulse frequency of the current pulse (the frequency of the pulse signal), and therefore the fluctuation caused by the PWM signal Spwm in the choke current is sufficiently smoothed. End of exit 3

[0032] With reference to Fig. 2 and Fig.The output end 3 comprises a first output end 3a and a second output end 3b. The first output end 3a is a low-potential output end and is grounded in one example of a specific circuit configuration of the main part of the pulse driver circuit 100. The second output end 3b is a high-potential output end. A load 32 is connected between the first output end 3a and the second output end 3b.

[0033] Load 32 is a load driven by a current pulse. Load 32 is, for example, a laser diode or a light-emitting diode, etc. Current pulse generation circuit 4

[0034] With reference to Fig. The current pulse generation circuit 4 is connected between the first output end 3a and the second output end 3b. The current pulse generation circuit 4 receives a pulse signal Spls from a control device 33.

[0035] The control device 33, for example, is a device that controls a machine tool during machining operations using a load element 32. The control device 33 comprises a processor Pr and a memory Me. That is, the control device 33 comprises a hardware control circuit arrangement including the processor Pr and the memory Me. A machining program is stored in the memory Me, and the processor Pr reads the machining program from the memory Me and executes the machining program. As a result, the control device 33 operates as follows: The control device 33 controls the machine tool according to the machining program and, as part of the control, outputs the pulse signal Spls to the pulse driver circuit 100. The control device 33 outputs a throttle current target value Ilset to the pulse driver circuit 100, as described below.The pulse signal Spls, for example, is a binary signal that alternately comprises: a low-level section representing a current pulse-on period in which a current pulse is output (the current pulse is on), and a high-level section representing a current pulse-off period in which a current pulse is not output (the current pulse is off) (see the waveform diagrams of the tenth stage in . Fig.5 to 9). The pulse signal Spls can be a binary signal comprising alternating high-level sections representing a current pulse-on period and low-level sections representing a current pulse-off period. In this case, the circuit receiving the pulse signal Spls should be configured to perform the operation to be carried out during the current pulse-on period, and the operation to be carried out during the current pulse-off period, respectively, in the high-level section and the low-level section of the pulse signal Spls.

[0036] The current pulse generation circuit 4 short-circuits between the second output end 3b and the first output end 3a during the current pulse off period, and opens between the second output end 3b and the first output end 3a during the current pulse on period, thus generating a current pulse from an inductor current II, which is smoothed by the smoothing inductor 2. This current pulse is output to the load 32 via output end 3. This current pulse is therefore an output current lout.

[0037] With reference to Fig.In an example of a specific circuit configuration of the main part of the pulse driver circuit 100, the current pulse generation circuit 4 comprises a switching element Q6 with a high-potential main terminal (here a drain of an N-channel FET) connected to the second output end 3b, and a low-potential main terminal (here a source of the N-channel FET) connected to the first output end 3a. The switching element Q6 has a control terminal (here a gate of the N-channel FET) which receives the pulse signal Spls from the control device 33 via a driver circuit (not shown). A snubber circuit is connected in parallel to the switching element Q6.

[0038] The switching element Q6, for example, contains a transistor such as a FET, a bipolar transistor, or an IGBT. Here, switching element Q6 contains an N-channel FET. The snubber circuit here includes a high-pass filter in which a resistor R1 and a capacitor C1 are connected in series.

[0039] The switching element Q6 is switched on when the control terminal receives a high-level pulse signal Spls, and shorts between the second output end 3b and the first output end 3a. The inductor current II, which is output from the high-potential output end 1b of the DC-DC converter circuit 1 (cathode of the freewheeling diode D3), thus flows back via the smoothing inductor 2 and the switching element Q6 to the low-potential output end 1a of the DC-DC converter circuit 1 (the anode of the freewheeling diode D3). The switching element Q6 is then switched off when the control terminal receives a low-level pulse signal Spls, and opens between the second output end 3b and the first output end 3a.The inductor current output from the high-potential output 1b of the DC-DC converter circuit 1 (cathode of the freewheeling diode D3) flows via the smoothing inductor 2, the second output 3b, the load 32, and the first output 3a back to the low-potential output 1a of the DC-DC converter circuit 1 (anode of the freewheeling diode D3). In this way, the current pulse generation circuit 4 generates a current pulse, which is then output to the load 32 via output 3. Throttle current sensor 5

[0040] With reference to Fig. 1 and Fig.In the section between the high-potential output end 1b of the DC-DC converter circuit 1 and a connection point Nd of the second output end 3b with the current pulse generation circuit 4, the inductor current II is located in the current path. The inductor current sensor 5 detects the inductor current II in the section between the high-potential output end 1b and the connection point Nd of the second output end 3b with the current pulse generation circuit 4 and outputs the detected inductor current IId. The inductor current sensor 5 could be, for example, a resistance sensor, a Hall effect sensor, a magnetic impedance sensor, etc. Throttle current control circuit 6

[0041] With reference to Fig.1 The throttle current control circuit 6 is an error amplification circuit of the throttle current II and outputs a throttle current command Ci based on an error of the throttle current IId detected by the throttle current sensor 5 with reference to the throttle current target value Ilset, which is entered from the control device 33.

[0042] Fig. Figure 4 is a circuit diagram that shows an example of a specific circuit configuration of a control system of the pulse driver circuit 100. Fig. 1 represents. With reference to Fig.In an example of a specific circuit configuration of the control system of the pulse driver circuit 100, the inductor current control circuit 6 comprises an operational circuit including an operational amplifier 52. A non-inverting input terminal of the operational amplifier 52 is connected to ground. A resistor R1 and a resistor R2 are connected in parallel to an inverting input terminal. A capacitor C2 is connected between the inverting input terminal and an output terminal of the operational amplifier 52, and a resistor R3 and a capacitor C3, connected in series, are connected in parallel to the capacitor C2.

