JP6984303B2 - Rush prevention circuit and rush prevention method - Google Patents

Description

The present invention relates to an intrusion prevention circuit using a non-contact switch and an intrusion prevention method.

Conventionally, in the fields of various plants and industrial equipment such as industrial robots, mechanical relays that move contacts by using magnetic force generated by an electromagnet or the like have been known. Mechanical relays are excellent in withstand voltage and noise resistance, while ensuring insulation between devices connected via movable contacts. Therefore, in the above field, for example, it may be used for controlling the continuity and opening of the feeding path connecting the power supply and the load.

When using a mechanical relay, an inrush prevention circuit composed of a CR integrator circuit or the like is installed side by side in the feeding path into which the mechanical relay is inserted for the purpose of suppressing chattering caused by mechanical vibration of the movable contact. May be done. By appropriately selecting the components (resistance value, capacitance value of the capacitor) constituting the inrush prevention circuit, the voltage fluctuation component in the frequency band defined by the CR time constant and the like can be suppressed.

The following patent documents exist as prior art documents that describe the techniques related to the techniques described in the present specification.

Japanese Unexamined Patent Publication No. 2005-347186

By the way, various power sources having different specification conditions such as voltage value, current value, and electric energy can be connected to the power supply path into which the mechanical relay is inserted. In the design of a power supply system that includes a mechanical relay in the power supply path, for example, the CR time constant of the CR integrator circuit is obtained for each of various power supplies with different specification conditions, and the parts to be used are selected based on the CR time constant and the number of parts is selected. , Parts placement, etc. were decided. In the above power supply system, new design of the inrush prevention circuit is repeated for each of various power supplies having different specification conditions, which may lead to a decrease in design efficiency.

Further, a motor or the like that generates an inrush current at the time of starting may be connected to the power feeding path as a load. The inrush current that flows from the power supply to the load side via the power supply path differs depending on the load rating. When a load that generates an inrush current is connected to the above power supply path, for example, as a countermeasure against inrush current, select a resistance type with high withstand power for each load rating, and use the selected resistance type to prevent inrush. The new design was done. Therefore, even when a load in which an inrush current is generated is connected, the design efficiency may be lowered.

The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a technique of an inrush prevention circuit capable of dealing with a variety of power supply specifications and load ratings.

In one example of the present disclosure, the following configuration was adopted.
That is, the inrush prevention circuit according to an example of the present disclosure is branched from the first power supply path and parallel to the first power supply path and the contact relay that controls the continuity and opening of the first power supply path connecting the power supply and the load. The non-contact relay that controls the continuity and opening of the second feeding path connected to the load, and the resistance value of the conduction period of the second feeding path and the second feeding path when the first feeding path of the contact relay is conducting. The second power supply is controlled by controlling at least one of the continuity period of the second power supply path, the repetition cycle of the continuity period of the second power supply path, the ratio between the continuity period and the open period of the second power supply path, and the current value of the continuity period of the second power supply path. It is characterized by comprising a non-contact relay control means for averaging the power of a power source branched into a path.

With the above configuration, the inrush prevention circuit according to the example of the present disclosure can time-division and average the electric power branched to the non-contact relay side. In the power supply system provided with the inrush prevention circuit, stable electric power can be supplied evenly with respect to the load connected to the inrush prevention circuit.

The non-contact relay of the inrush prevention circuit includes a switching element having a source into which the power of the power supply branched to the second feeding path is input and a drain connected to the load in parallel with the first feeding path. The control means conducts or opens between the source and drain of the switching element based on the gate voltage applied to the gate of the switching element, and even if the power of the power supply branched to the second feeding path is averaged. good.

With the above configuration, the inrush prevention circuit can control the gate voltage of the switching element to time-division and average the power of the power supply input to the source and output it to the drain. In the power supply system provided with the inrush prevention circuit, the averaged power value output to the drain of the switching element can be adopted as an index value at the time of design, so that improvement in design efficiency can be expected.

The control means of the inrush prevention circuit changes the voltage value of the gate voltage when conducting between the source and the drain of the switching element, and changes the voltage value of the second feeding path when the first feeding path of the contact relay is conducted. The resistance value during the conduction period may be controlled.

With the above configuration, the inrush prevention circuit can control the resistance value at the time of conduction of the second feeding path by varying the voltage value of the gate voltage. In the inrush prevention circuit, it can be shared as a circuit capable of corresponding to various CR time constants based on the resistance value at the time of conduction of the controlled second feeding path. Further, in the CR integrator circuit, the resistance can be reduced, and the board area on which the intrusion prevention circuit is mounted can be reduced.

The control means of the inrush prevention circuit changes at least one of the ratio of the gate voltage application period, the gate voltage application cycle interval, and the application period within the gate voltage application cycle interval according to the specification conditions of the power supply. , The voltage fluctuation accompanying the continuity of the first feeding path of the contact relay may be averaged to a predetermined voltage.

With the above configuration, the inrush prevention circuit can change the period width (pulse width) of the on period of the switching element, the cycle interval of the on period, the duty ratio, etc. according to the specification conditions of the power supply. The inrush prevention circuit can suppress the voltage value on which the voltage fluctuation waveform due to chattering of the mechanical relay is superimposed within the allowable range specified on the load side even when a power supply with various specification conditions is connected. ..

The control means of the inrush prevention circuit includes the gate voltage application period, the cycle interval in which the gate voltage is applied, the ratio of the application period within the cycle interval in which the gate voltage is applied, and the gate conducting between the source and drain of the switching element. At least one of the voltage values of the voltage may be varied according to the rating of the load to average the inrush current generated at the start of the load.

With the above configuration, the inrush prevention circuit can perform conduction (on) between the on-period period width (pulse width) of the switching element, the cycle interval of the on-period, the duty ratio, and the source / drain according to the load rating. The gate voltage value can be changed. The inrush prevention circuit can average the inrush current generated at the start of the load, even when loads of various ratings are connected. In a power supply system equipped with an inrush prevention circuit, it is possible to reduce the capacity (low withstand power) of the resistance device by selecting a resistance device that suppresses the inrush current based on the averaged current value.

