Showing papers on "H bridge published in 1997"

Motor current sense circuit using H bridge circuits

Abstract: A circuit is used for sensing motor current. This circuit maximizes the power delivered to the motor whose current is being sensed. Further, this circuit results in maximum voltage drop across the motor. This circuit implements a mirrored H-bridge to mirror a current flowing through a conventional H -bridge having a sensing resistor in series with a VCM motor. The voltage drop across the sensing resistor serves as an indication of the current flowing

Operation of a fault tolerant PM drive for an aerospace fuel pump application

Abstract: In many applications the failure of a drive has a serious impact on the operation of a system. In some cases the failure results in lost production, whilst in others it may jeopardize human safety. In such applications it is advantageous to use a drive capable of continuing to operate in the presence of any single point failure. Such a drive is termed fault tolerant and the development of a fault tolerant drive is the aim of the research presented. Previous work by B.C. Mecrow et al. (see Seventh International Conference on Electric Machines and Drives, Durham, UK, IEE, p.443-7, 1995) has introduced the concept of a fault tolerant permanent magnet (PM) machine drive for safety critical applications. This drive was based on a novel design of PM machine with a high per unit reactance to limit fault currents. It is shown by A.G. Jack et al. (see IEEE Trans. Ind. Appls., vol.32, no.4, p.889-95, 1996) that the torque and power densities of this PM drive exceed those possible with an SRM drive. This previous work was undertaken on a small prototype machine without a power electronic converter. A new drive has now been built and extensively tested. It uses a similar topology to the prototype machine and is designed to an aircraft fuel pump specification, requiring 16 kW at 13000 rpm. This paper reports the key design attributes and provides detailed measured parameters. The machine is controlled by a power electronic converter using a separate "H bridge" to drive each phase. The controller, implemented via a DSP, uses the measured machine flux linkage to provide robust current control with high dynamic performance.

Multi-level converters: a real solution to high voltage drives?

Abstract: Multi-level converters are a small family of inverter circuit topologies whose final output voltage is made up by stepping through several intermediate voltage levels. Each of these topologies has a different mechanism for providing the voltage levels, and switching them to the output. The three main circuits are: the isolated H bridge circuit; the flying capacitor circuit; and the diode clamped circuit. This paper reviews these three topologies for use in high voltage high power variable speed AC motor drive. (5 pages)

Synchronous driving method for inductive load and synchronous controller for h-bridge circuit

Abstract: In flowing a switching current through an inductive load by way of an H-bridge circuit, a control circuit and a timing signal generating circuit are used to start a current supply operation in accordance with a driving period of a predetermined frequency, thereby increasing the current flowing through the inductive load. In reducing the current, a power source regeneration operation is performed during a power source regeneration period and a commutation operation is performed during a commutation period. The power source regeneration operation and the commutation operation are well balanced with each other, thereby making it possible to perform a high-frequency driving with a switching current having less ripple. Also, since the power source regeneration operation is performed in a long time in the case where the switching current level is reduced, it becomes possible to quickly reduce the current level down to a desired level.

Driving circuit having differential and H-bridge circuits for low voltage power source

Abstract: A driving circuit has first and second output terminals for connection with a load, for supplying the load with a constant voltage changing in polarity at predetermined timing, through the output terminals. A bridge circuit has first and second output nodes connected, respectively, to the first and second output terminals. A selector circuit selectively drives a plurality of current changeover switching elements of the bridge circuit. First and second differential amplifier circuits have first input terminals supplied with a predetermined reference voltage and second input terminals connected, respectively, to the first and second output nodes, and a common output terminal. A switching circuit selectively connects the first and second differential amplifier circuits to a power source in response to selective driving of the current changeover switching elements by the selector circuit. A bypass circuit is connected to the common output terminal of the first and second differential amplifier circuits to have conductivity thereof controlled by an output from the common output terminal, for bypassing part of current from the constant current source such that output voltage from the bridge circuit becomes equal to the predetermined reference voltage

Boost capacitor for an H-bridge integrated circuit motor controller having matching characteristics with that of the low-side switching devices of the bridge

Abstract: An H-bridge circuit having a boost capacitor coupled to the gate of the low-side driver. A driver, in the form of a switching transistor is connected between the load and ground, thus providing a low-side driver. A capacitor is coupled to the gate of the low-side driver to provide a boosted voltage for rapid turn on of the gate. The size of the capacitor selected to be similar to the size of the capacitance associated with the low-side driver transistor.

200 "C Operation of a 500 W DC-DC Converter Utilizing Power MOSFETs

Abstract: This paper presents results from the operation of the power stage of a 500-W dc-dc converter at an ambient temperature of 200 C. This converter is designed to provide an output voltage of 42-Vdc from a 28-Vdc input. It utilizes an H-bridge configuration composed of eight International Rectifier power MOSFET's (parallel connections of two MOSFET's) and four Motorola diodes to convert the dc input voltage to a high- frequency square wave which can then be stepped up with a transformer. The transformer output voltage is then rectified and filtered to produce the dc output voltage. A phase-shifted pulsewidth modulation (PWM) switching scheme is utilized to control the MOSFET's in the H bridge. This scheme allows zero-voltage turn-on of the MOSFET's to improve the efficiency. The efficiency of this converter when operated on the labo- ratory bench was measured to be 89%. The H bridge and transformer were then placed in an oven and operated over an ambient temperature range of 20 C-200 C. The efficiency varied from 86.1% to 85.4% over this temperature range. The long feedthroughs for oven operation caused the efficiency to decrease from 89% to 86.1%.