[0043] Therefore, this operational circuit comprises an integration circuit formed by resistor R1, resistor R2, and capacitor C2; a proportional-integral (Pl) compensator formed by resistor R1, resistor R2, resistor R3, and capacitor C3; and an addition circuit formed by resistor R1 and resistor R2, with respect to operational amplifier 52. Resistor R1 receives a voltage corresponding to the inductor current target value Ilset with inverted polarities. Resistor R2 receives a voltage corresponding to the inductor current IId detected by the inductor current sensor 5. The difference between the detected inductor current IId and the inductor current target value Ilset is thus amplified, incompletely integrated, inverted, and output from operational amplifier 52.In other words, an error in the detected inductor current IId with respect to the inductor current target value Ilset is subjected to PI control and output as the inductor current instruction Ci from the operational amplifier 52. Double-ended choke voltage sensor 7

[0044] With reference to Fig. 1 and Fig. 3. The two-terminal inductor voltage sensor 7 detects a two-terminal voltage VI of the smoothing inductor 2 and outputs the detected voltage VId (hereinafter referred to as the detected two-terminal inductor voltage). The two-terminal inductor voltage sensor 7 is, for example, a resistance sensor, a capacitor sensor, etc. Double-ended voltage averaging circuit 8

[0045] With reference to Fig.1. The two-terminal voltage averaging circuit 8 generates a voltage (hereinafter referred to as the averaged two-terminal inductor voltage) Vla, which is obtained by averaging the detected two-terminal inductor voltage VId of the smoothing inductor 2, which is detected by the two-terminal inductor voltage sensor 7, and outputs the voltage. With reference to Fig.Figure 4, comprising the two-terminated voltage averaging circuit 8 in an example of a specific circuit configuration of the control system of the pulse driver circuit 100, includes a resistor R4, a resistor R5, and a capacitor C4. Resistor R4 has one high-potential end connected to an on / off switch 53, and the other end is connected to ground. Resistor R5 and capacitor C4, connected in series, are connected to both ends of resistor R4. One junction of resistor R5 and capacitor C4 is connected to resistor R7, which is an input element of the two-terminated choke voltage control circuit 9.

[0046] The on / off switch 53 receives the pulse signal Spls from the control device 33 and receives the two-terminal inductor voltage Vld detected by the two-terminal inductor voltage sensor 7. When the on / off switch 53 receives a high-level pulse signal Spls, representing the current pulse off period, the on / off switch 53 is turned on and inputs the detected two-terminal inductor voltage VId into the high-potential end of resistor R4. When the on / off switch 53 receives a low-level pulse signal Spls, representing the current pulse on period, the on / off switch 53 is turned off and interrupts the input of the detected two-terminal inductor voltage Vld. Resistor R5 and capacitor C4 then form a low-pass filter, and the low-pass filter averages (smooths) the detected two-terminal inductor voltage VId that is input to resistor R4.The averaged double-ended choke voltage Vla is fed into the resistor R7, which is an input element of the double-ended choke voltage control circuit 9. Double-ended choke voltage control circuit 9

[0047] With reference to Fig. 1. The two-terminal inductor voltage control circuit 9 is an error amplification circuit of the two-terminal inductor voltage VI and outputs a two-terminal inductor voltage command Cvl based on an error of the averaged two-terminal inductor voltage Vla, which is averaged by the two-terminal voltage averaging circuit 8, with respect to a target value Vlset of the two-terminal inductor voltage. The target value Vlset of the two-terminal inductor voltage is stored in a memory unit 22 for the target value of the two-terminal inductor voltage. The memory unit 22 for the target value of the two-terminal inductor voltage comprises an element such as a suitable circuit or a suitable memory.

[0048] With reference to Fig. Figure 4, in an example of a specific circuit configuration of the control system of the pulse driver circuit 100, comprises the two-terminated inductor voltage control circuit 9, a constant voltage source 54, and an operational circuit including an operational amplifier 55. The voltage of the constant voltage source 54 is set to a predetermined target value Vlset of the two-terminal inductor voltage. Thus, the constant voltage source 54 forms the storage unit 22 for the target value of the two-terminal inductor voltage. Fig.1. The target value Vlset of the inductor voltage is set to "a voltage of 0 V or a predetermined voltage close to 0 V". Taking into account the resistance component of the smoothing inductor and the range of the inductor current, the target value Vlset of the inductor voltage is set to 0 V or a suboptimal voltage value. This voltage value of 0 V or a suboptimal voltage value is "a voltage of 0 V or a predetermined voltage close to 0 V".Since the target value Vlset of the inductor voltage deviates from the ideal voltage value, the feedback control of the inductor voltage VI has a less than adequate function for adjusting the energy output from the DC-DC converter circuit 1 to the energy consumed by the load (here, by the internal resistance of the constant current source) during a rapid decrease in the load of the constant current source (the DC-DC converter circuit 1 and the smoothing inductor 2). "A voltage of 0 V or a predetermined voltage close to 0 V" is determined by design, experimentation, simulation, or the like. For example, "a voltage of 0 V or a predetermined voltage close to 0 V" is a voltage in the range of 5% of a set output voltage of the DC-DC converter circuit 1.The voltage in the range of 5% of the set output voltage of the DC-DC converter circuit 1 is a voltage within a range with a lower limit of 0 V and an upper limit of 5% of the set output voltage of the DC-DC converter circuit 1. The absolute value of the terminal inductor voltage VI can be equal to or higher than the set output voltage of the DC-DC converter circuit 1 at the moment when the load of the constant current source rapidly decreases. A voltage of 5% of the set output voltage of the DC-DC converter circuit can therefore be considered a voltage close to 0 V as the target value Vlset of the terminal inductor voltage during feedback control of the terminal inductor voltage VI.If the target value Vlset of the inductor voltage is a voltage in the range of 5% of the set output voltage of the DC-DC converter circuit 1, the feedback control of the inductor voltage VI can appropriately adjust the energy output from the DC-DC converter circuit 1 to the energy consumed by the load during a rapid decrease in the load of the constant current source. "A voltage of 0 V or a predetermined voltage close to 0 V" is set here to approximately 50 mV (approximately 0.04% of the set output voltage (for example, 120 V) of the DC-DC converter circuit 1).

[0049] A non-inverting input terminal of operational amplifier 55 is connected to ground. Resistor R6 and resistor R7 are connected in parallel to an inverting input terminal. A capacitor C5 is connected between the inverting input terminal and an output terminal of operational amplifier 55, and resistor R8 and capacitor C6, connected in series, are connected in parallel to capacitor C5.

[0050] Therefore, this operational circuit comprises an integration circuit formed by resistor R6, resistor R7, and capacitor C5; a PI compensator formed by resistor R6, resistor R7, resistor R8, and capacitor C6; and an addition circuit formed by resistor R6 and resistor R7, with respect to operational amplifier 55. Resistor R6 receives the target value Vlset of the inductor voltage with inverted polarity. Resistor R7 receives the averaged inductor voltage Vla, which is averaged by the inductor voltage averaging circuit 8. The difference between the averaged inductor voltage Vla and the target value Vlset of the inductor voltage is thus amplified, incompletely integrated, inverted, and output from operational amplifier 55.In other words, an error of the averaged two-terminal inductor voltage Vla with respect to the target value Vlset of the two-terminal inductor voltage is subjected to PI control and output as the two-terminal inductor voltage instruction Cvl from the operational amplifier 55. Command selection circuit 10

[0051] With reference to Fig. 1. The command selection circuit 10 receives the pulse signal Spls from the control device 33 and, during the current pulse on period, selects the inductor current command Ci and outputs this command as the selection command Cmd. During the current pulse off period, the command selection circuit 10 selects the two-terminated inductor voltage command Cvl and outputs this command as the selection command Cmd. With reference to Fig. 4 includes, in an example of a specific circuit configuration of the control system of the pulse driver circuit 100, the command selection circuit 10 a selector switch 56.