Further, an example of the present disclosure includes a contact relay that controls the continuity and opening of the first power supply path that connects the power supply and the load, and a contact relay that branches from the first power supply path and connects to the load in parallel with the first power supply path. In an inrush prevention circuit having a non-contact relay that controls continuity and opening of the second power feeding path to be connected, and a control means connected to the non-contact relay, when the control means conducts the first feeding path of the contact relay. Controls at least one of the conduction period of the second feeding path, the repetition cycle of the conduction period of the second feeding path, the ratio between the conduction period of the second feeding path and the opening period, and the current value of the conduction period of the second feeding path. However, the inrush prevention method may be characterized in that a control step for averaging the power of the power supply branched to the second power feeding path is executed.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a technique of an inrush prevention circuit capable of dealing with a variety of power supply specifications and load ratings.

It is a figure explaining one form of the inrush prevention circuit. It is a figure which shows an example of the structure of the inrush prevention circuit which concerns on Embodiment 1. FIG. It is a figure explaining the operation of the inrush prevention circuit which concerns on Embodiment 1. FIG. It is a figure which shows an example of the structure of the inrush prevention circuit which concerns on Embodiment 2. It is a figure explaining the operation of the inrush prevention circuit which concerns on Embodiment 2. It is a figure which shows an example of the structure of the inrush prevention circuit which concerns on Embodiment 3. It is a figure explaining the operation of the inrush prevention circuit which concerns on Embodiment 3.

Hereinafter, the inrush prevention circuit according to the embodiment will be described with reference to the drawings.
[Application example]
The intrusion prevention circuit 10 according to the present embodiment includes a mechanical relay Z2 and a non-contact switch U1 arranged in parallel with the mechanical relay Z2, as illustrated in FIGS. 2, 4, and 6. In the inrush prevention circuit 10, the electric power supplied from the power sources (DC batteries B1 and B2) is branched and input to the mechanical relay Z2 and the non-contact switch U1. The electric power branched and input to each of the mechanical relay Z2 and the non-contact switch U1 is output to a load (not shown).
Here, the mechanical relay Z2 is an example of a "contact relay", and the non-contact switch U1 is an example of a "contactless relay". The power supply path between the power supply and the load connected via the mechanical relay Z2 is an example of the "first power supply path", and the power supply path between the power supply and the load connected via the non-contact switch U1 is the "second power supply path". This is an example of "power supply path".

The non-contact switch U1 has a switching element that conducts (on) and opens (off) the connection path between the source and drain by controlling the gate voltage (voltage value applied between the gate and the source). The gate voltage is controlled via the PWM control units 11, 12, and 13. The non-contact switch U1 conducts and opens between the source and drain via the gate voltage control of the PWM control units 11, 12, and 13, for example, to transfer the power of the power supply connected to the source of the switching element to the drain. Supply to the connected load side. Here, the PWM control units 11, 12, and 13 are examples of "control means".

The PWM control unit 11 controls the resistance value between the source and drain during conduction by controlling the voltage value applied between the gate and source of the non-contact switch U1. In the inrush prevention circuit 10, by controlling the resistance value between the source and drain, the non-contact switch U1 and the capacitor element C1 connected to the drain can be operated as a CR integrator circuit. The inrush prevention circuit can be shared as a circuit that can handle various CR time constants. In addition, the number of resistance devices can be reduced, and the board area on which the intrusion prevention circuit is mounted can be reduced.

The PWM control unit 12 controls the voltage value applied between the gate and the source of the switching element, and controls the pulse width of the non-contact switch U1 during the ON period, the cycle interval of the ON period, the duty ratio, and the like. In the voltage fluctuation period due to chattering of the mechanical relay Z2 or the like, for example, the amount of current flowing through the resistor R1 via between the source and drain conducted during the on period is limited, and the voltage value corresponding to the resistance value of the resistor R1 is set. It is output to the feeding path where one end of the capacitor element C1 and the other end of the movable contact of the mechanical relay Z2 are connected.

The PWM control unit 12 can handle power supplies having different specification conditions by varying the pulse width of the non-contact switch U1 during the on period, the cycle interval of the on period, the duty ratio, etc., according to the power supplies having different specification conditions. The intrusion prevention circuit 10 is provided.

The PWM control unit 13 controls the voltage value applied between the gate and the source of the switching element, and controls the pulse width of the non-contact switch U1 during the ON period, the cycle interval of the ON period, the duty ratio, and the like. Further, the PWM control unit 12 relatively increases or decreases the gate voltage value (voltage value applied between the gate and source) when conducting (on) between the source and drain, thereby causing the source and drain to be connected. Controls the value of the current flowing through.
During the inrush current period at the time of load start, the PWM control unit 13 limits the current value of the inrush current flowing between the source and drain of the non-contact switch U1 by the relative increase / decrease of the gate voltage value. Similarly, the amount of inrush current flowing between the source and drain is limited by the pulse width during the on period, the cycle interval during the on period, the duty ratio, and the like.

The PWM control unit 13 varies in rating by varying the pulse width of the non-contact switch U1 during the on period, the cycle interval of the on period, the duty ratio, the current value of the on period, and the like according to the loads having different ratings. An inrush prevention circuit 10 capable of handling a load is provided.

<1. Comparison form>
First, as a comparative form, an inrush prevention circuit installed side by side in a mechanical relay will be described.
FIG. 1 is a diagram illustrating a comparative form of intrusion prevention circuit. In FIG. 1, an inrush prevention circuit 100 composed of a diode element D101, a resistor R101, and a capacitor element C101 is exemplified. In FIG. 1, the DC battery B101 is a power source that supplies predetermined power (DC power) to the load side connected via the mechanical relay Z102. A fuse Z101 is inserted into the power supply path connecting the DC battery B101 and a load (not shown) for the purpose of protecting the overcurrent flowing into the load side in the event of a short circuit or failure.
A voltage supply terminal (positive electrode side terminal) of the DC battery B101 is connected to one end of the movable contact provided in the mechanical relay Z102, and a load (not shown) is connected to the other end of the movable contact. For the load connected to the other end of the movable contact of the mechanical relay Z102, for example, the electric power supplied from the DC battery B101 is supplied as a predetermined voltage value (VOUT). The mechanical relay Z102 has a drive unit for controlling the open / closed state of the movable contact by using a magnetic force generated by an electromagnet or the like, and a contact mechanism in which the open / closed state is controlled by the magnetic force or the like. The connection state between the DC battery B101 and the load is controlled by a binary status signal output to the drive unit. Here, the binary status signal is, for example, a voltage signal such as “High / Low” or “1/0”, and “High” or “1” is a high voltage value for generating a magnetic force when energized. Correspondingly, "Low" and "0" correspond to a low voltage value that does not generate a magnetic force. The connection state of the feeding path into which the mechanical relay Z102 is inserted is controlled by the state of the movable contact that is opened and closed according to the binary status signal.

