Controlled switching of non-regenerative power semiconductors
AssigneeGeneral Electric Company
InventorMilton D. Bloomer
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Abstract
Methods and circuitry for the controlled switching of non-regenerative power semiconductors to provide for a less rapid rate-of-change of load current while the power semiconductor is in its active region, thereby reducing electromagnetic interference. Methods and circuitry for the controlled turn-on with fast turn-off, controlled turn-off with fast turn-on or controlled turn-on and controlled turn-off of voltage-controlled and current-controlled semiconductors, with either load voltage (dV/dt) or load current (dI/dt) feedback are described.
Claims24
A method for the controlled switching, between a fully-turned-off condition and a fully-turned-on condition, of a non-regenerative power semiconductor device having a controlled current flow, with a conduction threshold and a saturation threshold, therethrough responsive to a control electrode signal, comprising the steps of:
- (a) providing a drive signal having first and second characteristics each respectively for directing the device to an associated one of the fully-turned-on and fully-turned-off conditions of the current flow therethrough;
- (b) selecting at least one direction of change between the first and second conditions of said drive signal as an associated controlled direction of change of the control electrode signal;
- (c) changing the control electrode signal at a first rate M responsive to a change of the drive signal in each selected controlled direction and until a first encountered one of the thresholds is reached;
- (d) then reducing the rate of change of the control electrode signal, in the controlled direction, to a second rate M' less than the first rate M, until the remaining one of the thresholds is reached;
- and
- (e) then increasing the rate of change of the control electrode signal in the controlled direction at another rate greater than the second rate M'.
Apparatus for controlling switching between a fully-turned-on condition and a fully-turned-off condition of a non-regenerative power semiconductor device having a controllable current flow, with a conduction threshold and a saturation threshold, therethrough responsive to a control electrode signal, comprising:
- means for receiving a drive signal having first and second characteristics each respectively for directing the device to an associated one of said fully-turned-on and fully-turned-off conditions of the current flow therethrough;
- first means for providing said control electrode signal responsive to the magnitude of a signal current;
- means, receiving said drive signal at said receiving means and responsive to at least one of the drive signal first and second characteristics, for providing the signal current to said first means to change the control electrode signal magnitude at a first rate M and in a direction selected responsive to an associated change in direction of said drive signal;
- and
- means for providing a feedback signal from said device to said current-providing means to change the signal current therefrom to said first means and reduce the rate of change of the control electrode signal to a second rate M', less than the first rate M, when the value of the controlled current flow through said device is between said conduction and saturation thresholds.
Dependencies are inferred from the claim text.