[0052] Selector switch 56 receives the pulse signal Spls from the control device 33. When selector switch 56 receives a low-level pulse signal Spls corresponding to the current pulse-on period, it switches the connection destination of the PWM signal generation circuit 11 to the inductor current control circuit 6. The inductor current control circuit 6 then outputs the inductor current command Ci as a selection command Cmd to the PWM signal generation circuit 11. When selector switch 56 receives a high-level pulse signal Spls representing the current pulse-off period, it switches the connection destination of the PWM signal generation circuit 11 to the two-terminated inductor voltage control circuit 9. The two-terminated inductor voltage control circuit 9 then outputs the two-terminated inductor voltage command Cvl as a selection command Cmd to the PWM signal generation circuit 11. PWM signal generation circuit 11

[0053] With reference to Fig.1. The PWM signal generation circuit 11 generates one or more PWM signals Spwm corresponding to one or more switching elements (Q1 to Q4 (see Fig. 2) or Q5 (see Fig. 3)) of the DC voltage converter circuit 1 according to the choke current command Ci or the double-ended choke voltage command Cvl as selection command Cmd, which is output from the command selection circuit 10, and outputs the one or more PWM signals Spwm to the one or more switching elements (Q1 to Q4 or Q5).

[0054] With reference to Fig.In an example of a specific circuit configuration of the control system of the pulse driver circuit 100, the PWM signal generation circuit 11 comprises a first PWM signal generation unit 11a and a second PWM signal generation unit 11b, which is connected in parallel with the command selection circuit 10. This configuration is applied to the case of a DC-DC converter circuit 1, which is implemented by a circuit using the full-bridge inverter 41. Fig. 2 is formed.

[0055] The first PWM signal generation unit 11a comprises a comparator 57, a signal source 58, an AND gate 59, and a signal source 60. The comparator 57 has a non-inverting input terminal that receives the selection command Cmd from the command selection circuit 10. The comparator 57 also has an inverting input terminal that receives a triangular wave with a predetermined carrier frequency (for example, 200 kHz) from the signal source 58, which is connected to ground. Thus, the comparator 57 outputs a PWM signal with a pulse width corresponding to the value of the selection command Cmd. This PWM signal is fed into one input terminal of the AND gate 59. The other input terminal of the AND gate 59 receives a first binary signal with a duty cycle of 50% and a frequency (100 kHz) of 1 / 2 the predetermined carrier frequency from the signal source 60, which is connected to ground.Thus, during a high-level period of the first binary signal, the PWM signal from the comparator 57 is output as the first PWM signal Spwm from the AND circuit 59.

[0056] The second PWM signal generation unit 11b comprises a comparator 61, a signal source 62, an AND gate 63, and a signal source 64. The comparator 61 has a non-inverting input terminal that receives the selection command Cmd from the command selection circuit 10. The comparator 61 also has an inverting input terminal that receives a triangular wave with the predetermined carrier frequency (200 kHz) from the signal source 62, which is connected to ground. Thus, the comparator 61 outputs a PWM signal with a pulse width corresponding to the value of the selection command Cmd. This PWM signal is fed into one input terminal of the AND gate 63. The other input terminal of the AND gate 63 receives a first binary signal with a duty cycle of 50% and a frequency (100 kHz) of 1 / 2 the predetermined carrier frequency from the signal source 64, which is connected to ground.However, the phase of the second binary signal is delayed by 180° relative to the phase of the first binary signal of the first PWM signal generation unit 11a. Thus, during a high-level period of the second binary signal, which corresponds to a low-level period of the first binary signal, the PWM signal from the comparator 61 is output as the second PWM signal Spwm from the AND circuit 63.

[0057] The first PWM signal Spwm and the second PWM signal Spwm are fed into the set of switching element Q1 and switching element Q2, respectively, and the set of switching element Q3 and switching element Q4 of the DC-DC converter circuit 1. Fig. 2 entered.

[0058] In this case, the DC-DC converter circuit 1 uses the voltage-reducing chopper. Fig.3 includes the PWM signal output from the comparator 57 of the first PWM signal generation unit 11a as PWM signal Spwm into the switching element Q5 of the DC voltage converter circuit 1 from Fig. 3 entered.

[0059] Software can be used to form the choke current control circuit 6, the double-ended voltage averaging circuit 8, the double-ended choke voltage control circuit 9 and the command selection circuit 10. Operation

[0060] The operation of the pulse driver circuit 100 with training as described above will now be discussed with reference to Fig. 1 described. If, with reference to Fig.When one or more switching elements in the DC-DC converter circuit 1 are switched on and off according to the PWM signal Spwm input from the PWM signal generation circuit 11, the DC-DC converter circuit 1 outputs a square-wave DC output voltage Vout with a pulse width corresponding to the PWM signal Spwm from the DC voltage input of the DC power supply 31. The smoothing inductor 2 smooths the inductor current II according to the square-wave DC output voltage Vout output from the DC-DC converter circuit 1. From the smoothed inductor current II, the current pulse generation circuit 4 generates a current pulse as the output current lout according to the pulse signal Spls input from the control device 33.More precisely, the current pulse generation circuit 4 short-circuits between the second output end 3b and the first output end 3a during the current pulse off period of the pulse signal Spls, opens between the second output end 3b and the first output end 3a during the current pulse on period of the pulse signal Spls, and thus generates a current pulse as the output current lout from the inductor current II.