In the inrush prevention circuit 100 of FIG. 1, the anode of the diode element D101 is connected to one end of the movable contact to which the voltage supply terminal side of the DC battery B101 of the mechanical relay Z102 is connected, and the cathode is connected to the input terminal of the resistor R101. To. The output end of the resistor R101 is connected to one end of the capacitor element C101 whose other end is grounded to the ground potential (GND). One end of the capacitor element C101 is connected to the other end of the movable contact of the mechanical relay Z102, and the other end of the capacitor element C101 is connected to the negative electrode side terminal of the DC battery B101.

The voltage fluctuation caused by chattering or the like of the mechanical relay Z102 is controlled by the diode element D101 to the voltage fluctuation in a certain direction. Further, the pass band of the frequency band of voltage fluctuation is limited by the CR time constant defined by the resistance value of the resistor R101 and the capacitance value of the capacitor element C101. The voltage change width due to the voltage fluctuation is limited to the change width defined by the resistance value of the resistor R101 and the capacitance value of the capacitor element C101. For the load connected to the power supply path in which the inrush prevention circuit 100 is arranged side by side, for example, the power overlaid with the voltage waveform blunted by limiting the pass band and the voltage change width by the CR time constant is a predetermined voltage value ( It is output as VOUT). A predetermined voltage value (VOUT) controlled within an allowable range is supplied to the load side connected to the feeding path in which the inrush prevention circuit 100 is arranged side by side.

In the inrush prevention circuit 100 of FIG. 1, for example, according to different specification conditions such as voltage value, current value, and electric energy of the power supply (DC battery B101) connected to one end of the movable contact provided in the mechanical relay Z102. The resistance value of the resistor R101 and the capacitance value of the capacitor element C101 were determined. In particular, the resistance value of the resistor R101 and the number of resistance devices constituting the resistor R101 are different for each specification condition of the power supply so that the predetermined voltage value (VOUT) supplied to the load side is within the allowable range of the load side. It was designed. Therefore, in the design of the power feeding system using the mechanical relay, there is a risk that the design efficiency may be lowered.

<2. Embodiment>
(Embodiment 1)
FIG. 2 is a diagram showing an example of the configuration of the inrush prevention circuit according to the first embodiment (hereinafter, also referred to as the present embodiment). In FIG. 2, a power supply system 1 including the inrush prevention circuit 10 according to the present embodiment is exemplified. In the power supply system 1 of FIG. 2, the electric power supplied from the DC battery B1 is supplied as a predetermined voltage value (VOUT) to the load side (not shown) via the inrush prevention circuit 10 inserted in the power supply path.
However, in the power feeding system 1 including the inrush prevention circuit 10 of the present embodiment, the resistor R101 of the CR integrator circuit (resistor R101, capacitor element C101) exemplified in FIG. 1 is not required. In FIG. 2, the capacitor element C1 and the fuse Z1 correspond to the capacitor element C101 and the fuse Z101 exemplified in FIG. 1, respectively.

As shown in FIG. 2, the inrush prevention circuit 10 includes a mechanical relay Z2 in the configuration. The mechanical relay Z2 corresponds to the mechanical relay Z102 illustrated in FIG. However, the inrush prevention circuit 10 according to the present embodiment includes a non-contact switch U1 juxtaposed with the mechanical relay Z2 in the configuration. In FIG. 2, a semiconductor relay (SSR: Solid State Relay) is exemplified as the non-contact switch U1. A semiconductor relay is a relay including a switching element composed of semiconductor devices such as a thyristor, a triac, and a transistor, and is a relay (non-contact relay) that does not have a movable contact mechanism like a mechanical relay. However, the non-contact switch U1 juxtaposed with the mechanical relay Z2 may be composed of a semiconductor device such as a transistor. The non-contact switch U1 shown in FIG. 2 is an example including a semiconductor switching element composed of a P-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).

In FIG. 2, the voltage supply terminal (positive electrode side terminal) of the DC battery B1 is connected to one end of the movable contact of the mechanical relay Z2 of the inrush prevention circuit 10 via the fuse Z1. The other end of the movable contact of the mechanical relay Z2 is connected to a load (not shown).

The voltage supply terminal (positive electrode side terminal) of the DC battery B1 is connected to the source of the non-contact switch U1 of the inrush prevention circuit 10 via the fuse Z1. Further, the input terminal of the capacitor element C1 is connected to the drain of the non-contact switch U1. The gate of the non-contact switch U1 is connected to the PWM (Pulse Width Modulation) control unit 11. The PWM control unit 11 is a control device that controls a voltage value or the like applied to the gate of the non-contact switch U1. As the PWM control unit 11, for example, a microcomputer or the like is exemplified. The PWM control unit 11 may include a memory, a DA converter, and the like.

In the P-type MOSFET constituting the non-contact switch U1, for example, when the voltage between the gate and the source is equal to or less than the threshold voltage (Vth), the source and drain are conducted (on). Further, when the voltage between the gate and the source exceeds the threshold voltage (Vth), the source and the drain are opened (off). The control of the voltage between the gate and the source is performed, for example, via the PWM control unit 11.
In the following, the non-contact switch U1 will be described as a P-type MOSFET, but even if it is an N-type, the same effect can be obtained. That is, in the N-type, when the voltage between the gate and the source is equal to or higher than the threshold voltage (Vth), the source and drain are conducted (on), and when the voltage is lower than the threshold voltage (Vth), the source and drain are opened (between the source and drain). Off).