System and methods using a motor drive circuit to both drive a battery operated motor and to recharge the battery

Abstract: A battery-operated motor system includes a rechargeable battery, a motor and circuitry for recharging the battery. The recharging circuit processes externally applied energy to provide a source of recharging current. The recharging current is applied to a winding in the motor in the form of periodic current pulses. Following each pulse, energy thus stored in the motor winding is allowed to discharge into the battery, thereby recharging it. Use of the motor winding in this manner avoids the need to provide a separate inductance for recharging the battery and results in reduced weight, fewer components and greater manufacturing economy. The large inductance of the motor winding also enables recharging at a rate well suited to the particular motor/battery combination. By using existing components of a known H bridge motor drive to perform the various switching functions, further savings in these areas can be realized.

Three-phase induction motor driver

Abstract: PROBLEM TO BE SOLVED: To provide a three-phase induction motor driver in which the size and price can be reduced by employing an inverter. SOLUTION: A neutral terminal N is formed by employing a voltage doubler rectifying circuit comprising diodes 1, 2 and capacitors 3, 4 as a converting section. Three-phase power required for driving a three-phase induction motor 12 is taken out from the neutral terminal N and the AC output terminals A, B at an H bridge type inverting section comprising four switching elements 20-23. Since the number of switching elements is reduced by a factor of 3/2, the mounting area of power section is reduced by a factor of 3/2 and since heating of the switching elements is also reduced by a factor of 3/2, the heat radiation fin can be reduced in size resulting in a small and inexpensive three- phase induction motor driver. COPYRIGHT: (C)1999,JPO

Masking of switching noise in h bridge control

Abstract: PROBLEM TO BE SOLVED: To obtain a bridge-step control system which drives a reactive load so set as to function at a closed mode with the attenuation time of the upset condition generated when switches driven by the pair are turned from an off state to an on state being masked. SOLUTION: A bridge is driven at a closed loop mode by giving a pulse-width signal generated by a pulse width modulated generator 13 to an ON/RIC input pin of a bridge controller 11. That is, when the system is operated at a closed loop mode control phase using the pulse width modulated generator 13, a signal controller 14 is practically excluded. On the contrary, when the system is ordered to function at the closed loop mode based on the use of output signals generated by a sensitive comparator 12b and a zero-cross comparator 12a and the use of a signal generated by the pulse width modulated generator 13 by a basic aspect, the signal controller 14 conducts a controlling work.

Positive/negative pulse switching power unit

Abstract: PROBLEM TO BE SOLVED: To provide a positive/negative pulse switching power unit, which can make efficient stable pulse width control without being affected by the condition of a load even when the width of its output pulse is continuously changed from a narrow pulse width to a wide pulse width with a simple circuit configuration and a power source (single-sided power source) for its semiconductor switching elements. SOLUTION: Four semiconductor switching elements SW1, SW2, SW3, and SW4 are successively and repeatedly made to make switching operations in a fixed combined turning-on/off mode, by connecting the switching elements SW1, SW2, SW3 and SW4 in an H bridge and, at the same time, impressing a DC voltage upon an H-bridge switching circuit 1 in which the switching elements SW1, SW2, SW3, and SW4 are respectively connected in parallel with diodes D1, D2, D3, and D4, and supplying gate pulses to the gates of the switching elements SW1, SW2, SW3, and SW4 from a gate control circuit 4.

Print hammer bank and motor drive device

Abstract: A dot matrix printer and motor have hammers (24) forming in part a hammerbank (22) and a counterbalance (130) with a link to the position of the motor. The motor includes coils positively driven and then negatively driven after current in the coils has at least partially decayed. The current in the coils is allowed to decay further after negatively driving the coil. The motor coils are connected to an H bridge having transistors which can be formed in a full H bridge or half bridge. A controller switches the transistors to cause negative and positive flow through the H bridge for positive current flow from a reference level to an uper reference level, and a decay of current within the coils to an intermediate reference. The coils are then driven with a negative current from the intermediate reference level to a second intermediate reference level after which the current within the coil decays to a lower or initial reference level.

A robust lateral power MOSFET buffered H-bridge motor driver power IC

Abstract: A TTL compatible monolithic buffered H-bridge motor driver power IC implemented using low voltage power CMOS and capable of operating from 3.8 to 13.2 V is demonstrated experimentally for the first time. The buffered H-bridge is designed using an isolated lateral LDD-MOSFET structure in 2 /spl mu/m BCD technology. The transient failure mechanisms of the isolated lateral MOSFET in the H-bridge topology is contrasted to the non-isolated structure through experiments and device simulations. Experiments with inductive loads indicated that the operating voltage of the non-isolated MOSFET is limited to 9 V by the snap-back of the lateral parasitic NPN. It is shown in this paper, that the transient failure mode can be eliminated and the absolute maximum voltage increased to 15 V by using an isolated lateral MOSFET structure.