[0061] The inductor current sensor 5 detects the inductor current II. The inductor current control circuit 6 outputs the inductor current command Ci based on an error in the inductor current IId detected by the inductor current sensor 5, relative to the target inductor current value Ilset input from the control device 33. The two-terminal inductor voltage sensor 7 detects the two-terminal inductor voltage VI of the smoothing inductor 2. The two-terminal voltage averaging circuit 8 generates a voltage, obtained by averaging the detected two-terminal inductor voltage VId of the smoothing inductor 2, which is detected by the two-terminal inductor voltage sensor 7, and outputs this voltage. The two-terminated choke voltage control circuit 9 outputs the two-terminated choke voltage command Cvl based on an error of the averaged two-terminal choke voltage Vla, which is averaged by the two-terminal voltage averaging circuit 8, with reference to the target value Vlset of the two-terminal choke voltage.The command selection circuit 10 receives the pulse signal Spls from the control device 33 and, during the current pulse-on period of the pulse signal Spls, selects the inductor current command Ci and outputs this command as the selection command Cmd. During the current pulse-off period of the pulse signal Spls, the command selection circuit 10 selects the two-terminal inductor voltage command Cvl and outputs this command as the selection command Cmd. The PWM signal generation circuit 11 generates one or more PWM signals Spwm according to one or more switching elements (Q1 to Q4 or Q5) according to the inductor current command Ci or the two-terminal inductor voltage command Cvl as the selection command Cmd from the command selection circuit 10 and inputs the one or more PWM signals Spwm into the DC-DC converter circuit 1. Function and effect

[0062] The function and effect of the pulse driver circuit 100, which is designed and operates as described above, will now be described based on simulation results. simulation

[0063] This simulation was developed for the in Fig. 3 and Fig. The pulse driver circuit 100 shown in Figure 4 was performed. In this simulation, Examples 1 and 2 and Comparative Examples 1 to 3 of the present disclosure were carried out. Table 1 shows the conditions of the operation. The current pulse, which is the output current lout, has a set duty cycle of 50%. The "set output voltage value" is a set output voltage of the DC-DC converter circuit 1 when a predetermined load 32 is connected. Table 1 Implementation objective Control for current pulse one-period Control for current pulse-off period Pulse rate Throttle current target value Set output voltage value First comparative example Throttle current control Throttle current control 1 kHz 150 A 120 V Second comparative example Throttle current control Throttle current control 10 kHz 150 A 120 V Third comparative example Throttle current control Throttle current control 50 kHz 150 A 120 V First example Throttle current control Double-ended choke voltage control 1 kHz 150 A 120 V Second example Throttle current control Double-ended choke voltage control 10 kHz 150 A 120 V

[0064] In this simulation, the following parameters were measured: the output current lout, which was a current pulse supplied to the load 32; the inductor current II; the output voltage Vout1 of the DC-DC converter circuit 1; the voltage Vout2 on the output side of the smoothing inductor 2 (the side of the junction Nd between the second output end 3b and the current pulse generation circuit 4); the detected inductor voltage Vld, which was a detected voltage of the inductor voltage VI (corresponding to Vout1-Vout2); the averaged inductor voltage Vla, which was an output voltage of the inductor voltage averaging circuit 8; and the voltage of the inductor current command Ci (the output voltage of the operational amplifier 52). Fig. 4), the voltage of the double-ended choke voltage command Cvl (the output voltage of the operational amplifier 55 from Fig. 4), the voltage of the selection command Cmd and the voltage of the pulse signal Spls. Fig.Figures 5 to 9 show the waveforms of these parameters. Waveform diagram

[0065] The waveform diagrams from Fig. Stages 5 to 9 were generated by tracking the waveforms of the images output by the simulation device. The areas designated A to C in the waveform diagrams of stages four and five in Fig. 5 and the areas designated by reference symbols D to E in the waveform diagrams of the fourth to fifth stage in Fig. 8 are represented with suitable semi-transparent patterns because in these areas the pulses are densely arranged at very small intervals with a duty cycle of almost 100% and if the pulse waveforms are drawn in a solid line of normal thickness, the pulse waveforms will be filled with the solid line and cannot be drawn.

[0066] Fig.Figure 5 shows waveform diagrams of results from an operational simulation of a pulse driver circuit (first comparative example) that only performs feedback control of a choke current II on a DC voltage converter circuit 1 at a current pulse that has a frequency of 1 kHz. Fig. Figure 6 shows waveform diagrams of results from an operating simulation of a pulse driver circuit (second comparative example) that only performs feedback control of a choke current II on a DC voltage converter circuit 1 at a current pulse that has a frequency of 10 kHz. Fig. Figure 7 shows waveform diagrams of results from an operating simulation of a pulse driver circuit 100 (third comparative example), which only performs feedback control of a choke current II on a DC voltage converter circuit 1 at a current pulse that has a frequency of 50 kHz. Fig.Figure 8 shows waveform diagrams of results from an operational simulation of a pulse driver circuit (first example) that performs feedback control of a two-ended inductor voltage VI during a current pulse off period and provides feedback control of an inductor current II during a current pulse on period on a DC-DC converter circuit 1 at a current pulse having a frequency of 1 kHz. Fig. Figure 9 shows waveform diagrams of results from an operating simulation of a pulse driver circuit 100 (second example) which performs feedback control of a two-ended inductor voltage VI during a current pulse off period and provides feedback control of an inductor current II during a current pulse on period on a DC voltage converter circuit 1 at a current pulse having a frequency of 10 kHz.

[0067] In Fig.In stages 5 through 9, the horizontal axis of the waveform diagram of each stage, shown in the waveform diagram of the lowest stage, indicates the time (ms) common to all stages. The vertical axis of the waveform diagram of each stage indicates a physical quantity specific to that stage's waveform diagram.

[0068] The waveform diagram of the top stage is a waveform diagram of the output current lout. The vertical axis indicates the current (A). The waveform diagram of the second stage is a waveform diagram of the output current lout with a vertical axis on a larger scale. The vertical axis indicates the current (A) on a larger scale. The waveform diagram of the third stage is a waveform diagram of the inductor current II. As in the waveform diagram of the second stage, the vertical axis indicates the current (A) on a larger scale.

[0069] The waveform diagram of the fourth stage comprises the waveform diagram of the output voltage Vout1 of the DC-DC converter circuit 1 and the waveform diagram of the voltage Vout2 on the output side of the smoothing inductor 2. The vertical axis represents the voltage (V). In the waveform diagram of this stage, the solid line represents the waveform diagram of the output voltage Vout1 of the DC-DC converter circuit 1, and the alternating long and short dashed line represents the waveform diagram of the voltage Vout2 on the output side of the smoothing inductor 2. The waveform diagram of the output voltage Vout1 of the DC-DC converter circuit 1 shows the appearance of a pulse of a square-wave DC voltage with a pulse width and frequency corresponding to the pulse width and carrier frequency of the PWM signal Spwm.

[0070] The waveform diagram of the fifth stage is a waveform diagram of the detected inductor voltage VId (inductor voltage VI). This waveform diagram shows the appearance of a waveform of Vout1-Vout2. When the inductor voltage VI has a positive value, the smoothing inductor 2 stores energy, while the inductor voltage VI suppresses an increase in the inductor current II. When the detected inductor voltage VId has a negative value, the inductor voltage VI suppresses a decrease in the inductor current II, while the stored energy is released from the smoothing inductor 2.