In the inrush prevention circuit 10 according to the present embodiment, the PWM control unit 11 controls the voltage value applied between the gate and source of the non-contact switch U1 to control the resistance value between the source and drain during conduction. Control. In the inrush prevention circuit 10, by controlling the resistance value between the source and drain, the non-contact switch U1 and the capacitor element C1 connected to the drain can be operated as a CR integrator circuit. In the power supply system 1, circuits including the inrush prevention circuit 10 can be standardized. As compared with the inrush prevention circuit 100 illustrated in FIG. 1, the resistance device constituting the CR integrator circuit can be deleted. Therefore, in the power feeding system 1 including the inrush prevention circuit 10 according to the present embodiment, the relative cost of members can be relatively suppressed. By removing the resistance device, for example, it becomes possible to reduce the relative size of the board area on which the power feeding system 1 is mounted.

FIG. 3 is a diagram illustrating the operation of the inrush prevention circuit 10 according to the present embodiment. The graph illustrated in FIG. 3 shows the gate voltage (applied voltage between the gate and source) characteristics of the non-contact switch U1 according to the present embodiment. The vertical axis of FIG. 3 represents the resistance value between the source and drain during conduction, and the horizontal axis represents the voltage value applied between the gate and source. “Vref” represents a reference voltage (threshold voltage) for switching between conduction and opening between the source and drain of the non-contact switch U1.

As shown in FIG. 3, the non-contact switch U1 has a region E1 (ohm region) in which the resistance value linearly decreases in proportion to the increase in the gate voltage when a constant drain voltage is applied. In the case of N-type MOSFET, the graph illustrated in FIG. 3 has the opposite characteristics. That is, the ohm region is a region in which the resistance value linearly increases in proportion to the increase in the gate voltage.

The PWM control unit 11 of the inrush prevention circuit 10 according to the present embodiment controls the voltage value applied between the gate and the source in the region E1 surrounded by the broken line in FIG. Controls the resistance value of. In the power supply system 1 including the inrush prevention circuit 10, the resistance value specified by the voltage value applied between the gate and the source and the capacitance value of the capacitor element C1 connected to the drain of the non-contact switch U1 are used for CR. It becomes possible to change the constant.

The characteristics of the gate voltage and the resistance value between the source and drain in the region E1 can be obtained experimentally in advance. The provider (manufacturer) of the inrush prevention circuit 10 can measure the above characteristics with respect to the non-contact switch U1 and store the measurement result in the memory or the like of the PWM control unit 11 as a parameter of the gate control. The reading of the table value stored in the memory or the like is, for example, a DIP (Dual Inline Package) on a board on which the inrush prevention circuit 10 is mounted.
) It is performed according to the indicated value set via a switch or the like. The PWM control unit 11 of the inrush prevention circuit 10 reads out the parameter value specified by the above indicated value, and can control the gate of the non-contact switch U1.

As described above, the inrush prevention circuit 10 includes a PWM control unit 11 that controls the resistance value between the source and drain of the non-contact switch U1 at the time of conduction by the gate voltage. In the inrush prevention circuit 10, by controlling the resistance value between the source and drain, the non-contact switch U1 and the capacitor element C1 connected to the drain can be operated as a CR integrator circuit. According to the intrusion prevention circuit 10 of the present embodiment, there is provided a technique of an intrusion prevention circuit capable of dealing with various CR time constants by the resistance value between the source and drain of the non-contact switch U1 and the capacitor element C1 connected to the drain. can.

(Embodiment 2)
FIG. 4 is a diagram showing an example of the configuration of the inrush prevention circuit according to the second embodiment (hereinafter, also referred to as the present embodiment). In FIG. 4, as in FIG. 2, the power supply system 1 including the intrusion prevention circuit 10 according to the present embodiment is exemplified. In the power supply system 1 of FIG. 4, the electric power supplied from the DC battery B1 is supplied as a predetermined voltage value (VOUT) to the load side (not shown) via the inrush prevention circuit 10 inserted in the power supply path.
However, the specifications of the DC battery B1 are various, and various voltage values, current values, electric powers, etc. based on the specifications are supplied from the DC battery B1 to the load side. In FIG. 4, the resistor R1, the capacitor element C1, and the fuse Z1 correspond to the resistor R101, the capacitor element C101, and the fuse Z101 exemplified in FIG. 1, respectively.

Similar to the first embodiment, the intrusion prevention circuit 10 of the present embodiment includes the mechanical relay Z2 corresponding to the mechanical relay Z102 exemplified in FIG. 1 in the configuration. Further, the inrush prevention circuit 10 includes a non-contact switch U1 juxtaposed with the mechanical relay Z2 in the configuration. The non-contact switch U1 is the same as that of the first embodiment. The voltage supply terminal (positive electrode side terminal) of the DC battery B1 in FIG. 4 is connected to one end of the movable contact of the mechanical relay Z2 of the inrush prevention circuit 10 via the fuse Z1. The other end of the movable contact of the mechanical relay Z2 is connected to a load (not shown).

Similar to the first embodiment, the voltage supply terminal (positive electrode side terminal) of the DC battery B1 is connected to the source of the non-contact switch U1 of the inrush prevention circuit 10 via the fuse Z1. Further, an input terminal of the resistor R1 is connected to the drain of the non-contact switch U1. The gate of the non-contact switch U1 is connected to the PWM control unit 12. The PWM control unit 12 is a control device that controls a voltage value or the like applied to the gate of the non-contact switch U1, and is, for example, a microcomputer or the like. The PWM control unit 12 may include a memory, a DA converter, or the like.

Similar to the first embodiment, the non-contact switch U1 is conducted (on) between the source and the drain when the voltage between the gate and the source is equal to or less than the threshold voltage (Vth). Further, when the voltage between the gate and the source exceeds the threshold voltage (Vth), the source and the drain are opened (off). The control of the voltage between the gate and the source is performed via the PWM control unit 12.

The PWM control unit 12 controls the on period and the off period of the non-contact switch U1 by controlling the voltage value applied between the gate and the source of the switching element of the non-contact switch U1, for example. By controlling the on period and the off period of the non-contact switch U1, for example, the amount of current flowing through the resistor R1 via the source and drain conducted during the on period is limited, and the voltage value corresponding to the resistance value of the resistor R1 is set. , It is output to the power feeding path where one end of the capacitor element C1 and the other end of the movable contact of the mechanical relay Z2 are connected.