[0071] The waveform diagram of the sixth stage is a waveform diagram of the averaged two-terminal inductor voltage Vla. The vertical axis indicates the voltage (V). The averaged two-terminal inductor voltage Vla represents the voltage of a signal obtained by averaging the measured two-terminal inductor voltage VId and VI through a low-pass filter and multiplying the gain by 1 / 25.

[0072] The waveform diagram of the seventh stage is a waveform diagram of the inductor current command Ci. The vertical axis indicates the voltage (V). The inductor current command Ci corresponds to the duty cycle of the square-wave DC voltage of the DC-DC converter circuit 1. A voltage from 0 V to 3 V corresponds to a duty cycle of 0% to 100%.

[0073] The waveform diagram of the eighth stage is a waveform diagram of the two-terminal choke voltage command Cvl. The vertical axis indicates the voltage (V). The two-terminal choke voltage command Cvl corresponds to the duty cycle of the square-wave DC voltage of the DC-DC converter circuit 1. A voltage from 0 V to 3 V corresponds to a duty cycle of 0% to 100%.

[0074] The waveform diagram of the ninth stage is a waveform diagram of the Cmd selection command. The vertical axis indicates the voltage (V). In the first to third comparison examples ( Fig. In stages 5 to 7, the selection command Cmd is always the inductor current command Ci, and therefore the waveform diagram of the selection command Cmd is the same as the waveform diagram of the inductor current command Ci of the seventh stage. In the first and second examples ( Fig. 8 and Fig.9) The selection command Cmd is the inductor current command Ci when the pulse signal Spls is in the current pulse-on period (low level), and when the pulse signal Spls is in the current pulse-off period (high level), the selection command Cmd is the two-terminated inductor voltage command Cvl. Therefore, when the pulse signal Spls is in the current pulse-on period (low level), the waveform diagram of the selection command Cmd is the same as the waveform diagram of the inductor current command Ci of the seventh stage, and when the pulse signal Spls is in the current pulse-off period (high level), the waveform diagram of the selection command Cmd is the same as the waveform diagram of the two-terminated inductor voltage command Cvl of the eighth stage.

[0075] The tenth stage shows a waveform diagram of the pulse signal Spls. The level of the pulse signal Spls is a low level during the current pulse on period and a high level during the current pulse off period. Evaluation: First comparison example

[0076] With reference to Fig. In the waveform diagram of the first to second stage, a ripple of ΔI = 39 A in the output current lout occurs in the first comparison example.

[0077] In the waveform diagram of the third stage, the inductor current II is not sufficiently smoothed by the smoothing inductor 2 due to the relatively low pulse frequency of 1 kHz, so that the waveform in the current pulse-on period appears in the waveform of the insufficiently smoothed inductor current II, as it is, in the waveform of the output current lout and thus a ripple of ΔI = 39 A occurs.

[0078] In the waveform diagram of the fourth stage, the voltage Vout2 on the output side of the smoothing inductor 2 (alternating long and short dashed line) changes rapidly between the current pulse on period and the current pulse off period, in the range of 120 V to 0 V. The output voltage Vout1 of the DC-DC converter circuit 1 changes between the constant-amplitude voltage and essentially 0 V after the change in the voltage Vout2, which is the load voltage, on the output side of the smoothing inductor 2. This means that the feedback control of the inductor current II follows the rapid change in the load voltage with a delay. Furthermore, the output voltage Vout1 of the DC-DC converter circuit 1 is divided into a period in which the pulses are closely spaced according to the PWM signal (areas designated A to C) and a period in which pulses are absent.In the periods designated by reference symbols A to C, the pulse width corresponding to the PWM signal is proportional to the size of the choke current command Ci in the waveform diagram of the seventh stage.

[0079] In the waveform diagram of the fifth to sixth stage, the measured inductor voltage VId and the averaged inductor voltage Vla have positive values ​​in the initial period of the current pulse off period. This means that the smoothing inductor 2 suppresses an increase in the inductor current II during the current pulse off period.

[0080] In the waveform diagram of the seventh stage, the value of the inductor current command Ci approaches approximately the voltage corresponding to a 100% duty cycle during the current pulse-on period. During the current pulse-off period, the value of the inductor current command Ci becomes approximately 0 V, corresponding to a 0% duty cycle. However, after switching from the current pulse-off period to the current pulse-on period, the inductor current command Ci gradually increases from 0 V to a value close to the voltage corresponding to a 100% duty cycle, and after switching from the current pulse-on period to the current pulse-off period, it gradually decreases from a value close to the voltage corresponding to a 100% duty cycle to 0 V.

[0081] In summary, the description of the waveform diagram of the fourth to seventh stages means that during the current pulse-off period, the feedback control of the inductor current II follows the rapid change in the load voltage with a delay. Therefore, despite the suppression of an increase in inductor current II by the smoothing inductor 2, the inductor current II far exceeds the target value Ilset. Consequently, at the end of the current pulse-off period, the inductor current II does not decrease to the target value Ilset, even when the inductor current command Ci assumes a value of 0 V. In steady state, the energy stored by the smoothing inductor 2 is equal to the energy released from the smoothing inductor 2. Conversely, the above description means that the inductor current II at the end of the current pulse-on period is lower than the target value Ilset.In fact, the waveform of the inductor current II at the second stage is as described above.

[0082] In the waveform diagram of the eighth stage in the first comparison example, no feedback control of the inductor voltage is performed, and therefore the inductor voltage command Cvl is not issued. Therefore, in the waveform diagram of the ninth stage, the selection command Cmd has the same waveform as the inductor current command Ci in the waveform diagram of the seventh stage. Second comparative example

[0083] With reference to Fig. 6. In the waveform diagram of the first to second stage, a ripple of ΔI = 14 A in the output current lout occurs in the second comparison example.

[0084] In the waveform diagram of the third stage, the inductor current II is smoothed to a certain degree by the smoothing inductor 2 due to the relatively high pulse frequency of 10 kHz, so that the waveform in the current pulse-on period appears in the waveform of the inductor current II, smoothed to a certain degree, as it is, in the waveform of the output current lout, and thus a ripple of ΔI = 14 A occurs.

[0085] In the waveform diagram of the fourth stage, the voltage Vout2 on the output side of the smoothing inductor 2 (alternating long and short dashed line) changes rapidly between the current pulse on period and the current pulse off period, ranging from 120 V to 0 V. The pulse, which corresponds to the PWM signal of the output voltage Vout1 of the DC-DC converter circuit 1 (hereinafter sometimes referred to as the "pulse of output voltage Vout1"), has a constant amplitude, independent of the change in the voltage Vout2, which is the load voltage, on the output side of the smoothing inductor 2. However, the pulse width of the output voltage Vout1 of the DC-DC converter circuit 1 changes according to a change in the inductor current II.