The intrusion prevention circuit 10 according to the present embodiment is, for example, variable in terms of the period width (pulse width) of the non-contact switch U1 during the on period, the cycle interval of the on period, the duty ratio, etc., in accordance with the specifications of the DC battery B1. Control. Here, the period width (pulse width) of the on period, the cycle interval of the on period, the duty ratio, and the like are controlled by, for example, a PWM method. However, the period width (pulse width) of the on period, the cycle interval of the on period, the duty ratio, and the like may be controlled by a PFM (Pulse-Frequency Modulation) method, a PAM (Pulse Amplitude Modulation) method, or the like.

In the inrush prevention circuit 10, the voltage value output to the power supply path via the resistor R1 is controlled by controlling the time-divisioned current amount during the on period of the non-contact switch U1 according to the specifications of the DC battery B1. It is controlled to be within a certain range. In the inrush prevention circuit 10 according to the present embodiment, even when a DC battery B1 having various specifications is connected, a predetermined voltage value (VOUT) on which a voltage fluctuation waveform due to chattering of the mechanical relay Z2 or the like is superimposed is obtained. It becomes possible to suppress within the allowable range specified on the load side.

FIG. 5 is a diagram illustrating the operation of the intrusion prevention circuit 10 of the present embodiment. In FIG. 5, (1) represents the output of the non-contact switch U1, and (2) represents the output after a period in which voltage fluctuations such as chattering of the mechanical relay Z2 occur. The vertical axis of FIG. 5 represents a voltage value, and the horizontal axis represents time.

In the inrush prevention circuit 10, the PWM control unit 12 connected to the gate of the non-contact switch U1 is, for example, the gate of the non-contact switch U1 triggered by a change in the status of a control signal for controlling the open / closed state of the movable contact of the mechanical relay Z2. Control is started (ts). For example, in the mechanical relay Z2, the contact state changes from the closed state to the open state as the control signal status changes from “High” to “Low”, and the control signal status changes from “Low” to “High”. With the change, the contact state changes from the open state to the closed state. When the contact state is closed, the feeding path into which the mechanical relay Z2 is inserted conducts, and when the contact state is open, the feeding path is opened.

In FIGS. 5 (1) and 5 (2), the PWM control unit 12 does not have a control signal for controlling the open / closed state of the movable contact of the mechanical relay Z2, for example, triggered by a change from “Low” to “High”. The gate control of the switching element of the contact switch U1 is started. A current due to voltage fluctuations such as chattering caused by the mechanical relay Z2 flows into the source of the switching element. The PWM control unit 12 controls the voltage value applied between the gate and the source of the switching element, and controls the pulse width of the non-contact switch U1 during the ON period, the cycle interval of the ON period, the duty ratio, and the like. The amount of current flowing between the source and drain of the non-contact switch U1 is limited by the pulse width during the ON period.

As shown in FIG. 5 (1), during a period in which voltage fluctuations such as chattering occur, a source current flows between the source and drain conducted by the gate control of the PWM control unit 12, and the conduction period between the source and drain is reached. Correspondingly, the source current is time-divisioned. A voltage change with a pulsed waveform according to the amount of time-divisioned source current is output to the feeding path via the resistor R1 connected to the drain of the switching element. During the period when the voltage fluctuation such as chattering continues, the gate control by the PWM control unit 12 continues, and the voltage fluctuation caused by the chattering or the like is averaged.

As shown in FIG. 5 (2), after a period of voltage fluctuation such as chattering elapses, the electric power supplied from the DC battery B1 is set as a predetermined voltage to the power supply path connected via the movable contact of the mechanical relay Z2. Applied. The load connected to the power supply path in which the non-contact switches U1 are arranged side by side includes power such as chattering that is gate-controlled and averaged via the PWM control unit 12 shown in FIG. 5 (1), and FIG. The electric power shown in (2) is supplied as a predetermined voltage value (VOUT) controlled within an allowable range.

The gate control of the PWM control unit 12 corresponding to the specifications of the DC battery B1 can be specified in advance by using, for example, an experimentally connected DC battery B1 having different specifications, a mechanical relay Z2, a load, or the like. be.
The provider (manufacturer) of the inrush prevention circuit 10 opens and closes the movable contact of the mechanical relay Z2 in the power supply path to which the DC battery B1, the mechanical relay Z2, the load, etc. are connected, and chattering occurs at the time of opening and closing. The electrical characteristics such as are measured for each DC battery B1 having different specifications. The measured electrical characteristics are, for example, a voltage fluctuation period due to chattering or the like, a voltage fluctuation width, an attenuation tendency at the time of voltage fluctuation, and the like.
The provider (manufacturer) of the inrush prevention circuit 10 or the like determines the gate control parameter (ON) so that the voltage value (VOUT) within the allowable range is obtained from the electrical characteristics measured for each DC battery B1 having different specifications. Specify the pulse width of the period, the cycle interval of the on period, the duty ratio, etc.). However, for the gate control parameters, for example, the specification range of the DC battery B1 (for example, the voltage range from ** VDC to \\ VDC) is divided in stages, and the gate control parameters are associated with each divided stage. May be. In the inrush prevention circuit 10, it is possible to obtain a gate control parameter that averages and suppresses voltage fluctuations caused by chattering or the like based on data measured experimentally in advance.

The provider (manufacturer) of the inrush prevention circuit 10 stores the specified gate control parameters in the memory or the like of the PWM control unit 12 as a parameter table associated with the specifications of the DC battery B1, for example. can do. The reading of the table value stored in the memory or the like is performed by, for example, the indicated value set via the DIP (Dual Inline Package) switch or the like on the board on which the inrush prevention circuit 10 is mounted. When the inrush prevention circuit 10 is used, the PWM control unit 12 reads out the parameter value associated with the specification condition of the DC battery B1 specified by the above indicated value, and enables the gate control of the non-contact switch U1.

As described above, the non-contact switch U1 of the inrush prevention circuit 10 includes a PWM control unit 12 that controls the gate of the switching element, and the voltage of chattering or the like of the mechanical relay Z2 arranged side by side based on the gate control. The current due to fluctuations can be time-divided and averaged. The PWM control unit 12 has parameters (pulse width during on period, cycle interval during on period, duty) related to gate control of the non-contact switch U1 according to a power source (DC battery B1) with different specification conditions connected to the power supply path. Ratio etc.) can be changed. According to the inrush prevention circuit 10 of the present embodiment, there is provided a technique of an inrush prevention circuit capable of supporting power supplies having different specification conditions.

Even if the non-contact switch U1 of the second embodiment is an N type, the above effect can be obtained. In the N type, when the voltage between the gate and source is equal to or higher than the threshold voltage (Vth), the source and drain are conducted (on), and when the voltage is lower than the threshold voltage (Vth), the source and drain are opened (off). Will be done. The PWM control unit 12 may control the non-contact switch U1 by varying the period width (pulse width) of the on period, the cycle interval of the on period, the duty ratio, and the like in accordance with voltage fluctuations such as chattering.

Further, the non-contact switch U1 may be at least a circuit or device that time-divides and averages the current due to voltage fluctuations such as chattering of the mechanical relays Z2 arranged side by side. The non-contact switch U1 is provided with, for example, an input terminal corresponding to a source, an output terminal corresponding to a drain, and a control terminal corresponding to a gate, and has an on period of the non-contact switch U1 according to a voltage value applied to the control terminal. The period width (pulse width), the cycle interval of the on period, the duty ratio, and the like may be variably controlled.

(Embodiment 3)
In the inrush prevention circuit 100 of FIG. 1, for example, an electric motor load such as a motor and a lamp load such as an incandescent light bulb may be connected to a power feeding path into which the mechanical relay Z102 is inserted. When the load is connected, the inrush current generated at the start of the load may flow in the feeding path. When the inrush current flows in the feeding path, the resistance device is selected in consideration of the maximum value of the inrush current and the like. For example, as the resistor R101 shown in FIG. 1, a cement resistor having high power resistance, which has improved heat resistance by adopting an enamel or the like for protecting the resistor on the outer skin, corresponds to the maximum value of the inrush current for each load. It was selected. Therefore, in the design of the power supply system using the mechanical relay when the load that generates the inrush current is connected, there is a possibility that the design efficiency may be lowered. In addition, cement resistance has a high component cost, and when the maximum value of the inrush current is relatively high, it has been a factor in increasing the cost of the power supply system using the mechanical relay.

In the inrush prevention circuit according to the third embodiment (hereinafter, also referred to as the present embodiment), as in the second embodiment, by controlling the gate of the non-contact switch U1 juxtaposed to the mechanical relay, the resistance device can be used. The inrush current that flows is time-divisioned and averaged. The averaging of the inrush current is performed according to the inrush current characteristics (maximum current value, duration, etc.) for each load. In the inrush prevention circuit, by averaging the inrush current, for example, it is possible to reduce the capacity (low withstand power) of the resistance device.

FIG. 6 is a diagram showing an example of the configuration of the inrush prevention circuit according to the present embodiment. In FIG. 6, the power supply system 1 including the inrush prevention circuit 10 according to the present embodiment is exemplified. In the power supply system 1 of FIG. 6, the electric power of the DC battery B2 is supplied as a predetermined voltage value (VOUT) to the load side (not shown) via the inrush prevention circuit 10 inserted in the power supply path. However, the load connected to the power feeding path is a load in which an inrush current is generated when the power is turned on, and the characteristics of the inrush current (maximum current value, duration, etc.) differ for each load. The resistor R2 exemplified in FIG. 6 functions to suppress the maximum value (peak value) of the inrush current as described above, and the capacitor element C2 suppresses high frequency noise of the power supplied to the load via the feeding path. It works to suppress. The fuse Z1 corresponds to the fuse Z101 exemplified in FIG.

As shown in FIG. 6, the inrush prevention circuit 10 includes a mechanical relay Z2 and a non-contact switch U1 juxtaposed to the mechanical relay Z2 in the configuration. The mechanical relay Z2 and the non-contact switch U1 are the same as those in the second embodiment. The voltage supply terminal (positive electrode side terminal) of the DC battery B2 of FIG. 6 is connected to one end of the movable contact of the mechanical relay Z2 of the inrush prevention circuit 10 via the fuse Z1. The other end of the movable contact of the mechanical relay Z2 is connected to a load (not shown).

Further, the voltage supply terminal (positive electrode side terminal) of the DC battery B2 is connected to the source of the non-contact switch U1 via the fuse Z1, and the input terminal of the resistor R2 is connected to the drain of the non-contact switch U1. The gate of the non-contact switch U1 is connected to the PWM control unit 13. The PWM control unit 13 is a control device that controls a voltage value or the like applied to the gate of the non-contact switch U1, and is, for example, a microcomputer or the like. The PWM control unit 13 may include a memory, a DA converter, and the like.

Similar to the second embodiment, in the P-type MOSFET constituting the non-contact switch U1, for example, when the voltage between the gate and the source is equal to or less than the threshold voltage (Vth), the source and drain are conducted (on). To. Further, when the voltage between the gate and the source exceeds the threshold voltage (Vth), the source and the drain are opened (off). During conduction (on) between the source and drain, the current flowing between the source and drain depends on the voltage value applied between the gate and source. The control of the voltage value applied between the gate and the source is performed, for example, via the PWM control unit 13.

In the inrush prevention circuit 10 according to the present embodiment, the PWM control unit 13 controls the voltage value applied between the gate and the source of the switching element of the non-contact switch U1 and the period width of the on period of the non-contact switch U1. , The cycle interval of the on period, the duty ratio, etc. are controlled. Further, the PWM control unit 13 relatively increases or decreases the gate voltage value (voltage value applied between the gate and source) when conducting (on) between the source and drain, so that the source and drain are connected. Controls the value of the current flowing through.

FIG. 7 is a diagram illustrating the operation of the intrusion prevention circuit 10 of the present embodiment. In FIG. 7, “Ioc” represents the time transition of the inrush current generated at the start of a load such as a motor, and “Iave” represents the time transition of the averaged inrush current. “T1” represents the time when the load is started. The graph g1 represents an example of control of the voltage value applied between the gate and the source by the PWM control unit 12. The vertical axis of FIG. 7 represents the relative magnitudes of the illustrated “Ioc”, “Iave”, and voltage values, and the horizontal axis represents time. In the graph g1, a control mode for controlling the period width of the non-contact switch U1 during the on period, the cycle interval of the on period, and the current value flowing between the source and drain is exemplified.