[0086] In the waveform diagram of the fifth stage, the measured inductor voltage Vld has a negative value during the current pulse on period and a positive value during the current pulse off period. In the waveform diagram of the seventh stage, the inductor current Ci increases monotonically during the current pulse on period and decreases monotonically during the current pulse off period.

[0087] During the current pulse-on period, the inductor voltage VI at both ends thus suppresses a decrease in the inductor current II, and during the current pulse-off period, the inductor voltage VI at both ends suppresses an increase in the inductor current II.

[0088] In summary, it is clear from the foregoing that in the second comparative example, the feedback control of the inductor current II cannot follow the rapid change in the load voltage due to the relatively high pulse frequency of 10 kHz, and thus only the smoothing inductor 2 smooths the inductor current II, which fluctuates due to the rapid change in the load voltage. Third comparative example

[0089] With reference to Fig. In the waveform diagram of the first to second stage, in the third comparison example, there is almost no ripple in the output current lout.

[0090] In the waveform diagram of the fourth stage, the voltage Vout2 on the output side of the smoothing inductor 2 (alternating long and short dashed line) changes rapidly between the current pulse on period and the current pulse off period in the range of 120 V to 0 V. The pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has a substantially constant amplitude and width, independent of the change in the voltage Vout2, which is the load voltage, on the output side of the smoothing inductor 2.

[0091] In the waveform diagram of the fifth stage, the measured inductor voltage Vld has a negative value during the current pulse-on period and a positive value during the current pulse-off period. In the waveform diagram of the seventh stage, the inductor current Ci increases monotonically slightly during the current pulse-on period and decreases monotonically slightly during the current pulse-off period.

[0092] During the current pulse-on period, a decrease in the inductor current II is thus somewhat suppressed by the inductor voltage VI at both ends, and during the current pulse-off period, an increase in the inductor current II is somewhat suppressed by the inductor voltage VI at both ends.

[0093] In summary, it is clear from the foregoing that in the third comparative example, the feedback control of the inductor current II cannot follow the rapid change in the load voltage due to the significantly high pulse frequency of 50 kHz, and thus only the smoothing inductor 2 almost completely smooths the inductor current II, which fluctuates due to the rapid change in the load voltage. First example

[0094] With reference to Fig.In the waveform diagram of the first to second stage, the first example shows a ripple of ΔI = 3.0 A in the output current lout. In this example, the ripple is significantly improved compared to comparison examples 1 and 2.

[0095] In the waveform diagram of the third stage, the inductor current II is essentially constant. The waveform in the current pulse-on period, in the waveform of the essentially constant inductor current II, appears as is in the waveform of the output current lout, and thus an improved ripple of ΔI = 3.0 A occurs.

[0096] In the waveform diagram of the fourth stage, the voltage Vout2 on the output side of the smoothing inductor 2 (alternating long and short dashed line) changes rapidly between the current pulse on period and the current pulse off period, ranging from 120 V to 0 V. The change in the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 coincides with the change in the voltage Vout2, which is the load voltage, on the output side of the smoothing inductor 2. During the current pulse on period, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 thus has the waveform in the period denoted by reference symbol D, and during the current pulse off period, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has a waveform with constant amplitude and an extremely narrow width, with a duty cycle close to 0%.In the period designated by reference symbol D, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has a constant amplitude and a width corresponding to a value (a magnitude) close to the voltage that corresponds to the 100% on-duty cycle of the select command Cmd (choke current command Ci), as shown in the waveform diagram of the ninth stage. Thus, the output voltage Vout1 of the DC-DC converter circuit 1 assumes a value of 120 V, which is the set output voltage, during the current pulse-on period, and essentially assumes a value of 0 V during the current pulse-off period.

[0097] In the waveform diagram of the fifth stage, the detected inductor voltage Vld during the current pulse-on period has the waveform of the period designated by reference E. During the current pulse-off period, the detected inductor voltage VId has a waveform with an amplitude that is essentially 0 V smaller than the waveform in the current pulse-off period of the waveform diagram of the fourth stage. In the period designated by reference E, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has the same width as in the period designated by reference D in the waveform diagram of the fourth stage and an amplitude obtained by subtracting "120 V" and inverting the polarity.

[0098] In the waveform diagram of the sixth stage, the average voltage across both ends of the inductor, Vla, is essentially 0 V. This means that the smoothing inductor 2 smooths the inductor current II less effectively. This follows automatically because, during the current pulse-off period, the voltage across both ends of the inductor is controlled by feedback control of the voltage across both ends of the inductor to "a voltage of 0 V or a predetermined voltage close to 0 V". However, even during the current pulse-on period, the average voltage across both ends of the inductor, Vla, is essentially 0 V, although the feedback control of the voltage across both ends of the inductor is not performed; this has interesting technical significance.

[0099] In the waveform diagram of the seventh stage, the choke current command Ci generally has a constant value (constant quantity) close to the voltage corresponding to a 100% duty cycle.

[0100] In the waveform diagram of the eighth stage, the two-terminal inductor voltage command Cvl has a value essentially close to 0 V during the current pulse off period. During the current pulse on period, the two-terminal inductor voltage command Cvl has a voltage value corresponding to an on duty cycle of approximately 30%. While this phenomenon is not advantageous, it has no effect on the ripple of the output current lout, since the two-terminal inductor voltage command Cvl is not issued as a selection command Cmd during the current pulse on period. Therefore, this phenomenon can be disregarded. However, the cause is described here. During the current pulse on period, the on / off switch 53 is off, and therefore the two-terminal voltage averaging circuit 8 does not receive the detected two-terminal inductor voltage Vld. As a result, the electrical charge of capacitor C4 is discharged through resistor R4 and resistor R5.Therefore, the averaged voltage between the two terminals, Vla, becomes lower than the target value Vlset of the voltage between the two terminals, the "predetermined voltage close to 0 V," and thus the voltage between the two terminals, Cvl, increases gradually. This is the cause of the phenomenon mentioned above. As a basic solution to this phenomenon, it suffices, for example, that the voltage averaging circuit 8 and the voltage control circuit 9 are implemented in software, and that the previously averaged voltage between the two terminals, Vla, is stored and output during the current pulse on period.