An inrush current having a plurality of peaks (P1, P2, P3, P4) shown in “Ioc” of FIG. 7 flows into the source of the non-contact switch U1 illustrated in FIG. 6 at the start of the load. The peak current value of each peak decreases with the passage of time. The PWM control unit 13 starts control of the voltage value applied between the gate and the source shown in the graph g1 of FIG. 7, for example, triggered by the start of the load. The start of the load is notified to the PWM control unit 13, for example, from the connected load side or a higher-level control device that controls the equipment including the power supply system 1.

As shown in the graph g1 of FIG. 7, the PWM control unit 13 gates, for example, a pulsed gate voltage g1a in which the voltage value is relatively reduced during the inrush current period of the peak P1 at which the current value is maximized. Apply between sources to conduct between source and drain. During the conduction period, the current value of the inrush current with the peak P1 flowing between the source and drain of the non-contact switch U1 is limited to the current value defined by the relatively reduced gate voltage value. The amount of inrush current flowing between the source and drain of the non-contact switch U1 at the peak P1 is limited by the pulse width of the gate voltage g1a.

In the next peak P2 inrush current period, the PWM control unit 13 applies, for example, a pulsed gate voltage g1b whose voltage value is relatively larger than the gate voltage g1a between the gate and the source, and between the source and the drain. To conduct. In the conduction period, the current value of the inrush current with the peak P2 flowing between the source and drain is limited to the current value defined by the gate voltage value of the gate voltage g1b, as in the case of applying the gate voltage g1a. Further, the amount of inrush current flowing between the source and drain of the non-contact switch U1 at the peak P2 is limited by the pulse width of the gate voltage g1b.

As shown in the graph g1 of FIG. 7, control by the gate voltages g1c and g1d is performed in the same manner as above during the inrush current period of the peaks P3 and P4. The current value and amount of the inrush current with each peak flowing between the source and drain during the conduction period are limited by the voltage values of the gate voltages g1c and g1d and the pulse width.
In the graph g1 of FIG. 7, the gate voltage g1c is controlled so that the voltage value is relatively higher than the gate voltage g1b, and the gate voltage g1d is controlled to be relatively lower than the gate voltage g1c. Further, the application period (pulse width) of the gate voltage g1c and the gate voltage g1d.
Is controlled to be relatively longer than the application period of the gate voltages g1a and g1b.

As illustrated in FIG. 7, the PWM control unit 13 changes the parameters for controlling the gate voltage according to the characteristics of the inrush current (duration, time transition of current value, peak value, etc.). As a result, in the inrush prevention circuit 10 according to the present embodiment, the inrush current flowing in at the start of the load is time-divisioned via the gate voltage control of the PWM control unit 13. Time-division inrush currents are averaged as shown in "Iave" in FIG.

The gate control of the PWM control unit 13 corresponding to the rating different for each load can be experimentally obtained in advance in the same manner as in the second embodiment. The provider (manufacturer) of the inrush prevention circuit 10 measures, for example, the current characteristics of the inrush current generated at the time of starting in each power supply path to which the DC battery B1, the mechanical relay Z2, the load, etc. are connected for each load rating. do. Examples of the current characteristics of the inrush current include the duration of the inrush current, the time transition of the current value, the peak current value, and the like.
The provider (manufacturer) of the inrush prevention circuit 10 or the like has a gate so that the inrush current is averaged according to the low power resistance resistance device from the current characteristics of the inrush current measured for each load having different ratings. Identify control parameters. Examples of the gate control parameters include a pulse width during the on period, a cycle interval during the on period, a duty ratio, and a gate voltage value at the time of on.
The current characteristics of the measured inrush current may be divided into a plurality of groups, and the gate control parameters may be associated with each of the divided groups. Further, load groups having different ratings may be associated with each divided group.

The provider (manufacturer) or the like of the inrush prevention circuit 10 stores the specified gate control parameters in the memory or the like of the PWM control unit 13 as a parameter table associated with, for example, a load group having a different rating. Can be done. The reading of the table value stored in the memory or the like is performed by, for example, the indicated value set via the DIP switch or the like on the board on which the inrush prevention circuit 10 is mounted. When the inrush prevention circuit 10 is used, the PWM control unit 13 can read out the parameter value associated with the load group or the like specified by the above indicated value and control the gate of the non-contact switch U1.

As described above, according to the inrush prevention circuit of the present embodiment, the inrush current that differs for each load can be time-divided according to the low withstand power resistance device, so that when a load that generates an inrush current is connected. Even so, it is possible to improve the design efficiency of the power supply system using the mechanical relay. In addition, since a low power resistance resistance device can be adopted, the cost of parts can be suppressed, and the cost of a power supply system using a mechanical relay can be expected to be reduced. According to the intrusion prevention circuit 10 of the present embodiment, a technique of an intrusion prevention circuit capable of dealing with a variety of load ratings is provided.

Even if the non-contact switch U1 of the present embodiment is an N type, the above effect can be obtained. That is, in the N-type, when the voltage between the gate and the source is equal to or higher than the threshold voltage (Vth), the source and drain are conducted (on), and when the voltage is lower than the threshold voltage (Vth), the source and drain are opened (between the source and drain). Off). During conduction (on) between the source and drain, the current flowing between the source and drain depends on the voltage value applied between the gate and source. The PWM control unit 13 changes the parameters for controlling the gate voltage according to the characteristics of the inrush current (duration, time transition of current value, peak value, etc.), and has a period width of the on period, a cycle interval of the on period, and the like. The duty ratio and the current value flowing between the source and drain during the on period may be controlled.

Further, the non-contact switch U1 according to the present embodiment may be at least a circuit, a device, or the like that time-divisions and averages the inrush current flowing through the resistance device. The non-contact switch U1 is provided with, for example, an input terminal corresponding to a source, an output terminal corresponding to a drain, and a control terminal corresponding to a gate, and has an on period of the non-contact switch U1 according to a voltage value applied to the control terminal. The period width (pulse width), the cycle interval of the on period, the duty ratio, the current value flowing during the on period, and the like may be variably controlled.