[0101] In the waveform diagram of the ninth stage, the select command Cmd has a constant value close to the voltage corresponding to the 100% on-duty cycle of the inductor current command Ci on the seventh stage during the current pulse-on period. During the current pulse-off period, the select command Cmd has a value essentially close to 0 V of the two-terminated inductor voltage command Cvl on the eighth stage. As described above, the output voltage pulse Vout1 of DC-DC converter circuit 1 thus has a waveform with a relatively wide width during the current pulse-on period and an extremely narrow width during the current pulse-off period, so that the output voltage Vout1 of DC-DC converter circuit 1 assumes a value of 120 V, which is the set output voltage, during the current pulse-on period, and becomes "essentially 0 V" during the current pulse-off period, a voltage necessary to maintain the inductor current target value Ilset. Second example

[0102] The second example is similar to the first, except that the pulse rate is higher. However, due to the higher pulse rate, the function and effect of the present disclosure are clearer in the second example.

[0103] With reference to Fig. In the waveform diagram of the first to second stage, the second example shows a ripple of ΔI = 1.5 A in the output current lout. In this example, the ripple is significantly improved compared to comparison examples 1 and 2.

[0104] In the waveform diagram of the fourth stage, the voltage Vout2 on the output side of the smoothing inductor 2 (alternating long and short dashed line) changes rapidly between the current pulse-on period and the current pulse-off period, ranging from 120 V to 0 V. The change in the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 coincides with the change in the voltage Vout2, which is the load voltage, on the output side of the smoothing inductor 2. Thus, during the current pulse-on period, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has a waveform with a constant amplitude and a relatively wide width, and during the current pulse-off period, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 has a waveform with a constant amplitude, an extremely narrow width, and a relatively long pulse interval.Thus, the output voltage Vout1 of the DC-DC converter circuit 1 assumes the value 120 V, which is the set output voltage, during the current pulse-on period, and essentially assumes the value 0 V during the current pulse-off period.

[0105] In the waveform diagram of the fifth stage, the detected inductor voltage VId has a waveform with the same width as the pulse of the output voltage Vout1 in the waveform diagram of the fourth stage, and with an amplitude obtained by subtracting "120 V" and inverting the polarity during the current pulse-on period. During the current pulse-off period, the detected inductor voltage VId has a waveform with an amplitude that is essentially 0 V smaller than the waveform in the current pulse-off period of the waveform diagram of the fourth stage.

[0106] The waveform diagram of the sixth to eighth stage is essentially the same as in the first example.

[0107] In the waveform diagram of the ninth stage, the select command Cmd has a constant value close to the voltage corresponding to the 100% on-duty cycle of the inductor current command Ci on the seventh stage during the current pulse-on period. During the current pulse-off period, the select command Cmd has a value essentially close to 0 V of the two-terminated inductor voltage command Cvl on the eighth stage. As described above, the pulse of the output voltage Vout1 of the DC-DC converter circuit 1 thus has a waveform with a relatively wide width during the current pulse-on period and with an extremely narrow width and a relatively long pulse interval during the current pulse-off period, so that the output voltage Vout1 of the DC-DC converter circuit 1 assumes the value 120 V, which is the set output voltage, during the current pulse-on period and becomes essentially 0 V during the current pulse-off period. Cause of the current pulse ripple

[0108] The following conclusions are drawn from the results of the first to third comparative examples. From the perspective of the constant current source (the DC-DC converter circuit 1 and the smoothing inductor 2), the load voltage of the pulse driver circuit 100 changes significantly and rapidly within the range of a predetermined voltage (for example, 120 V) to 0 V when the current pulse, the output current lout, is switched on and off. In this case, there is a mismatch between the energy output from the DC-DC converter circuit 1 and the energy consumed by the load (internal resistance of the constant current source or the load 32, hereinafter sometimes simply referred to as "load").If the mismatch is not resolved, the smoothing inductor 2 stores the energy corresponding to the mismatch and releases it to balance the energy output from the DC-DC converter circuit 1 and the energy consumed by the load. In the energy balancing function of the smoothing inductor 2, the inductor current II output from the DC-DC converter circuit 1 is smoothed, and the waveform of the smoothed inductor current II appears as a ripple in the current pulse, which is the output current lout.

[0109] If the feedback control of the inductor current II is implemented at the DC-DC converter circuit 1, as in the first to third comparative examples, the energy output from the DC-DC converter circuit 1 cannot quickly compensate for the energy consumed by the load due to the response delay of the inductor current II. The mismatch between the output energy and the energy consumed by the load must be resolved by the energy balancing function of the smoothing inductor 2. Therefore, the ripple of the current pulse cannot be significantly improved. Function and effect

[0110] The result of the above evaluation shows that if the load voltage changes rapidly due to switching the current pulse on and off, and the energy output from the DC-DC converter circuit 1 can quickly adapt to the energy consumed by the load, the function of the smoothing choke 2 is suppressed and the ripple of the current pulse is fundamentally improved.

[0111] The following conclusions are drawn from the results of the first and second examples.

[0112] In the disclosed pulse driver circuit 100, the feedback control of the inductor current II is carried out at the DC-DC converter circuit 1 during the current pulse on period. During the current pulse off period, the feedback control of the inductor voltage VI at the DC-DC converter circuit 1 is carried out.

[0113] Initially, during the transition from the current pulse on period to the current pulse off period in the feedback control, when the current pulse is switched off, the load voltage of the constant current source (the DC-DC converter circuit 1 and the smoothing inductor 2) assumes a value of 0 V. This is because the current pulse generation circuit 4 short-circuits between the second output end 3b and the first output end 3a, and the first output end 3a is connected to the low-potential output end 1a of the DC-DC converter circuit 1. Consequently, the output voltage Vout1 of the DC-DC converter circuit 1 is applied to the end of the smoothing inductor 2 on the DC-DC converter circuit 1 side, and the end on the load side essentially assumes a value of 0 V.In the feedback control of the inductor voltage VI, the target value Vlset of the inductor voltage is 0 V or a predetermined voltage close to 0 V. Therefore, in the DC-DC converter circuit 1, the feedback control reduces the output voltage Vout1 to 0 V or to a predetermined voltage close to 0 V, so that the inductor voltage VI becomes 0 V or a predetermined voltage close to 0 V. During this process, the DC-DC converter circuit 1 is controlled in such a way that the existing inductor current II is essentially maintained. This is because a change in the inductor current II would cause the induced voltage to create a potential difference at both ends of the smoothing inductor 2.Thus, in the DC-DC converter circuit 1, the output voltage Vout is feedback-controlled to a voltage of "essentially 0 V", a voltage required to keep the inductor current II essentially at the current value (the inductor current target value Ilset in feedback control of the inductor current). As a result, the energy output from the DC-DC converter circuit quickly adjusts to the energy consumed by the load (here by the internal resistance of the constant current source).