<3. Deformation form>
The processes of the inrush prevention circuit 10 described in the second and third embodiments can be used in combination. In the PWM control unit of the intrusion prevention circuit 10 in the modified form, for example, a gate control parameter table associated with the specifications of the DC battery B1 and a parameter table associated with load groups having different ratings are stored in a memory or the like. Just do it. In the modified form of the inrush prevention circuit 10, the processing functions described in the second and third embodiments can be provided according to the power supply specifications and the load rating. In the modified form of the inrush prevention circuit 10, the resistors R1 and R2 connected to the drain of the non-contact switch U1 can be replaced with a low power resistance device having the same resistance value.

[Form example]
The inrush prevention circuit (10) according to an example of the present disclosure is
A contact relay (Z2) that controls the continuity and opening of the first power supply path that connects the power supply (B1, B2) and the load, and
A non-contact relay (U1) that branches from the first feeding path and controls the continuity and opening of the second feeding path connected to the load in parallel with the first feeding path.
When the contact relay (Z2) conducts the first feeding path, the resistance value of the conduction period of the second feeding path, the conduction period of the second feeding path, and the repeating cycle of the conduction period of the second feeding path. The ratio of the conduction period to the open period of the second power supply path and at least one of the current values of the continuity period of the second power supply path are controlled, and the power of the power supply branched to the second power supply path is averaged. The control means (11, 12, 13) of the non-contact relay (U1) and
It is characterized by having.

The above-described configurations of the embodiment and the modified form are exemplary, and the intrusion prevention circuit is not limited to the configurations of the embodiment and the modified form. The intrusion prevention circuit may be appropriately modified and implemented without departing from the gist of the present disclosure. The characteristic configurations shown in the embodiments and modifications can be freely combined and implemented as long as technical inconsistencies do not occur.

1 Power supply system 10,100 Rush prevention circuit 11,12,13 PWM control unit B1, B2, B101 DC battery C1, C2, C101 Condenser element D101 Diode element R1, R2, R101 Resistance U1 Non-contact switch (contactless relay)
Z1, Z101 Fuse Z2, Z102 Mechanical Relay

Claims (6)

A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and load,
Parallel to the first power supply path with a source to which the power of the power source branched from the first power supply path and branched to the second power supply path connected to the load in parallel with the first power supply path is input. With a switching element having a drain connected to the load,
The voltage value of the gate voltage when conducting between the source and the drain of the switching element is variable, and the conduction of the second feeding path is made according to the current after the conduction of the first feeding path of the contact relay. by controlling the resistance value of the period, and control means for averaging the power of the power source is branched into the second feed path,
A rush prevention circuit characterized by being equipped with. A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and load,
Parallel to the first power supply path with a source to which the power of the power source branched from the first power supply path and branched to the second power supply path connected to the load in parallel with the first power supply path is input. With a switching element having a drain connected to the load,
The application period of the gate voltage of the switching element, the periodic interval of applying the gate voltage, variable and in accordance with at least one of the ratio of the application period of the periodic interval for applying the gate voltage to the specification conditions of the power supply, the By controlling the resistance value of the conduction period of the second feeding path according to the current after conduction of the first feeding path of the contact relay, the power of the power supply branched to the second feeding path is averaged. However, control means for averaging the predetermined voltage a voltage variation caused at the time of conduction of the first power supply path of the reed relay,
A rush prevention circuit characterized by being equipped with. A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and load,
Parallel to the first power supply path with a source to which the power of the power source branched from the first power supply path and branched to the second power supply path connected to the load in parallel with the first power supply path is input. With a switching element having a drain connected to the load,
The application period of the gate voltage of the switching element, the cycle interval in which the gate voltage is applied, the ratio of the application period within the cycle interval in which the gate voltage is applied, and the gate voltage conducting between the source and drain of the switching element. At least one of the voltage values of the above is variable according to the rating of the load, and the resistance value of the conduction period of the second feeding path is controlled according to the current after conduction of the first feeding path of the contact relay. By doing so, the electric current branched to the second power supply path
The power source is averaged, and the average that control means turn into a rush current occurring at the start of the load,
A rush prevention circuit characterized by being equipped with. A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and the load, and a second power supply that branches from the first power supply path and is connected to the load in parallel with the first power supply path. In an inrush prevention circuit having a switching element having a source into which the power of the power source branched into the path is input, a drain connected to the load in parallel with the first feeding path, and a control means.
The control means
The voltage value of the gate voltage when conducting between the source and the drain of the switching element is variable, and the conduction of the second feeding path is made according to the current after the conduction of the first feeding path of the contact relay. by controlling the resistance value of the period, the control step of averaging the power of the power source is branched into the second feed path,
A rush prevention method characterized by performing. A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and the load, and a second power supply that branches from the first power supply path and is connected to the load in parallel with the first power supply path. In an inrush prevention circuit having a switching element having a source into which the power of the power source branched into the path is input, a drain connected to the load in parallel with the first feeding path, and a control means.
The control means
The application period of the gate voltage of the switching element, the periodic interval of applying the gate voltage, variable and in accordance with at least one of the ratio of the application period of the periodic interval for applying the gate voltage to the specification conditions of the power supply, the By controlling the resistance value of the conduction period of the second feeding path according to the current after conduction of the first feeding path of the contact relay, the power of the power supply branched to the second feeding path is averaged. However, the control step of averaging the predetermined voltage a voltage variation caused at the time of conduction of the first power supply path of the reed relay,
A rush prevention method characterized by performing. A contact relay that controls the continuity and opening of the first power supply path that connects the power supply and the load, and a second power supply that branches from the first power supply path and is connected to the load in parallel with the first power supply path. In an inrush prevention circuit having a switching element having a source into which the power of the power source branched into the path is input, a drain connected to the load in parallel with the first feeding path, and a control means.
The control means
The application period of the gate voltage before Symbol switching elements, periodic interval of applying the gate voltage, the ratio of the application period of the periodic interval for applying the gate voltage, the gate to conduct between the source and the drain of the switching element At least one of the voltage values of the voltage is varied according to the rating of the load, and the resistance value of the conduction period of the second feeding path is changed according to the current after the conduction of the first feeding path of the contact relay. A control step that, by controlling, averages the power of the power source branched to the second power supply path and averages the inrush current generated at the start of the load.
A rush prevention method characterized by performing.

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