[0114] In the event of a transition from the current pulse off period to the current pulse on period in the feedback control, when the current pulse is switched on to adjust the load voltage to a predetermined voltage (for example, 120 V), the inductor current II of the DC-DC converter circuit increases rapidly. If feedback control of the inductor current II is performed at the DC-DC converter circuit 1 during the current pulse off period, the inductor current II of the DC-DC converter circuit 1 will be higher than the target inductor current value IIset at the end of the current pulse off period (see the first comparison example).At the time of a change to the current pulse-on period, the DC-DC converter circuit 1 is controlled by feedback to reduce the inductor current II until the inductor current II of the DC-DC converter circuit 1 becomes lower than the inductor current target value IIset, and therefore it is not possible to control the DC-DC converter circuit 1 by feedback in such a way that the inductor current II immediately assumes the inductor current target value Ilset.In contrast, in the disclosed pulse driver circuit 100, feedback control of the inductor voltage VI is performed at the DC-DC converter circuit 1 during the current pulse off period in order to control the inductor current II essentially to the inductor current target value Ilset, so that at the time of a change to the current pulse on period, the inductor current II detected by the inductor current sensor 5 is significantly reduced compared to the inductor current target value Ilset, and thus the DC-DC converter circuit 1 is directly controlled by feedback, so that the inductor current II assumes the inductor current target value Ilset. As a result, the energy output from the DC-DC converter circuit quickly adjusts to the energy consumed by the load.As described above, the power output from the DC-DC converter circuit 1 rapidly adjusts to the power consumed by the load during the current pulse off and on periods. Consequently, the effect of the smoothing inductor 2 is suppressed, fundamentally improving the current pulse ripple. In short, this is a unique invention that combines feedback control of the inductor voltage VI during the current pulse off period with feedback control of the inductor current II during the current pulse on period. This allows the power output from the DC-DC converter circuit 1 to rapidly adjust to the power consumed by the load, while the inductor current II is essentially maintained at the target value Ilset. As a result, the current pulse ripple is significantly improved. Further examples of implementation

[0115] In the above embodiment, the two-terminal voltage averaging circuit 8 can be omitted. Examples of this include the case where the averaged two-terminal inductor voltage Vla can be taken from the two-terminal inductor voltage sensor 7, the case where the detected two-terminal inductor voltage VI is smoothed (averaged) by the parasitic impedance of the two-terminal inductor voltage detection path from the two-terminal inductor voltage sensor 7 to the two-terminal inductor voltage control circuit 9, and the case where the detected two-terminal inductor voltage VI is smoothed (averaged) because the PWM signal has an extremely high carrier frequency.

[0116] In the above embodiment, a DC voltage generation circuit can be used instead of the DC voltage converter circuit 1, which generates a variable DC voltage not by PWM control, but by an analog circuit.

[0117] In the above embodiment, the throttle current target value Ilset can be stored at a different suitable location than the control device 33.

[0118] In the above embodiment, the pulse driver circuit 100 can include a control device with a processor and a memory, and the control device can output the pulse signal Spls and the choke current target value Ilset.

[0119] Experts will recognize numerous variations and further examples from the above description. Therefore, the above description should be understood as an example only.

[0120] The pulse driver circuit as disclosed can be used as a pulse driver circuit with which the ripple of the current pulse can be improved. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2016 / 167019

[0003]

Claims

[1] Pulse driver circuit (100) having the following features: a DC voltage generation circuit (1) that generates and outputs a DC voltage according to a reactor current command or a both-ended reactor voltage command selected by a command selection circuit; a smoothing reactor (2) having one end connected to a high-potential output end of the DC voltage generating circuit (1) and smoothing a reactor current output from the DC voltage generating circuit (1); an output end having a first output end and a second output end, the second output end being connected to another end of the smoothing reactor (2), the first output end being connected to a low-potential output end of the DC voltage generating circuit (1), and a load driven by a current pulse being connected between the second output end and the first output end; a current pulse generation circuit (4) that receives a pulse signal, which alternately comprises a current pulse off period and a current pulse on period, from the outside, short-circuits between the second output end and the first output end during the current pulse off period, and opens between the second output end and the first output end during the current pulse on period to generate the current pulse from the reactor current smoothed by the smoothing reactor (2), and outputs the current pulse to the load via the output end; a choke current sensor that detects the choke current; a throttle current control circuit (6) that outputs a throttle current command based on an error of the throttle current detected by the throttle current sensor with respect to a throttle current target value; a double-ended choke voltage sensor that detects a double-ended choke voltage of the smoothing choke (2); a both-ended choke voltage control circuit (9) that outputs a both-ended choke voltage command based on an error of a voltage derived from the both-ended choke voltage detected by the both-ended choke voltage sensor with respect to a voltage of 0 V as a target value of the both-ended choke voltage or a predetermined voltage close to 0 V; and the command selection circuit which receives the pulse signal from the outside, selects and outputs the reactor current command during the current pulse on period, and selects and outputs the both-ended reactor voltage command during the current pulse off period. [2] The pulse driving circuit (100) according to claim 1, wherein the voltage of 0 V or the predetermined voltage close to 0 V is a voltage in the range of 5% of a set output voltage of the DC voltage generating circuit (1). [3] Pulse driver circuit (100) according to claim 1 or 2, wherein the DC voltage generating circuit (1) is a DC-DC converter circuit (1) that generates and outputs a square-wave DC voltage, the square-wave DC voltage being controlled by pulse width modulation (PWM) control, from a DC voltage input from a DC power supply using one or more switching elements that are turned on and off according to one or more PWM signals, the smoothing choke (2) is a choke having one end connected to a high-potential output end of the DC-DC converter circuit and configured to smooth the choke current output from the DC-DC converter circuit, the first output end of the output end is connected to a low-potential output end of the DC-DC converter circuit, the current pulse generating circuit (4) receives the pulse signal from a control device, the inductor current control circuit (6) receives the inductor current target value from the control device and the command selection circuit receives the pulse signal from the control device, wherein the pulse driving circuit (100) comprises a PWM signal generating circuit that generates the one or more PWM signals corresponding to the one or more switching elements according to the inductor current command or the both-ended inductor voltage command from the command selecting circuit and outputs the one or more PWM signals to the one or more switching elements, respectively. [4] Pulse driver circuit (100) according to one of claims 1 to 3, further comprising a both-ended voltage averaging circuit which generates and outputs, as a voltage derived from a both-ended voltage of the smoothing reactor (2) detected by the both-ended reactor voltage sensor, a voltage obtained by averaging both-ended voltages of the smoothing reactor (2) detected by the both-ended reactor voltage sensor, wherein the both-ended choke voltage control circuit (9) is a circuit that outputs the both-ended choke voltage command based on an error of the voltage output from the both-ended voltage averaging circuit with respect to the target value of the both-ended voltage.

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